Comparative assessment of five alternative methods for CD4+ T-lymphocyte enumeration for implementation in developing countries.
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CD4 Lymphocyte Count↗
Biomedical subjects
J M Didier
Publications and source records attributed to J M Didier.
In situ PCR to cells and to wax sections. An alternative to in situ hybridization for the detection of low copies of human papillomavirus and cytomegalovirus DNA.
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Cells↗
[Immediate allergy to anesthetics of the amide group].
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Anesthetics, Local↗
Serum secretory immunoglobulins in ankylosing spondylitis.
Humoral mucosal immunity may be implicated in pathophysiology of ankylosing spondylitis (AS). The aim of the study was to evaluate serum levels of IgA, IgM and secretory IgA (sIgA), secretory IgM (sIgM) as well as free secretory component (FSC) in patients with AS compared to controls and rheumatoid arthritis (RA) patients. Levels of sIgA, sIgM and FSC were measured with a specific ELISA in 37 AS patients, 45 controls and 27 RA. The results were as follows: Serum levels of IgA were higher in AS vs controls and in RA vs controls (p = 0.01). Levels of sIgA were higher in AS vs controls (p = 0.01), but higher in RA vs AS (p = 10(-4)). There was no difference of sIgM in AS vs controls, FSC levels were higher in AS vs controls, and higher in AS patients with elevated CRP. In view of elevated FSC, this increase of sIgA in AS may have been due to excessive production of mucosal IgA after bacterial stimulation according to the current hypothesis of the disease.
Adult↗
Effects of a selective sleep deprivation on subsequent anaerobic performance.
The aim of the study was to investigate the effects of a partial sleep deprivation on a subsequent supramaximal exercise evaluated from the 30 second Wingate test, and on the following recovery. To take into account the active muscle mass, the Wingate test was performed against a constant braking force related to the data of a force-velocity test conducted on a Monark cycle ergometer (Model 814 E with weights) one week before the experimental test. Eight highly trained athletes were enrolled for this study. The changes in ventilatory and metabolic responses were analyzed during and upon completion of physical 30 second exercise, taking place after two nights, in other words, after a reference night and after a night with reduced sleep. Partial sleep deprivation was obtained by delaying bedtime until 3 a.m. The 30 second Wingate test was performed between 9 a.m. and noon the following days, using a Monark ergometer (Model 814 F). The analyses of change scores disclosed that there were no main significant effects for measures of ventilation, lactates and pH(v) levels under the two experimental conditions. The peak power, the mean power output and the peak velocity recorded after partial sleep deprivation were not modified in comparison with the values obtained after the reference night. These findings suggest that acute sleep loss did not contribute to alterations in supramaximal exercise.
Adolescent↗
Function of the oxidative metabolism of phagocytes in elderly people: relationship to nutritional and inflammatory status.
The purpose of this study was to investigate the phagocyte production of oxygen-free radicals (OFR) in the whole blood of elderly patients (EP), by measuring chemiluminescence at the basal state and after stimulation, and to study the relationships between its impairment, if any, and blood indices of the nutritional and inflammatory status in elderly patients with (Inf) and without (N-Inf) inflammatory diseases. The results showed that OFR production by resting circulating phagocytes, assessed by chemiluminescence on whole blood, is markedly increased in EP, irrespective of any in vitro stimulation. The significant correlation we found between basal chemiluminescence and immunoglobulins levels, IgM, IgG and IgA in the whole EP sample, and IgG in the N-Inf group, suggests that it could be linked to the cytokine imbalance that favours Th2- and impairs Th1-type of cytokine production by T-cells in EP. The basal overproduction of OFR was observed both in Inf and N-Inf EP and unexpectedly was less marked in group Inf EP. This observation suggests a relative impairment in EP phagocytic adaptive responses to inflammatory conditions. This suggestion was confirmed by the absence of significant differences between the chemiluminescence index CLI calculated after phorbol myrisate acetate (PMA) stimulation in group Inf vs. N-Inf EP, and by the lower CLI observed in group Inf phagocytes stimulated by opsonized zymosan. The role of blood changes associated with inflammation and/or nutrition in this relative impairment is supported by the positive correlations that we observed between CLI and acute-phase proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
Acute-Phase Reaction↗
[Detection of cyclin A mRNA in intra-epithelial lesions of the anogenital tract induced by papillomavirus].
