Measurements of 106Ru in Sweden during the autumn 2017: Gamma-ray spectrometric measurements of air filters, precipitation and soil samples, and in situ gamma-ray spectrometry measurement

During the last days of September to the first days of October in 2017, a unique detection of ¹⁰⁶Ru was observed in air filters sampled at different locations in Sweden via the national air monitoring network. Furthermore, measurements of precipitation also showed the presence of ¹⁰⁶Ru. This initiated soil sampling and in situ gamma-ray spectrometry at one of the locations.

Prognostic value of colony-stimulating and colony-forming cells in peripheral blood in acute non-lymphoblastic leukemia

Colony-forming cells (CFC) and colony-stimulating activity (CSA) in peripheral blood cells have been studied before and repeatedly during treatment of 30 patients with acute non-lymphoblastic leukemia. WBC obtained after Isopaque-dextran separation were cultured in vitro by a double-layer agar technique. Before treatment 16 patients out of 30 had CSA and 22 out of 29 had CFC; both CSA and CFC were found in 15 patients. In follow-up studies during treatment, CSA was mainly unaffected during the leukopenic phase, while CFC were suppressed. No CFC were found at WBC counts below 900/mm3. This seems to imply that CFC are more sensitive to cytotoxic agents than colony-stimulating cells. Twelve patients entered remission; all of them had CSA and all the 11 who were investigated for CFC had CFC before treatment. Fourteen out of 18 non-responders lacked one or both types of cells. The presence of CSA and CFC in peripheral blood therefore appears to be a sign of favorable prognosis, while the absence of CSA and/or CFC implies lack of response to treatment.

Comparison of the performance of serological kits for Helicobacter pylori infection with European and Asian study populations

Most commercial kits for the detection of Helicobacter pylori were developed and validated with Western populations, and some have been found to perform less well with Asian populations. This study compared the performances of three serological kits with Swedish and Vietnamese peptic ulcer patients and asymptomatic individuals. The Pyloriset EIA-GIII and HM-CAP ELISA kits indicated that Asian populations had lower antibody titres to H. pylori than European populations. Despite the difference, the Pyloriset EIA-GIII kit performed well with Vietnamese peptic ulcer patients and population controls. The HM-CAP ELISA kit had a significantly lower performance with Asian populations that could not be improved by adjustments to the cut-off level. The Helicoblot 2.1 immunoblot kit performed equally well with Vietnamese and Swedish populations, although the response rate to the 35-kDa band was significantly lower with Vietnamese individuals.

Assessment of the cag pathogenicity island status of Helicobacter pylori infections with serology and PCR

The serological characterisation of Helicobacter pylori strains has been questioned, e.g., when the presence or absence of the cag pathogenicity island (PAI) is determined. This study compared CagA-reactive serum antibodies, assessed with immunoblot, with cag PAI status, as determined by PCR. CagA serology results were available for 101 individuals contributing 202 bacterial samples for cag PAI PCR. There was a high degree of correlation between the two methods (kappa coefficient, 0.82; 95% confidence interval, 0.68-0.97). Combined with suggested biological explanations for the discrepancies, this finding supports the application of well-evaluated serological assays in the assessment of the cag PAI status of H. pylori infections in clinical and epidemiological studies.

Long-term follow-up of Helicobacter pylori eradication therapy in Vietnam: reinfection and clinical outcome

AIM

To assess the long-term Helicobacter pylori reinfection rates, as well as the clinical outcome in peptic ulcer disease patients in Vietnam.

METHOD

At a 1-year evaluation of H. pylori eradication treatment in 226 peptic ulcer patients, long-term H. pylori status was assessed with serology and/or culture, peptic ulcer status by gastroscopy, and DNA-fingerprinting performed with random amplified polymorphic DNA and restriction fragment polymorphism.

RESULT

Follow-up was performed a mean 11 months after the post-treatment evaluation on day 30 after beginning of treatment. The overall reinfection rate was 23.5%, with 58.8% of the strains being identical to the pre-treatment isolates and 41.2% being different. Peptic ulcer was found in 22.9% of the reinfected patients and in 6.3% of the non-reinfected. At the long-term follow-up of successful eradication cases, 89.8% of the patients were free of peptic ulcer disease. The corresponding result was 58.7% in patients in whom H. pylori eradication failed.

CONCLUSION

Following successful H. pylori eradication, reinfection with H. pylori in patients in Vietnam was found to be higher than in industrialized countries but the long-term recurrence of peptic ulcer disease was still low. Helicobacter pylori eradication treatment is therefore of value also in developing countries as the rate of peptic ulcer disease was low at the 1-year follow-up.

