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Biomedical subjects

F Boué

Publications and source records attributed to F Boué.

At least 19 recordsLinked to original sources
PubMed2006

Dynamics of Puumala virus infection in bank voles in Ardennes department (France).

The hantaviruses (genus Hantavirus, family Bunyaviridae) include human pathogens and occur worldwide. In Western and Central Europe, the predominant serotype is Puumala (PUU) virus, which causes epidemic nephropathy. Voles are considered to be the main reservoir and the vector of PUU virus. A total of 719 rodents (mainly Clethrionomys glareolus, Apodemus sp.) trapped by capture-mark-recapture (CMR) in four sites in Ardennes department (France) between April 2004 and October 2005 were tested for the presence of PUU virus antibodies by enzyme-linked immunosorbent assay (ELISA). The predominant species, C. glareolus (86.5% [622 of 719]), also had the highest antibody prevalence (37.6% [291 of 773]). In C. glareolus, the antibody prevalence rate increased with age (weight) in site A, B and D, reaching more than 50% in the heaviest weight, and suggesting that horizontal infection may be important.

Animals↗
PubMed2004

Intra-vascular large B-cell lymphoma revealed by a nephrotic syndrome: a one year remission induced by a high frequency CHOP and rituximab.

Intra-vascular lymphoma is usually reported as a rare and fatal disorder. We describe here the first case of an intra-vascular lymphoma revealed by a nephrotic syndrome for which a durable remission has been obtained by 8 cycles of bi-mensual CHOP and Rituximab therapy. In this report, 18 fluorodesoxyglucose tomoscintigraphy is discussed as a tool for intra-vascular lymphoma extension and follow-up.

Aged↗
PubMed2004

Shear-induced concentration fluctuations and form factor changes in polymer solution in the good-solvent regime.

Small-Angle Scattering from sheared semidilute polymer solution is reported in the good-solvent regime, at variance with former light and neutron measurements in the theta regime. First, concentration fluctuations are observed: the scattering increases noticeably along the flow at low q, but at variance with former results for the theta-solvent regime, no demixing is observed at higher shear. Here, instead, the effects follow a time-temperature superposition and saturate above a Weissenberg number around 5, like the stress which is known to present a plateau for these systems. Using the Zero Average Contrast technique, we have also measured the form factor, which displays the same saturation effect reaching a deformation ratio of the order of 2. These results agree with the Convective Constraint Release models (CCR) elaborated in order to predict the stress effects in the non-Newtonian regime (Marrucci-Ianniruberto) and their extension predicting also the scattering (Likhtman-Milner-McLeish).

Biophysics↗
PubMed2003

Expression of the nucleoprotein of the Puumala virus from the recombinant Semliki Forest virus replicon: characterization and use as a potential diagnostic tool.

Puumala virus (Bunyaviridae family, Hantavirus genus) causes a mild form of hemorrhagic fever with renal syndrome (HFRS) called nephropathia epidemica in northern and central Europe. Serological tests are used for diagnosis, but antigen production is difficult because the virus grows poorly in tissue culture. We expressed the N protein (nucleoprotein) of Puumala virus via the Semliki Forest virus (SFV) replicon in mammalian cells and compared its antigenic properties with those of the native antigen derived from Puumala virus-infected cells. Detection of immunoglobulin G or immunoglobulin M by enzyme-linked immunosorbent assay (ELISA), micro -capture ELISA, and indirect immunofluorescence assay was (at least) as effective with the recombinant antigen as with the native antigen when HFRS patient sera or organ washes from wild rodents were tested. No nonspecific reaction was observed. Thus, the SFV-expressed N protein of Puumala virus appears as a valid antigen, specific and sensitive for serological investigations.

Animals↗
PubMed2003

Persistence length for a model semirigid polyelectrolyte as seen by small angle neutron scattering: a relevant variation of the lower bound with ionic strength.

In a SANS experiment, we have directly determined for the first time the conformation of hyaluronan, a model semirigid polyelectrolyte. At high ionic strength, this is completely possible, where the scattered intensity crosses over (when decreasing q) from a q(-1) rod variation to a q(-2) and, where fitting to the "wormlike" chain model gives the backbone, intrinsic, persistence length: L0 = 86.5 A. At low ionic strength, we can safely check that the measured persistence length appears increased by at least the amount predicted by Odijk for the electrostatic contribution, L(e) (approximately kappa(-2), square of the Debye screening length). However, the intensity at the lowest q is not only due to the single chain, since it crosses over from a q(-1) to a q(-4) variation, characteristic of polymer associations.

