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Biomedical subjects

F Simon

Publications and source records attributed to F Simon.

At least 109 records · Page 6Linked to original sources
PubMed1996

Psychological factors in the diagnosis and pathogenesis of stiff-man syndrome.

Retrospective psychological evaluation of nine patients with stiff-man syndrome (SMS), seven of whom evidenced autoimmune disease, revealed a characteristic set of psychological symptoms or features: Major stressful life events preceded the development of permanent symptoms by 6 months or less (seven patients); transient motor symptoms occurred in emotionally distressing situations months or even years before the onset of a permanent motor deficit (five patients); after onset, similar situations specifically precipitated or augmented stiffness and spasms (five patients). We also found task-specific fear resembling agoraphobia (six patients) and loss or invalidation of one or both parents, or loss of home, in childhood (seven patients). Eight patients were initially misdiagnosed as having psychogenic movement disorder. We conclude that the common misdiagnosis of SMS as a psychogenic movement disorder is due to the compelling association of a set of salient psychological features, bizarre and fluctuating motor symptoms, and lack of approved neurologic signs.

Adult↗
PubMed1996

Fluorometric detection of HIV-1 genome through use of an internal control, inosine-substituted primers, and microtiter plate format.

We describe a PCR-based fluorometric assay for the detection of the HIV-1 genome. This technique consists of a reverse hybridization with oligonucleotide probes covalently coated onto a microtiter plate as a solid support. Several improvements to the PCR amplification and detection steps gave greater sensitivity and specificity for HIV-1 screening and resulted in a convenient and rapid technique. False-positive results were avoided by using uracyl DNA glycosylase. False-negative results from the presence of PCR inhibitors were detected by coamplifying an internal control with the viral sequence. False-negative results from viral genome variability were limited by using two pairs of primers and by incorporating inosine at the primer positions corresponding to viral polymorphic nucleotides. Furthermore, the hybridization buffer and enzymatic reaction were optimized to increase the assay's sensitivity. The sensitivity and specificity of the fluorometric detection were similar to those of radioisotopic oligonucleotide solution hybridization; however, hands-on time was reduced, and the use of radioactivity was eliminated. We have used this technique routinely on 115 samples and obtained 100% specificity and high sensitivity (only one false-negative result) according to viral culture and (or) serological status of the patients.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Virulence of human immunodeficiency virus].

Virulence is relative capacity of a virus, compared to other closely related viruses, to produce disease in a host. Viral strains considered as virulent have been described in HIV-1 infected patients. They are characterized in vitro by enhanced cellular host range, rapid kinetic of replication and increased capacity of syncytium induction. Some genetic modification of the V3 loop in the envelope gene have been associated with the emergence of these strains. But at AIDS diagnosis, and even at the terminal stage of AIDS, only about half of the patients harbour syncytium inducing variants. There are much evidence for continuous viral replication throughout all stages of HIV-1 infection. There is no viral latency state in the natural HIV infection. This increasing viral burden might have a pivotal role in the pathogenesis of HIV disease. HIV-2 is less pathogenic than HIV-1. The nature of the viral determinants responsible for this reduced virulence remains unknown. In the simian immunodeficiency virus model, virulent and avirulent strains have been described and the nef gene seems to have a critical role in pathogenicity.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Reactivity of five anti-HIV-1 subtype O specimens with six different anti-HIV screening ELISAs and three immunoblots.

Five anti-subtype O specimens were tested by anti-HIV-1/2 screening and confirmatory assays. They can be divided into three specimens, reactive with all ELISAs, independent of the nature of the antigen (recombinant proteins or peptides) and test configuration (indirect ELISA or double antigen/sandwich ELISA). One specimen was not detected by one peptide based ELISA. One specimen was only recognized by two ELISAs and should be considered as a marker sample for the weakness of currently used ELISAs with anti-subtype O. Three different immunoblot assays available commercially detected two of the specimens with a major binding of gp160 and other viral bands, especially the integrase and reverse transcriptase. Another two specimens lacked reactivity with glycoproteins almost completely, but showed some staining with the enzymes of HIV, and would most probably be interpreted as indeterminate. The fifth specimen, which was also missed by most of the ELISAs, had very faint staining of the gp160 and a very weak staining of p24, and would most probably be interpreted as negative. Adaption of currently available tests to anti-subtype O is needed for the future reliability of anti-HIV diagnostic reagents.

AIDS Serodiagnosis↗
PubMed1995

Immunocytochemical study of lampbrush chromosomes of the urodele Pleurodeles waltl: axial granules are recognized by the mitosis-specific monoclonal antibody MPM-2.