Helicobacter pylori eradication in children and adolescents by a once daily 6-day treatment with or without a proton pump inhibitor in a double-blind randomized trial

AIM

To evaluate two simplified Helicobacter pylori eradication treatment alternatives for children and adolescents.

METHODS

Study subjects were identified by enzyme-linked immunosorbent assay and immunoblot in a family screening project. Helicobacter pylori infected 10-21 year olds were offered treatment, individuals with abdominal pain underwent upper endoscopy and those with peptic ulcers were excluded. Participants were randomized to either azithromycin 500 mg daily and tinidazole 500 mg two tablets daily in combination with lansoprasole 30 mg daily for 6 days (ATL-group) or with placebo (ATP-group). Urea Breath Test was performed at inclusion and after a minimum of 6 weeks after end of therapy.

RESULTS

In total, 131 individuals were randomized, of whom 31 (24%) had undergone upper endoscopy. Full compliance was achieved in 93% (122 of 131). The intention-to-treat eradication rate was 67% (44 of 66) and 58% (38 of 65) for the ATL- and the ATP-group, respectively.

CONCLUSION

The double-blind randomized clinical trial did not identify a simplified, successful once daily H. pylori treatment for children and adolescents. Thus, twice daily proton pump inhibitor (PPI)-based triple therapies for 7 days remain as the choice of treatment in children. Further, powerful and controlled studies are needed to elucidate the best treatment strategies for H. pylori eradication in this age group.

The importance of the level of metronidazole resistance for the success of Helicobacter pylori eradication

AIMS

To evaluate the role of antibiotic susceptibility for the treatment outcome of proton pump inhibitor-dependent and independent Helicobacter pylori eradication regimens.

METHODS

In a placebo-controlled clinical study of peptic ulcer patients with H. pylori infection, patients were randomized to receive lansoprazole, clarithromycin and tinidazole twice-daily, clarithromycin and tinidazole once-daily with lansoprazole or with placebo. Helicobacter pylori status was assessed by culture and antibiotic susceptibility by E-test minimal inhibitory concentration (MIC) in 205 clinical isolates.

RESULTS

Primary resistance to clarithromycin and metronidazole was 1 and 76%, respectively. In metronidazole susceptible strains eradication rates were similar at > 90% for all treatment groups (P = 0.49). With low-level metronidazole resistance (4 microg/mL < MIC < 256 microg/mL), eradication rates were similar at >75% (P = 0.80). The major difference was found at high-level metronidazole resistance (MIC >or= 256 microg/mL) with 95%, 58% and 21% eradication in the lansoprazole, clarithromycin and tinidazole twice-daily, lansoprazole, clarithromycin and tinidazole once-daily and placebo, clarithromycin and tinidazole once-daily groups, respectively (P < 0.001).

CONCLUSION

In the absence of antibiotic resistance, a once-daily therapy of only clarithromycin and tinidazole can achieve a high rate of H. pylori eradication. Such a combination could offer a simpler and cheaper treatment option for developing countries. The standard, twice-daily proton pump inhibitor-based triple therapy was shown to be efficient in H. pylori eradication even in the presence of high-level metronidazole resistance.

Unexpected decrease with age of Helicobacter pylori seroprevalence among Swedish blood donors

Blood donors are often used as proxies for the general population in studies of Helicobacter pylori epidemiology. Our aim was to test if the age-specific seroprevalence rates among blood donors match with the corresponding rates in a random population sample. This descriptive study was based on sera obtained from 3,502 blood donors representing all Swedish counties and cities. An age-stratified random population sample of 1,030 from Stockholm County served as comparison. Sera were analyzed by an in-house enzyme-linked immunosorbent assay for H. pylori immunoglobulin G antibodies. In the population sample, we found the expected increase with age in the seroprevalence of H. pylori infection. This was true also among young blood donors, while the prevalence-by-age curve showed a deflection downward among blood donors who are >/= 50 years of age. In this age group, the probability of being seropositive was reduced by 73% (95% confidence interval [CI], 63 to 81%) relative to the population sample. Overall, the adjusted odds ratio for H. pylori seropositivity among blood donors was decreased by 43% (95% CI, 28 to 55%). Thus, it appears that blood donors who are H. pylori seropositive selectively disappear from the blood donor cohort. We speculate that H. pylori-seropositive blood donors may tolerate repeated bleedings less well than do noninfected individuals and/or that the general well-being among those who are infected may be somewhat impaired. Our unexpected observation indicates that blood donors may be less suitable as proxies for the general population in analytic studies of H. pylori infection and that the underlying cause needs further study.