Journal Article↗
PubMed2002

Anisotropy of the structure factor of magnetic fluids under a field probed by small-angle neutron scattering.

Small-angle neutron scattering is used to measure the two-dimensional diffraction pattern of a monophasic magnetic colloid, under an applied magnetic field. This dipolar system presents in zero field a fluidlike structure. It is well characterized by an interaction parameter K(0)(T) proportional to the second virial coefficient, which is here positive, expressing a repulsion of characteristic length kappa-10. Under the field a strong anisotropy is observed at the lowest q vectors. The length kappa-10 remains isotropic, but the interaction parameter K(T) becomes anisotropic due to the long-range dipolar interaction. However, the system remains stable, the interaction being repulsive in all directions. Thus we do not observe any chaining of the nanoparticles under magnetic field. On the contrary, the revealed structure of our anisotropic colloid is a lowering of the concentration fluctuations along the field while the fluidlike structure, observed without field, is roughly preserved perpendicularly to the field. It expresses a strong anisotropy of the Brownian motion of the nanoparticles in the solution under applied field.

Journal Article↗
PubMed2001

Changes in AIDS-related lymphoma since the era of highly active antiretroviral therapy.

HIV infection is associated with a high incidence of AIDS-related lymphomas (ARLs). Since the use of highly active antiretroviral therapy (HAART), the incidence of AIDS-defining illnesses has decreased, leading to a significant improvement in survival of HIV-infected patients. The consequences of HAART use on ARL are under debate. This study compared the incidence and the characteristics of ARL before and after the use of HAART in a large population of HIV-infected patients in the French Hospital Database on HIV (FHDH) and particularly in 3 centers including 145 patients with proven lymphoma. Within the FHDH, the incidence of systemic ARL has decreased between 1993-1994 and 1997-1998, from 86.0 per 10 000 to 42.9 per 10 000 person-years (P < 10(-30)). The incidence of primary brain lymphoma has also fallen dramatically between the periods, from 27.8 per 10 000 to 9.7 per 10 000 person-years (P < 10(-11)). The analysis of 145 cases of ARL in 3 hospitals showed that known HIV history was longer in the second period than in the first period among patients with systemic ARL (98 versus 75 months; P <.01). Patients had a higher number of CD4 cells at diagnosis during the second period (191 versus 63/microL, P = 10(-3)). Survival of patients with systemic ARL also increased between the periods (from 6 to 20 months; P =.004). Therefore, the profile of ARL has changed since the era of HAART, with a lower incidence of systemic and brain ARL. The prognosis of systemic ARL has improved.

Antiretroviral Therapy, Highly Active↗
PubMed2001

Rituximab (anti-CD20 monoclonal antibody) as single first-line therapy for patients with follicular lymphoma with a low tumor burden: clinical and molecular evaluation.

The clinical activity of rituximab, a chimeric monoclonal antibody which binds to the CD20 antigen, was evaluated as a single first-line therapy for patients with follicular non-Hodgkin lymphoma (NHL). Fifty patients with follicular CD20(+) NHL and a low tumor burden were analyzed for clinical and molecular responses. They received 4 weekly infusions of rituximab at a dose of 375 mg/m(2). The response rate a month after treatment (day 50) was 36 of 49 (73%), with 10 patients in complete remission, 3 patients in complete remission/unconfirmed, and 23 patients in partial remission. Ten patients had stable disease, and the disease progressed in 3 patients. One of 13 (8%) patients in complete remission, 9 of 23 (39%) patients in partial remission, and 5 of 10 (50%) patients with stable disease exhibited disease progression during the first year. Within the study population, 32 patients were initially informative for polymerase chain reaction (PCR) data on bcl-2-J(H) rearrangement. On day 50, 17 of 30 patients (57%) were negative for bcl-2-J(H) rearrangement in peripheral blood, and 9 of 29 (31%) were negative in bone marrow; a significant association was observed between molecular and clinical responses (P <.0001). At month 12, 16 of 26 patients (62%) were PCR negative in peripheral blood. These results indicate that early molecular responses can be sustained for up to 12 months and that this response is highly correlated with progression-free survival. Rituximab has a high clinical activity and a low toxicity and induces a high complete molecular response rate in patients with follicular lymphoma and a low tumor burden.

Adolescent↗
PubMed2000

[Factors associated with medical management of HIV infected persons in two French districts, 1993-1995].

