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.

Potential for diagnosis of intestinal nematode infections through antibody detection in saliva

The present study was the first to investigate the potential of saliva in community diagnosis of the major human intestinal nematode infections, Trichuris trichiura, Ascaris lumbricoides, and the hookworms. Immunoglobulin G (IgG) antibodies specific to parasite antigens were quantified in saliva samples of 187 individuals (all ages) from a St Lucian community, and 120 school-aged children from Tanga region, Tanzania, and relationships with current infection status (determined by numbers of parasite eggs in stool) were examined. For T. trichiura infection, the age relationships of parasite-specific salivary IgG antibodies mirrored those of infection intensity at the community level. Within both areas, children with current T. trichiura infection exhibited significantly higher anti-T. trichiura salivary IgG responses than uninfected children. Similar trends were apparent for A. lumbricoides and hookworm infections, though not to a level of statistical significance. Comparison of mean T. trichiura infection levels and antibody responses in age-matched children from St Lucia and Tanzania suggested that measurement of parasite-specific salivary IgG may have potential as a marker of transmission intensity at the community level.

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.

Effects of gallium chloride on changes in action potentials and contraction in guinea pig ventricular muscle

The electrophysiological effects of gallium chloride (Ga ) and its activity on arrhythmias induced by digitalis were investigated in guinea pig papillary muscle. KCl microelectrodes were used to record transmembrane electrical activity from Purkinje cells from the papillary muscle of guinea pig hearts during superfusion and electrical stimulation in vitro at 37 degrees C. Myocardial contractility was continuously monitored. Ga was superfused alone in cumulative concentrations(4.5 . 10(-5) to 3.6 . 10(-4) M). Arrhythmias were induced by a superfusion of Digitoxin (7.5 . 10 (-7) M). A superfusion of Ga (4.5 . 10(-5), 9 . 10(-5), 1.8 . 10(-4) M and 3.6 . 10(-4) M) was started 20 min later and maintained for 70 min. Ga alone produced a dose dependent reduction of action potential duration and contractility. Ga potentiated the decrease in the amplitude and duration of the action potential induced by Digitoxin. The incidence of arrhythmias was immediately reduced by two concentrations of Ga (4.5 . 10(-5) and 9 . 10(-5) M) in the digitalized papillary muscles. It is concluded that Ga inhibits calcium movements and has negative inotropic and antidysrhythmic effects.

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)

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.

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.

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.

[Effect of night medical guard on following day vigilance. Influence of hypnotic drug on recovery night and on the vigilance during the following day]

The consequences of sleep deprivation on vigilance and mood were evaluated in six healthy medical students the day after being on night duty and the following day, after recovering from a full night's sleep. Diurnal vigilance was studied using the Multiple Sleep Latency Test (MSLT) and mood was assessed on an anxiety self-evaluation scale. The study was conducted by means of a double-blind randomized trial to measure the effects of benzodiazepine (lormetazepam, 2 mg) compared to a placebo administered before the night recovery/full night's sleep. Sleep deprivation induced a significant decrease in vigilance the day following the night duty. Sleep latencies were shortened during the morning following the night of recovery/full night's sleep. The values obtained after administering the lormetazepam did not differ significantly from those obtained after administering the placebo. There were no considerable differences in the anxiety evaluation scores before and after the night of recovery/full night's sleep between the two sequences of the trial. This study suggests that a significant lack of sleep (a 36-hour sleep deficit) modifies diurnal vigilance over two nyctohemeral periods. Administration of benzodiazepine with a short half-life after occasional sleep deprivation does not change the reorganization of the sleep-waking cycle.

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.

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.

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.

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.

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.

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.

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.

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.

Effect of age and initial infection intensity on the rate of reinfection with Trichuris trichiura after treatment

The study examines the rate of re-acquisition of Trichuris trichiura infection after treatment in two populations, one of mixed age and the other of children with known pre-intervention infection intensity. A population living in a Caribbean village was treated with mebendazole and the rate of reacquisition of infection of four age classes (2-4, 5-10, 11-30, 30+ years) monitored over a 20-month period. The reinfection rate was higher in the child age-classes indicating either that children are more exposed to infection or that adults slowly develop a partially effective acquired immunity. A cohort of children (mean age 4.5 years) was separated into 3 intensity categories on the basis of expelled worm burdens and their rate of reacquisition of infection monitored over a 12-month period. The rate of reinfection was directly and positively associated with initial infection status. This may indicate that children with low intensity infections are consistently less exposed to infection or that they have effective immune responses. The latter conclusion, however, would imply that they had acquired this immunity early in life, and so appears to contradict the suggestion that resistance is only slowly acquired by adults. Reconciling these two conclusions may require more sophisticated immunological models than have been suggested previously for geohelminthiases.