Helicobacter pylori eradication and peptic ulcer healing: the impact of deleting the proton pump inhibitor and using a once-daily treatment

AIM

To compare cheaper and simpler once-daily regimens, with and without a proton pump inhibitor, with standard, twice-daily, triple therapy.

METHODS

A randomized, placebo-controlled, treatment trial in Vietnam allocated 296 Helicobacter pylori-infected patients with peptic ulcer of >or= 5 mm to one of three regimens: (i) twice-daily: lansoprazole 30 mg, clarithromycin 250 mg and tinidazole 500 mg; (ii) once-daily: lansoprazole 60 mg, clarithromycin 500 mg and tinidazole 1000 mg; (iii) once-daily: placebo, clarithromycin 500 mg and tinidazole 1000 mg. H. pylori status was assessed by culture and immunoblot, ulcer healing by endoscopy and side-effects by structured questionnaires.

RESULTS

Per protocol eradication (N = 256) was higher with standard therapy (87%) than with once-daily therapy (72%), and both were better than once-daily therapy without proton pump inhibitor (39%). Per protocol ulcer healing after standard therapy (83%) was not significantly better than that after once-daily therapy (73%), but better than that after therapy without proton pump inhibitor (65%). Side-effects were reported at similar rates in all groups.

CONCLUSIONS

Proton pump inhibitor was needed for optimal eradication and ulcer healing. Twice-daily administration showed improved success rates when compared with once-daily therapies. Peptic ulcer healing was achieved even in patients treated with antibiotics only, confirming the central role of H. pylori in the pathophysiology of peptic ulcer disease.

Community health care nursing in Rajasthan. A registered nurse's perspective

This study focused on the great shortage of registered nurses (RNs) in primary health care in Rajasthan, India. It dealt especially with the nurses' own opinions about working in primary health care and their reasons for not working in it. Nurses at different levels in the health care organization were interviewed. The study was based on interviews with six RNs individually, three groups of six to eight nursing students each, and three policy-making chief nurses individually. The Minister of Health in Rajasthan also participated in the study. The study showed that the reasons for the lack of RNs in community health care were as follows: a government policy decision to place less educated nurses in the communities; the great shortage of nurses in general; the system whereby a nurse is not able to choose her/his place of work; unwillingness on the part of the nurses to work in community health care because of the great security problems; lack of support from authorities and lack of equipment. In general, community health care nursing as a work area was despised by society at large in Rajasthan.

Refinement of the 14C-urea breath test for detection of Helicobacter pylori

BACKGROUND

Helicobacter pylori is recognized as the main etiological factor for chronic gastritis, peptic ulcer and possibly also gastric malignancies. A 14C-urea breath test was successively refined to correctly diagnose the presence of H. pylori.

METHODS

After intake of a 14C-urea cocktail, 14CO2 in breath was trapped in benzethoniumhydroxide/ethanol. Serology by ELISA, followed by Western blot, was used as reference method for confirmation of presence or absence of H. pylori.

RESULTS

Breath measurements at 10 and 20 min were determined to be optimal for diagnostic purposes. With 2.5 microCi of 14C-urea, a sensitivity of 86% and specificity of 100% was obtained for the 10-min values. Corresponding data for the 20-min values were 86% and 99%, respectively. When 50 mmol L(-1) citric acid was added to the 2.5 microCi 14C-urea cocktail, separation between positive and negative results became more distinct along with improved sensitivity of 91% and specificity of 100%. As the isotope amount was reduced to 1.0 microCi in the citric acid-containing cocktail, a sensitivity of 93% and specificity of 100% were obtained at both 10 and 20 min.

CONCLUSION

Diagnostic urea breath test has a high concordance with H. pylori serology, combining ELISA and Western blot. Stepwise refinements proved the optimal urea breath test cocktail to include 1.0 microCi 14C-urea in citric acid solution with breath measurement at 10 min.

Helicobacter pylori infection in Swedish school children: lack of evidence of child-to-child transmission outside the family

BACKGROUND & AIMS

Helicobacter pylori infection is mainly acquired in early childhood, but the exact routes of transmission remain elusive. To distinguish between risks of intrafamilial and extraneous child-to-child transmission, we studied H. pylori seroprevalence among Swedish school children with varying family backgrounds.

METHODS

In a cross-sectional study, 695 of 858 (81%) 10-12-year-olds in 36 school classes in Stockholm donated blood and answered a questionnaire. Infection was detected by enzyme-linked immunosorbent assay and confirmed by immunoblot and urea breath test.