BACKGROUND: The regularity of medical followup of HIVinfected patients greatly influences the effectiveness of antiretroviral treatments and of prophylaxis of opportunistic infections. METHODS: To identify potential barriers to a regular followup, a retrospective study was conducted among the adult AIDS patients diagnosed between July 1993 and May 1995 in two French districts (Gironde and HautsdeSeine). Medical followup was described based on the frequency of CD4 counts in the medical file and on a confidential interview among patients whose HIV infection had been diagnosed at least 6 months before AIDS. Irregular followup (less than one CD4 count per year when CD4> 500/ mm(3), and per 6months when CD4< 500/ mm(3)) within the two years preceding AIDS diagnosis was analysed according to socioeconomic status and to social and behavioral factors. RESULTS: Among 290 patients, followup was irregular in 51% of the patients (injecting drug users: 66%, homo/bisexual men: 41%, patients infected through heterosexual contact: 49%, p<0.01). Factors independently associated with irregular followup were low income level (adjusted odds ratio (aOR)= 2.4; 95% confidence interval (CI), 1.44.1); absence of regular practitioner at HIV diagnosis (aOR= 1.9; 95% CI 1.13.3); imprisonment between HIV diagnosis and AIDS (aOR= 3.8; 95% CI 1.310. 9), and being non homo/bisexual male (aOR= 2.4; 95% CI 1.15.1) versus homo/bisexual male (aOR= 1.3; 95% CI 0.72.7) and female (reference). CONCLUSIONS: Results of this study show that several socioeconomic, psychological and cultural barriers to a regular preAIDS medical followup still exist. Impact of new antiretroviral therapy may only be optimal if these barriers are overcome.

AIDS-Related Opportunistic Infections↗
PubMed1999

Survival improvement of AIDS-related progressive multifocal leukoencephalopathy in the era of protease inhibitors. Clinical Epidemiology Group. French Hospital Database on HIV.

OBJECTIVE: To estimate the change in survival of patients with AIDS-related progressive multifocal leukoencephalopathy (PML), in relation to the introduction of protease inhibitors (PI). DESIGN: The French Hospital Database on HIV (FHDH) is a prospective cohort of 70 224 HIV-infected subjects. This study included the patients diagnosed with PML between 1 July 1995 and 30 June 1997. PML diagnosis was both presumptive and confirmed. We compared the survival probability according to the diagnosis period (period 1 or 2, before or after introduction of PI in France on 1 April 1996). Cox's model was used to calculate the relative hazards of death according to the antiretroviral regimen. RESULTS: The study included 246 patients, 109 diagnosed during period 1 and 137 during period 2. In all, 131 patients received an antiretroviral combination that included PI. By 31 December 1997, a total of 131 deaths had been reported. The probability of survival at 6 months for patients from period 2 was nearly twice as high as for patients from period 1 (60.5 versus 34.5%). In comparison with patients receiving no treatment, the risk of death in patients on combination therapy not including PI was reduced by 38% [relative hazard (RH) 0.62, 95% confidence interval (CI) (0.41; 0.95), P = 0.026] and in patients on combination therapy with PI, by 63% [RH 0.37, 95% CI (0.22; 0.64), P = 0.0004]. CONCLUSION: This study of a large cohort of patients diagnosed with PML (n = 246), provides evidence that a combination antiretroviral regimen, especially one including PI, confers marked survival benefits.

AIDS-Related Opportunistic Infections↗
PubMed1999

Disclosure of HIV seropositivity.

Deciding whether or not to disclose one's HIV-positive status to another person is an important decision: the way each person experiences and copes with the illness is reflected in this choice. We conducted a study of 174 patients (29.3% of women) to examine how the decision to disclose or conceal was made, as well as its subjective and social consequences. We discovered that only 3.5% of the individuals remained silent about their illness. Most spoke about it, regardless of how they had been infected or of the advice they had received to be discrete. The confession often did not bring them the relief they sought. Revealing one's HIV-positive status is not a sign of social responsibility, or of a special trust in someone, but rather a compulsive act to release suppressed tension. Individuals who do not confess need attention; their silence is a sign of their inability to adapt to their illness, as well as of their self-imposed exclusion from society.

Adaptation, Psychological↗
PubMed1999

Hamster sperm antigen P26h is a phosphatidylinositol-anchored protein.