Human papillomaviruses (HPVs) have been recognized as likely viral agents responsible for anogenital precancer lesions and squamous cell cancers in both men and women. Nevertheless their role in carcinogenesis is not entirely clear. There are many other agents, both viral and non-viral, which might act synergistically or separately with HPV in a multistep tumorigenic process. Among non-viral factors, protooncogene and tumor suppressor gene alterations may be a major step towards the malignant transformation of an HPV-infected cell. The induction of unscheduled DNA synthesis and cell proliferation by human papillomaviruses would provide the basis for the potential of these viruses to contribute to the formation of tumors in vivo. Thus, we studied by in situ hybridization (ISH) the cyclin A gene expression in HPV-induced condylomatous and dysplastic lesions of the anogenital tract, and in inflammatory squamous intraepithelial tissues. We observed a high level of cyclin A gene expression in low grade squamous intraepithelial lesions infected by HPV type 6/11. Cyclin A induction was surprisingly more important in the upper third layers of differentiated cells together with large amounts of HPV DNA, than in proliferating basal and parabasal cells. An identical pattern was also shown in some low grade squamous intraepithelial lesions infected with potential oncogenic HPV. In contrast, there was evidence of low abundance cyclin A mRNA in most high grade squamous intraepithelial lesions induced by high risk HPV. In the inflammatory tissues, an ISH signal was sometimes detected in the basal cells. As for proliferating cell nuclear antigen (PCNA), these results observed in vivo reveal that viral oncoproteins are able to reactivate cellular DNA replication machinery to support papillomavirus DNA replication in normally differentiated, non-cycling cells. The induction of cyclin A gene expression appears to correlate with the proliferative rather than the transforming properties of these cells.
Anus Diseases↗
Detection of human papillomavirus by in situ polymerase chain reaction in paraffin-embedded cervical biopsies.
The efficiency of the in situ polymerase chain reaction (PCR) for the detection of human papillomavirus (HPV) DNA sequences in 20 cervical biopsies fixed with buffered formalin, paraffin-embedded and revealed negatively by conventional in situ hybridization (ISH) has been investigated. The biopsies were classified histologically into condylomata acuminata without dysplasia, cervical intraepithelial neoplasia and carcinoma in situ. Amplified HPV DNA was performed after an optimal proteolytic digestion using one pair of consensus oligonucleotide primers located in the L1 ORF of HPV 6 and ISH was carried out after the PCR assay with a cocktail of biotinylated HPV probes. Viral DNA was detected in 100% of high grade squamous intraepithelial lesions (SIL) and in 50 to 60% of low grade SIL. The high sensitivity of the in situ PCR applicable to paraffin-embedded archival biopsies facilitated the detection of cells poorly reactive by conventional ISH. In situ PCR appeared clearly an efficient tool to investigate HPV infection in tissue sections.
Base Sequence↗
Comparison of age-dependent antigen recognition in two communities with high and low Trichuris trichiura transmission.
A previous ELISA-based study using whole worm extract, compared age-antibody profiles in two communities with high and low levels of Trichuris trichiura transmission (Needham et al., 1992). This showed that specific IgG1 levels mirrored infection intensity at the population level, while IgA levels exhibited a weak trend to remain elevated in the adult age classes in the area of highest transmission. This was interpreted as preliminary evidence for IgA-mediated resistance in the population with greatest prior experience of infection. The present study extends this work to compare IgG1 and IgA isotype recognition of separated antigens by Western blot between the two communities. Comparison of age-dependent antigen recognition in the two communities shows that both qualitative and quantitative recognition by IgG1 antibodies is related to the current intensity of infection (as assessed by eggs per gram of faeces, epg). The magnitude of the IgA response to separated antigens of 16-17 kDa and 90 kDa exhibits a stronger trend to remain elevated in adults and to reflect the past experience of infection: IgA antibodies are present at significantly higher levels in adults from the high transmission area compared with those from the community with low levels of T. trichiura endemicity, despite infection levels in these age groups being of similar magnitude. This comparative study therefore, provides further evidence to support a role for IgA in acquired immunity to T. trichiura in areas of intense transmission.