RESULTS

Overall, 112 (16%) children were infected. The seroprevalence was 2% among 435 children with Scandinavian parents and 55% among 144 children with origin in high prevalence areas (Middle East and Africa). Among children born in Scandinavia, the odds ratios (adjusted for gender, socioeconomic status, and family size) for being seropositive were 39.1 (95% confidence interval, 16.7-91.3) and 5.6 (1.8-17.3) when having parents born in high and medium prevalence areas, respectively, relative to children with Scandinavian parents. Importantly, the prevalence of infection among the classmates was not a risk factor for H. pylori infection.

CONCLUSION

Our data indicate that intrafamilial transmission is far more important than child-to-child transmission outside the family. The H. pylori prevalence in the parental generation may be a crucial determinant for the child's risk of contracting the infection.

The accuracy of serologic diagnosis of Helicobacter pylori infection in school-aged children of mixed ethnicity

The present study evaluated two non-invasive diagnostic methods for H. pylori infection in children, i.e. an in-house ELISA using sonicated Campylobacter jejuni antigen for absorption of cross-reacting antibodies and an immunoblot kit (Helico Blot 2.0, Genelabs, Singapore). 13C -Urea breath test (13C-UBT) was used as reference

METHOD

Sera and questionnaires were collected from 695/858 (81%) Swedish school children with mixed ethnic backgrounds within a cross-sectional, community-based study. Of 133 children with an ELISA OD value of > or = 0.1, all were screened with immunoblot and 107 made a 13C-UBT. The negative controls were 34/37 children from three school classes with an ELISA OD value of < 0.1 and volunteering for a 13C-UBT. An adjusted cut-off level for the ELISA of OD value 0.22 resulted in a sensitivity of 97.8%, a specificity of 95.8% and a concordance index of 97.2%. The Helico Blot 2.0 had a sensitivity of 97.8%, a specificity of 93.8% and a concordance index of 96.5%. The best concordance was seen for the 26.5 kDa (98.6%), 30 kDa (95.7%) and 19.5 kDa (91.5%) antigens. The corresponding concordance index for CagA was 78%, for VacA 73.8% and for the 35kDa antigen 68.8%. A significant difference in the distribution of the 19.5 and 26.5 kDa bands but not of CagA/VacA was noted by ethnic background. With an adjusted cut-off level for the enzyme-linked immunosorbent assay (ELISA), both non-invasive methods were found to have an adequate performance in a pediatric population. The differences in antibody response patterns by ethnic background represent a caveat in the interpretation of serological studies.

Impact of a vaccination campaign on adult immunity to diphtheria

OBJECTIVES

to raise the level of immunity to diphtheria in the adult population of Stockholm by a vaccination campaign. The rationale behind the campaign, conducted during 1995-1996, was the re-emergence of epidemic diphtheria in the countries of the former Soviet Union and earlier surveys of immunity to diphtheria showing low levels of protection in adults.

DESIGN AND MAIN OUTCOME MEASURES

the impact of the vaccination campaign was measured by recording the age and sex of vaccinees, the type and number of vaccine doses given and any side-effects. The effect on immunity was evaluated in 1998-1999 by measuring the neutralising antibodies in blood samples from 1863 inhabitants, chosen by random stratified sampling. Vaccines and vaccinations: three doses of diphtheria (D) or diphtheria-tetanus (DT) vaccine were given to those without documented previous vaccination; others received a booster dose. The DT vaccine, with the D component purified before toxoiding, contained 15 Lf of D and 7.5 Lf of T per ml, and was given in 0.5 ml doses for the two priming doses and 0.25 ml as booster.

RESULTS

184969 doses of D or DT vaccine were given to 99939 individuals. Of the vaccinees, 65% were 50 years of age or older and 60% were women. The highest rates of reported local reactions were 1.8-5.4% and of systemic reactions, such as fever, 0.2-0.8%. The campaign resulted in a significant increase in antitoxin concentrations in the age cohorts targeted, and especially in women, less well protected than men.

CONCLUSIONS

a vaccination campaign, targeting the adult part of a population, can result in a major improvement in immunity to diphtheria with only a few and minor side-effects with a DT vaccine where the D component was purified prior to toxoiding. Extending national immunisation programmes to include adults would, however, seem preferable.