We have previously identified a hamster sperm protein, P26h, proposed to be involved in the interaction between spermatozoa and the egg's zona pellucida. In this study we investigated the mechanism of P26h accumulation on hamster spermatozoa during epididymal maturation. Immunocytochemical studies showed an accumulation of P26h on the acrosomal cap of hamster spermatozoa during epididymal transit. To document the anchoring mechanism of P26h, cauda epididymal spermatozoa were exposed to different treatments. High-salt buffered solutions were unable to remove P26h from the surface of intact spermatozoa. P26h was released in a dose-dependent manner when live spermatozoa were treated with a solution of phospholipase C specific to phosphatidylinositol. In contrast, the P26h remained associated to the sperm surface following treatment with trypsin. To document the transfer mechanisms of P26h on the maturing spermatozoa, prostasomes were isolated from the epididymal fluid and subjected to immunodetection. Western blots and immunogold studies showed that P26h was associated to epididymal prostasomes. Phospholipase C treatment performed on epididymal prostasomes, indicated that P26h also is anchored to these vesicles via a phosphatidylinositol. These results suggest that epididymal sperm maturation involves a cell to cell transfer of a phosphaditylinositol-anchored protein and that prostasomes may be implicated in this process.

Alcohol Oxidoreductases↗
PubMed1999

Constrained evolution of human immunodeficiency virus type 1 protease during sequential therapy with two distinct protease inhibitors.

Human immunodeficiency virus type 1 (HIV-1) variants that have developed protease (PR) inhibitor resistance most often display cross-resistance to several molecules within this class of antiretroviral agents. The clinical benefit of the switch to a second PR inhibitor in the presence of such resistant viruses may be questionable. We have examined the evolution of HIV-1 PR genotypes and phenotypes in individuals having failed sequential treatment with two distinct PR inhibitors: saquinavir (SQV) followed by indinavir (IDV). In viruses where typical SQV resistance mutations were detected before the change to IDV, the corresponding mutations were maintained under IDV, while few additional mutations emerged. In viruses where no SQV resistance mutations were detected before the switch to IDV, typical SQV resistance profiles emerged following the introduction of IDV. We conclude that following suboptimal exposure to a first PR inhibitor, the introduction of a second molecule of this class can lead to rapid selection of cross-resistant virus variants that may not be detectable by current genotyping methods at the time of the inhibitor switch. Viruses committed to resistance to the first inhibitor appear to bear the "imprint" of this initial selection and can further adapt to the selective pressure exerted by the second inhibitor following a pathway that preserves most of the initially selected mutations.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Determinants of delayed diagnosis of HIV infection in France, 1993-1995.

OBJECTIVE: To describe the circumstances of the first HIV-positive test and to study the determinants of a delayed diagnosis of HIV infection. METHODS: In a retrospective study among adult AIDS patients diagnosed between July 1993 and May 1995 in two French districts, data on socioeconomic characteristics, circumstances of first HIV-positive test and attitudes and behaviours regarding medical care were collected in a confidential interview and analysed for potential association with a late test, defined as a first HIV-positive test within 6 months of AIDS diagnosis. RESULTS: Of the 359 AIDS patients studied, 69 (19.2%) had a late test. Late testers were more likely than other patients to have had an HIV-positive test because of clinical symptoms (89.7 versus 38.9%, P < 0.001) and not to perceive themselves as being at risk of infection with HIV (53.6 versus 39.3%, P < 0.05). The proportion of late testers was 34.6% among heterosexually infected patients, 12.7% among homo-/ bisexual men and 9.6% among injecting drug users. Factors independently associated with a late test were male gender [adjusted odds ratio (aOR), 5.6; 95% confidence interval (CI), 1.7-18.9] and absence of earned income (aOR, 5.2; 95% CI, 1.4-19) among heterosexually infected patients; high education (aOR, 3.1; 95% CI, 1.0-9.6) and having consulted a person practising alternative medicine (aOR, 3.4; 95% CI, 1.2-10) in homo-/bisexual men. CONCLUSIONS: Despite incentives to be tested for HIV, many individuals in France are still tested too late, even if they are in known high-risk groups. Efforts to test HIV-infected people as early as possible should be made by increasing the perception of HIV risk and decreasing the level of missed opportunities for testing. Current case management approaches make this recommendation critically important from both public health and an individual perspective.

Adult↗
PubMed1998

Catastrophic antiphospholipid syndrome. Clinical and laboratory features of 50 patients.