The lampbrush chromosomes of the urodele Pleurodeles waltl have been studied using the mitosis-specific monoclonal antibody MPM-2. Immunofluorescence studies revealed that MPM-2 stains structures associated with axial granules, numerous other chromomeres, telomeres and certain chiasmata. These structures showed a negative reaction with the anti-DNA monoclonal antibody AC-30-10. In course of meiotic condensation of the chromosomes, in growing and maturating oocytes, the number of such structures associated with the chromosome axis was found to diminish progressively. These granular structures have been found to be formed by fine fibrils about 5 nm in diameter. Immunogold labeling confirmed the results of immunofluorescence studies. MPM-2 was also found to stain two other types of structures observed in association with the lampbrush chromosome axis in P waltl, viz the sphere organelle (only in later stages of oogenesis) and the structure known as 'M' which is singular to this material.

Animals↗
PubMed1995

Reduced capacity of antibodies from patients infected with human immunodeficiency virus type 1 (HIV-1) group O to neutralize primary isolates of HIV-1 group M viruses.

Neutralizing antibody patterns in sera of persons infected with human immunodeficiency virus type 1 (HIV-1) groups M and O to their homologous and heterologous primary isolates were determined in a peripheral blood mononuclear cell-based neutralization assay and correlated with their ability to bind to V3 loop synthetic peptides. Most HIV-1 group M sera (9/16) neutralized HIV-1 group O viruses, whereas fewer group O sera (3/13) only weakly neutralized HIV-1 group M viruses. Group M sera neutralizing HIV-1 group O viruses neutralized other HIV-1 group M viruses with titers of 1:10-1:1280. V3 loop binding capacity of sera did not reflect their neutralizing capacity of the homologous isolate. Despite the reduced neutralizing capacity of group O-infected patients' sera to group M viruses, some group M-infected patients' sera neutralized both HIV-1 group M and O isolates, suggesting that they share some conserved neutralizing epitopes.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Variability of human immunodeficiency virus type 1 group O strains isolated from Cameroonian patients living in France.

Human immunodeficiency virus type 1 (HIV-1) nucleotide sequences encoding p24Gag and the Env C2V3 region were obtained from seven patients who were selected on the basis of having paradoxical seronegativity on a subset of HIV enzyme-linked immunosorbent assay detection kits and having atypical Western blot (immunoblot) reactivity. Sequence analyses showed that all of these strains were more closely related to the recently described Cameroonian HIV isolates of group O (HIV-1 outlier) than to group M (HIV-1 major). All seven patients had Cameroonian origins but were living in France at the time the blood samples were taken. Characterization of a large number of group M strains has to date revealed eight distinct genetic subtypes (A to H). Genetic distances between sequences from available group O isolates were generally comparable to those observed in M intersubtype sequence comparisons, showing that the group O viruses are genetically very diverse. Analysis of sequences from these seven new viral strains, combined with the three previously characterized group O strains, revealed few discernable phylogenetic clustering patterns among the 10 patients' viral sequences. The level of diversity among group O sequences suggests that they may have a comparable (or greater) age than the M group sequences, although for unknown reasons, the latter group dispersed first and is the dominant lineage in the pandemic.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Limits of PINI (prognostic nutritional anf inflammatory index) in the evaluation of nutritional status in children].

The prognosis inflammatory and nutritional index (PINI) is a score based on albumin, glycoprotein acid and C-reactive protein levels. PINI was developed to evaluate nutritional and inflammatory status of patients presenting inflammatory syndromes with or without denutrition. In the present study conducted over a period of 6 days in the Pediatric Department of Bambri Hospital in the Central African Republic, we evaluated the usefulness of PINI for follow-up of 25 undernourished Central African children presenting marasmus (n = 15) or kwashiorkor (n = 10) associated with a laboratory documented inflammatory process. All children received nutritional support. We assessed the influence of inflammatory and nutritional factors on PINI values. Data measured in blood samples taken from 16 patients who also presented documented inflammatory manifestations but were not undernourished. A parallel decrease in C-reactive protein and PINI was observed from D0 to D6 and an increase in albumin and prealbumin from D3. There was a positive correlation between C reactive protein values and PINI on D0, D3 and D6. There was no significance difference between PINI and C reactive protein levels in the two study groups. In contrast, a significant difference was observed between albumin and prealbumin. These findings indicate that PINI is of little value for evaluation of inflammatory processes associated with malnutrition. The two main drawbacks of PINI are first that it is more sensitive to the inflammatory than nutritional factors and second that the physical and pharmakinetic parameters used for its calculation are too different.

C-Reactive Protein↗
PubMed1994

HIV-1/HIV-2 seronegativity in HIV-1 subtype O infected patients.