Adolescent↗
Temporal changes in Trichuris trichiura infection intensity and serum isotype responses in children.
The present study describes Trichuris trichiura infections in a cohort of children over a period of approximately 5 years, and examines the relationships between changes in infection intensity and changes in parasite-specific isotype responses (measured by ELISA). The decrease in mean infection intensity with time was mirrored by time-dependent changes in IgG subclass responses, with IgA and IgE levels remaining relatively constant in the cohort. At the individual level, changes in infection intensity between the initial and final time-points correlated positively and significantly with changes in all isotype levels with the exception of IgA.
Animals↗
The age of infection with varicella-zoster virus in St Lucia, West Indies.
Sera from an age-stratified sample of 1810 people from the Caribbean island of St Lucia were tested for antibodies against varicella-zoster virus. The results indicate that very few infections occur in childhood, which agrees with clinical survey data from other tropical countries, but contrasts with the observed high case rate in children in temperate countries. The alternative hypotheses which may explain these results are discussed, and it is suggested that high ambient temperatures interfere with the transmission of the virus. Irrespective of the cause, the pattern of varicella incidence observed has important implications for any vaccination policy adopted in tropical countries.
Adolescent↗
Age-dependency of serum isotype responses and antigen recognition in human whipworm (Trichuris trichiura) infection.
The present study examines the age-dependency of parasite-specific isotype responses and antigen recognition profiles of individuals within a Trichuris trichiura endemic community, in order to evaluate the significance of serum antibodies as determinants of observed age-related patterns of infection intensity. A high degree of individual heterogeneity is observed in isotype responses to separated T. trichiura antigens by Western blot. Recognition by IgG1 antibodies exhibits marked age-dependency. The age-profiles of IgG1 responses to selected antigens of 16-17 kDa and 90 kDa molecular weight reflect the age-related changes in current infection intensity at the population level. Similarly, mean age patterns of IgG2 responses to a 90 kDa antigen, and mean IgG4 responses to a 16-17 kDa antigen reflect mean infection levels. IgG3 responses are negligible, and for methodological reasons, both IgE and IgM specificities are not presented. IgA responses to separated antigens of 16-17 kDa and 90 kDa, exhibit age-profiles which may suggest the development of an IgA-mediated acquired resistance to T. trichiura with age. IgA levels remain elevated throughout early adulthood, when infection intensity levels markedly decrease, supporting the hypothesis that IgA antibodies may be significant in generating the convex nature of the age-infection profile of T. trichiura.
Adolescent↗
The relationship between Trichuris trichiura transmission intensity and the age-profiles of parasite-specific antibody isotypes in two endemic communities.
The present study compares parasite-specific antibody responses in two Caribbean communities with high and low levels of Trichuris trichiura transmission. The age-dependency of antibody levels suggest that IgG1 and IgG2 levels relate to the current intensity of infection (as assessed by density of eggs in stool (e.p.g.) and reflect the age-intensity profile at the population level. IgG4, IgE and IgA levels persist into early adulthood and the subsequent decline is gradual. In the low transmission area, lower infection levels are reflected in lower parasite-specific antibody levels (of all isotypes) in the community as a whole. Despite a significantly greater past experience of infection in the high transmission area, antibody levels are not maintained at significantly higher levels throughout adulthood. The production of IgA appears to require a threshold for triggering, and a vigorous IgA response is maintained into early adulthood only in the high transmission village where peak intensity is greatest and the age-convexity of intensity is most marked. Experimental and theoretical studies focusing on the dynamic nature of host-helminth interactions in hosts exposed to high and low infection levels, and the putative role of acquired immunity, are discussed in relation to the data presented.
Adolescent↗
A molecular defect in human protoporphyria.
Protoporphyria is generally an autosomal dominant disease that is characterized clinically by photosensitivity and hepatobiliary disease and that is characterized biochemically by elevated protoporphyrin levels. The enzymatic activity of ferrochelatase, which catalyzes the last step in the heme biosynthetic pathway, is deficient in all tissues of patients with protoporphyria. In this study, sequencing of ferrochelatase cDNAs from a patient with protoporphyria revealed a single point mutation in the cDNAs resulting in the conversion of a Phe(TTC) to a Ser(TCC) in the carboxy-terminal end of the protein, F417S. Further, the human ferrochelatase gene was mapped to chromosome 18q21.3 by chromosomal in situ suppression hybridization. Finally, expression of recombinant ferrochelatase in Escherichia coli demonstrated a marked deficiency in activity of the mutant ferrochelatase protein and of mouse-human mutant ferrochelatase chimeric proteins. Therefore, a point mutation in the coding region of the ferrochelatase gene is the genetic defect in some patients with protoporphyria.