We analyzed the clinical and laboratory characteristics of 50 patients with catastrophic antiphospholipid syndrome (APS) (5 from our clinics and 45 from a MEDLINE computer-assisted review of the literature from 1992 through 1996). Thirty-three (66%) patients were female and 17 (34%) were male. Twenty-eight (56%) patients had primary APS, 15 (30%) had defined systemic lupus erythematosus (SLE), 6 (12%) had "lupus-like" syndrome, and 1 (2%) had rheumatoid arthritis. Mean age of patients in this series was 38 +/- 14 years (range, 11-74 yr). Three (6%) patients developed the clinical picture of catastrophic APS under the age of 15 years, and 11 (22%) were 50 years old or more. In 11 (22%) patients, precipitating factors contributed to the development of catastrophic APS (infections in 3, drugs in 3, minor surgical procedures in 3, anticoagulation withdrawal in 2, and hysterectomy in 1). The presentation of the acute multi-organ failure was usually complex, involving multiple organs simultaneously or in a very short period of time. The majority of patients manifested microangiopathy--that is, occlusive vascular disease affecting predominantly small vessels of organs, particularly kidney, lungs, brain, heart, and liver--with a minority of patients experiencing only large vessel occlusions. Thrombocytopenia was reported in 34 (68%) patients, hemolytic anemia in 13 (26%), disseminated intravascular coagulation in 14 (28%), and schistocytes in 7 (14%). The following antibodies were detected: lupus anticoagulant (94%), anticardiolipin antibodies (94%), anti-dsDNA (87% of patients with SLE), antinuclear antibodies (58%), anti-Ro/SS-A (8%), anti-RNP (8%), and anti-La/SS-B (2%). Anticoagulation was used in 70% of the patients, steroids in 70%, plasmapheresis in 40%, cyclophosphamide in 34%, intravenous gammaglobulins in 16%, and splenectomy in 4%. Most patients, however, received a combination of nonsurgical therapies. Death occurred in 25 of the 50 (50%) patients. In most, cardiac problems seemed to be the major cause of death. In several of these, respiratory failure was also present, usually due to acute respiratory distress syndrome and diffuse alveolar hemorrhage. Among the 20 patients who received the combination of anticoagulation, steroids, and plasmapheresis or intravenous gammaglobulins, recovery occurred in 14 (70%) patients. The use of ancrod and defibrotide appeared to be effective in the 2 respective patients in whom they were used.

Adolescent↗
PubMed1998

[Risk reduction and intravenous drug use abstinence in patients with HIV infection. The SEROCO group].

BACKGROUND: Little is known about the complex stepwise process of giving up intravenous (i.v.) drugs. However, HIV risk reduction programs directed towards i.v. drug users have been accused by some opponents to encourage users to continue. In order to better assess the relationships between risk reduction and abstinence, we studied factors associated with abstinence in HIV-infected patients using i.v. drugs at enrollment in the SEROCO cohort (1988-1994). METHODS: 63 HIV-infected patients injecting i.v. drugs at enrollment were followed-up every 6 months with a clinical examination and a questionnaire concerning sexual and drugs practices since last consultation. Abstinence was defined as non injecting for at least 6 months. The 30 patients who became abstinent during a follow-up period of 3 years were compared to the 33 remaining. RESULTS: Abstinence during follow-up was not related to age at inclusion, duration of i.v. drug use, gender or marital status. However, patients who became abstinent were more likely to have a professional activity at inclusion than the remaining (70% vs 42%, p = 0.03). Before knowledge of HIV infection, frequency of injections, needle sharing and use of condoms did not differ between the 2 groups. During follow-up, behavioural changes occurred in the two groups, but were more marked in those who lately became abstinent. These latter were more likely to always inject with new needles/syringes (57% vs 18%, p = 0.003), and to use condoms with HIV-negative partners or of unknown status (73% vs 39%, p = 0.06). Professional activity and systematic use of new needles/syringes remained independently associated with abstinence in multivariate analysis. CONCLUSION: In this cohort, abstinence appeared as a stepwise process in which risk reduction preceded abstinence. This confirms that risk reduction programs do not work against those messages aimed at stopping i.v. drug use. Since this analysis selected particular subjects, enrolled in a cohort of HIV-infected patients, results should be confirmed in other samples of i.v. drugs users.

Adult↗
PubMed1997

Immunosenescence in HIV pathogenesis.

Telomeres are complex protein-DNA structures located at the ends of eukaryotic chromosomes. In a normal cell, telomere DNA shortens with cell divisions. Such a telomere loss may act as a mitotic clock to eventually signal cell cycling exit and cellular senescence. In a transversal study, we found a marked decrease in telomere length of peripheral blood mononuclear cells in HIV-infected patients with advanced immunodeficiency. This telomere reduction concerns T4, T8, and B lymphocytes, providing evidence of high turnover of these cells in the course of HIV infection. These data suggest that replicative senescence could be involved in the final immunosuppression and may have important therapeutical implications.

Adult↗