Nine patients with atypical HIV-1 western blot profiles were diagnosed as having HIV-1 subtype O infection. All the patients were living in France; eight originated from Cameroon and one from France. Lymphocyte DNA amplification by the polymerase chain reaction was only positive when HIV-1 subtype O specific primers were used. Preliminary sequence analysis of amplified products and serological reactivity against a specific subtype O synthetic env peptide confirmed HIV-1 subtype O infection. HIV-1/HIV-2 enzyme-linked immunosorbent assays, especially those based on env peptides or on the sandwich format, can be negative in HIV-1 subtype O infection.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Localization of antigens PwA33 and La on lampbrush chromosomes and on nucleoplasmic structures in the oocyte of the urodele Pleurodeles waltl: light and electron microscopic immunocytochemical studies.

Monoclonal antibodies A33/22 and La11G7 have been used to study the distribution of the corresponding antigens, PwA33 and La, on the lampbrush chromosome loops and nucleoplasmic structures of P. waltl oocytes, using immunofluorescence, confocal laser scanning microscopy and immunogold labeling. The results obtained with these antibodies have been compared with those obtained with the Sm-antigen-specific monoclonal antibody Y12. All these monoclonal antibodies (mAbs) labeled the matrices of the majority of normal loops along their whole length. Nucleoplasmic RNP granules showed a strong staining with the mAbs La11G7 and Y12 throughout their mass, but with the mAb A33/22, they showed only a weak peripheral labeling in the form of patches on their surface. This patchy labeling was confirmed by confocal laser scanning microscopy. Electron microscopy revealed that this patchy labeling might be due to a hitherto undescribed type of submicroscopic granular structure, around 100 nm in either dimension, formed by 10-nm particles. Such granules were observed either attached to the RNP granules or free in the nucleoplasm, but rarely in relation with the normal loop matrices. These 100-nm granules may have a role in the movement of proteins and snRNPs inside the oocyte nuclei for storage, recycling, and/or degradation. Our results also suggest that all the microscopically visible free RNP granules of the nucleoplasm of P. waltl oocytes correspond to B snurposomes. The granules forming the B (globular) loops showed a labeling pattern similar to that of B snurposomes; their possible relationship is discussed.

Animals↗
PubMed1994

An observational study of 11 French liver transplant recipients infected with human immunodeficiency virus type 1.

We report the clinical and biological course of infection with human immunodeficiency virus (HIV) type 1 in 11 liver transplant recipients who acquired this infection between 1985 and 1987. Eight patients were infected by blood or blood products from graft-related transfusions and one by the graft itself; the remaining two patients were infected after transplantation and had independent risk factors. All patients received a triple-drug immunosuppressive regimen including cyclosporine. The mean duration of follow-up after liver transplantation was 52 months (standard error, +/- 32 months). Chronic graft rejection was documented in four cases. The cumulative incidences of HIV-related complications and HIV-related deaths were 82% and 27%, respectively. Three patients died rapidly of HIV disease. The survival rate 7 years after transplantation was 36% among the 11 HIV-infected patients, whereas it was approximately 70% among HIV-negative liver transplant recipients during the same period. The course of HIV infection in the four survivors did not appear to differ from that in other patients infected by blood transfusion.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Comparison of plasma cytokine levels in African patients with HIV-1 and HIV-2 infection.

OBJECTIVE: To determine plasma cytokine levels [tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta and IL-6] in African patients infected with HIV-2 relative to values in HIV-1-infected patients, and their relation to immunologic and clinical status. DESIGN: Questions about the observed differences in the pathogenesis of HIV-2 and HIV-1 remain unanswered. Cytokines, especially TNF-alpha, are involved in the regulation of HIV-1 replication, and can be found in the plasma of HIV-1-infected individuals. Therefore, we evaluated TNF-alpha, IL-1 beta and IL-6 levels in the plasma of African patients with different stages of HIV-2 disease. This was a 3-year prospective follow-up study. METHODS: Cytokine plasma levels were assayed in 40 HIV-2- and 51 HIV-1-infected patients from Africa. Nineteen of the 40 HIV-2-infected-patients underwent serial assays every 4 months for 3 years. Data were analysed in relation to the number of CD4+ and CD8+ cells, viral load and clinical status. RESULTS: Plasma levels of TNF-alpha and IL-1 beta were significantly higher in all the HIV-1- and HIV-2-infected patients than in healthy controls; IL-6 levels were around the detection limit for all patients. TNF-alpha levels were lower in the HIV-2-infected than in the HIV-1-infected patients at all Centers for Disease Control and Prevention (CDC) disease stages, including the asymptomatic phase. The CD4+ cell count was always higher in the HIV-2-infected patients, regardless of CDC stage. The prospective follow-up showed that TNF-alpha levels remained stable during the course of HIV-2 disease, as did the CD4+ cell count and virus load. CONCLUSION: Lower and stable plasma TNF-alpha levels in African patients infected with HIV-2, associated with lower viral load and higher CD4+ cell count, suggests the existence of a more appropriate and efficient immune response to HIV-2 than to HIV-1.

AIDS Serodiagnosis↗