Amino Acid Sequence↗
The phagocyte oxidative metabolism function in ankylosing spondylitis.
The phagocyte oxydative metabolism function was measured using chemiluminescence in microamounts of whole blood in 15 ankylosing spondylitis (AS) patients (10 were B27 positive), and in 17 controls. It was obtained from cells at rest, and following stimulation (latex, zymosan, fMLP), with luminol and lucigenin as amplifiers. The maximal light intensity was significantly higher (P less than 0.01) in AS compared to the controls in resting cells as well as in those after stimulation. There was no difference between HLA-B27 positive or negative AS patients. The increase in oxidative metabolism of the phagocyte system in AS was more evident in the luminol dependent assay, suggesting an activation of the myeloperoxydase system.
Adolescent↗
Humoral immune responses in human infection with the whipworm Trichuris trichiura.
The humoral immune response to infection with Trichuris trichirua was investigated by ELISA and immunoblotting using human sera from the Caribbean island of St Lucia. Immunoblot analysis of the degree of cross-reactivity with the related trichuroid Trichinella spiralis and with the other commonly co-existent nematodes, Ascaris lumbricoides and Toxocara canis, was carried out using selected sera. The IgM, IgA, IgE, and IgG subclass antibody levels were measured in ELISA using a detergent solubilized extract of adult T. trichiura. The IgG and IgE responses were highly Trichuris specific. Anti-T. trichiura IgM responses were totally cross-reactive with A. lumbricoides and were completely ablated by pre-incubation of sera with Ascaris antigen. The IgG response was predominantly of the IgG1 subclass with a minimal IgG3 response. Only 1 person out of 130 tested had a detectable IgG3 response. The IgG2 response appeared to be directed primarily against carbohydrate or polysaccharide antigens as pre-treatment of the ELISA plates with poly-L-lysine was necessary before a response could be detected. These data are the first demonstration of human isotypic responses to infection with T. trichiura.
Animals↗
Age-dependency of infection status and serum antibody levels in human whipworm (Trichuris trichiura) infection.
This study examines the age-dependency of the relationships between human infection with whipworm (Trichuris trichiura) and parasite-specific antibody level measured by ELISA against an extract of adult worms after preincubation of the sera with Ascaris lumbricoides adult worm extract. The convex age-profile of parasite infection intensity is shown to be mirrored by an age-dependent change in age-class mean levels of IgG (all subclasses except IgG3), IgA, IgM and IgE. Mean antibody levels rise with increasing acquisition of infection in childhood and decline as the intensity of infection falls in adulthood. Immunoblot analysis of selected sera from different age-classes indicates that antigen recognition is similarly dependent on infection intensity. In individual children, antibody levels correlate positively with acquisition of infection, consistent with a simple model of antigen dosage specifying the magnitude of the humoral immune response. In adults, IgG4 correlates positively and IgA negatively with intensity of infection, suggesting involvement of these isotypes in functional roles of immune blockade or effector mechanisms, respectively.
Adolescent↗
Seroepidemiological study of the transmission of the mumps virus in St. Lucia, West Indies.
A seroepidemiological study of the prevalence of mumps virus specific antibodies reveals a pattern of endemic persistence on the island of St Lucia in the West Indies. In the unvaccinated population the proportion seropositive rose rapidly in the child age classes to attain a stable plateau close to unity in value in the teenage and adult age groups. The average age at infection was estimated to be between 3 and 4 years of age and the average duration of detectable levels of maternally derived antibodies was approximately 3 months. Analyses based on mathematical models of the transmission dynamics of the virus suggest that in excess of 75% of each cohort of 1- to 2-year-old children must be effectively immunized to eliminate mumps virus transmission. A mumps radial haemolysis test, developed for quantitative measurements of antibody, is discussed.
Adolescent↗