Epidemiology and population dynamics of Ascaris lumbricoides and Trichuris trichiura infection in the same community

The gastrointestinal helminth infection status of an age-stratified sample from a single Caribbean community was assessed using anthelmintic expulsion techniques. The same sample was re-assessed in a similar manner after a 17 month period of re-infection. The age-prevalence profile of Ascaris lumbricoides was convex while that of Trichuris trichiura was asymptotic. The age-intensity profiles of both species were convex. These differing patterns are attributed to differences in the absolute worm burdens of the 2 species. The frequency distributions of infection intensity were similar for both species, and largely independent of host age. The basic reproductive rate of A. lumbricoides (Ro = 1-1.8) was similar to that recorded elsewhere and much lower than that of T. trichiura (Ro = 4-6), implying that the latter is intrinsically more resistant to control. Individual hosts were predisposed to high (or low) intensity infection with either species, although predisposition to both species simultaneously was not conclusively demonstrated. Further studies are required to determine the cause of these observations.

Sigmoidoscopy in children with chronic mucoid diarrhoea in rural St. Lucia

Sixty-nine per cent of a group of children with chronic mucoid diarrhoea who would not normally be seen in a tertiary health care facility had endoscopically demonstrable abnormality in the distal bowel, especially in the distal rectum. Sigmoidoscopy and punch biopsy of the rectum are safe procedures which can be undertaken in primary health care facilities. The inclusion of such investigations will facilitate the elucidation of the aetiology of chronic mucoid diarrhoea.

Prick tests in the diagnosis of anaphylaxis to general anaesthetics

Pre-charged prick tests and intradermal skin tests (two dilutions) were tested simultaneously in 79 patients using seven drugs (suxamethonium, gallamine, alcuronium, pancuronium, vecuronium, fentanyl and thiopentone) commonly administered during general anaesthesia. Fifty-seven of the patients had suffered anaphylaxis to anaesthetics: 50 had been tested previously (19.5 +/- 13.5 months) by intradermal tests (group 1) and seven were tested for the first time (group 2). Six patients had suffered a side effect during anaesthesia which was unrelated to anaesthetic agents (group 3) and 16 were control subjects (group 4). Prick and intradermal skin tests were simultaneously positive in 98 instances out of 553 (17.7%) and negative in 440 out of 553 (79.6%)--a correlation of 538 out of 553 (97.3%; P less than 0.001). In groups 1, 2 and 3 the correlation was 426 out of 441 (96.6%; P less than 0.001). In group 1, a correlation was observed between the diameters of the weals (r = 0.5; P less than 0.001) obtained by prick and intradermal skin tests, and between the diameters of the flares (r = 0.5; P less than 0.001).

Predisposition to Trichuris trichiura infection in humans

The study examines the distribution of Trichuris trichiura infection in a village community in St Lucia, West Indies. The infection intensity of the same age-stratified population was assessed (by drug expelled worm burden and faecal egg count) at the initiation of the study, and after 17 months of reinfection following treatment. The frequency distribution of worm numbers per person was similar at both periods of sampling. There was a significant correlation between the initial infection intensity of an individual, and the intensity acquired by the same individual following the 17 month period of reinfection. This relationship was observed in a broad range of host age classes. The study provides firm evidence that individuals are predisposed to heavy (or light) T. trichiura infection.

Age-related prevalence and intensity of Trichuris trichiura infection in a St. Lucian community

Age-related changes in the average worm burden and the prevalence of Trichuris trichiura infection, in a village community in St. Lucia, were examined by field studies based on worm expulsion techniques. Horizontal age-intensity profiles were convex in form with peak parasite loads occurring in the 2 to 15-year-old children. Prevalence is shown to be a poor indicator of changes in average worm load with age. Faecal egg counts (epg and epd) provide a qualitative measure of worm burdens since fecundity is shown to be approximately independent of worm load. The parasites were highly aggregated within the study community, with most people harbouring low burdens while a few individuals harboured very heavy burdens. Of the total parasite populations in the study sample, 84% were harboured by the 2 to 15-year-old children. Of those individuals harbouring 100 worms or more, 87% were in the 2 to 10-year-old age range. Crude estimates of population parameters (basic reproductive rate, 4-5; rate of reinfection, 90 year-1) suggest that the rate of reinfection is higher than for other helminth parasites of man. The control of morbidity and parasite transmission is discussed in the context of targeting drug treatment at the child segment of the study population.