A European multicenter study of immunoblotting in serodiagnosis of lyme borreliosis

A European multicenter study of immunoblotting for the serodiagnosis of Lyme borreliosis showed considerable variation in results obtained from tests with a panel of 227 serum samples. Six laboratories used different immunoblot methods, and a wide range of bands was detected in all the assays. Multivariable logistic regression analysis of data from individual laboratories was used to determine the most discriminatory bands for reliable detection of antibodies to Borrelia burgdorferi sensu lato. These bands were used to construct individual interpretation rules for the immunoblots used in the six laboratories. Further analysis identified a subset of eight bands, which were important in all the laboratories, although with variations in significance. Possible European rules, all closely related, were formulated from these bands, although there was no single rule that gave high levels of sensitivity and specificity for all the laboratories. This is a reflection of the wide range of methodologies used, especially the use of different species and strains of B. burgdorferi sensu lato. The panel of European rules provides a framework for immunoblot interpretation which may be adapted in relation to the characteristics of Lyme borreliosis in local areas.

Booster effect of low doses of tetanus toxoid in elderly vaccinees

In order to improve the immunity to diphtheria, the recommended booster dose of diphtheria/tetanus vaccine for adults in Sweden was changed in 1986 from 0.5 ml of tetanus vaccine with a small diphtheria dose to 0.25 ml of a diphtheria/tetanus vaccine containing 7.5 Lf tetanus toxoid and 30 Lf diphtheria toxoid/ml. This change resulted in an increase in the dose of diphtheria toxoid from 0.5 Lf to 7.5 Lf, but a decrease in the recommended booster dose of tetanus toxoid from 3.75 Lf to 1.9 Lf. The aim of the present study was to investigate whether this lower dose of tetanus toxoid was also sufficiently protective for elderly people. Two hundred adults (median age 76 years, range 60-92 years) with no history of tetanus vaccination during the past 10 years volunteered for the study. One hundred two vaccinees were inoculated with 1.9 Lf tetanus toxoid (0.25 ml) and 98 with 3.75 Lf tetanus toxoid (0.5 ml). Paired serum samples were analysed by the toxin-binding inhibition assay. Side effects were few and mild, without significant differences between the groups. Response rates were similar, with the 3.75 Lf dose eliciting a marginally higher antitoxin response. The prevaccination geometric mean titre was the same for both groups: 0.03 IU/ml. Postvaccination geometric mean titres were 1.18 IU/ml for the 3.75 Lf group and 1.93 IU/ml for the 7.5 Lf group, respectively (difference not significant). Forty-seven percent of the vaccinees had a prevaccination titre of < or =0.01 IU/ml. Postvaccination, 85% had a titre >0.01 IU/ml. Booster vaccination with tetanus vaccine containing only 1.9 Lf of tetanus toxoid was thus found to induce an excellent immune response in elderly people, with few side effects resulting.

Signal transduction-mediated adherence and entry of Helicobacter pylori into cultured cells

BACKGROUND & AIMS

An ability to invade host cells could be a means for Helicobacter pylori to achieve resistance to antibiotic therapy. The aim of this study was to investigate the mechanisms involved in adherence and entry of H. pylori into cultured cells.

METHODS

Coinfection with Yersinia expressing mutant or wild-type YopH tyrosine phosphatase was used. Genistein and cytochalasin D were used as inhibitors of adherence and entry; entry was monitored by a gentamicin-protection assay. Target cells were AGS cells and a beta1-integrin-deficient cell line with its corresponding beta1-integrin-expressing transfectant.

RESULTS

H. pylori induced phosphorylation of 125-130-kilodalton proteins, similar in size to the target proteins of Yersinia YopH. Adherence of H. pylori was inhibited by Yersinia organisms expressing enzymatically active YopH but not by inactive YopH. Adherence and entry of H. pylori was considerably higher with beta1-integrin-transfected cells than with beta1-integrin-deficient cells. Antibodies directed against alpha5- and beta1-integrin chains reduced adherence to the alpha5beta1-integrin-expressing gastric cell line AGS. Entry was inhibited by both cytochalasin D and genistein. Entry, but not adherence, was higher for 2 type I strains than for a type II isolate.

CONCLUSIONS

Invasion of gastric epithelium via an integrin-mediated pathway could contribute to the ability of H. pylori to establish persistent infection.

Clinical symptoms and social factors in a cohort of children spontaneously clearing Helicobacter pylori infection

In a cohort study of 305 Swedish children, repeated blood samples and structured questionnaires were obtained from 6 mo to 11 y of age. Of the 40 children seropositive for Helicobacter pylori in one or more samples, 32 (80%) had cleared the infection by 11 y of age. No association was found between H. pylori seropositivity at any time and reported antibiotic consumption, size of home and family, type of day-care, history of atopic disease, length of breastfeeding or peptic ulcer disease in the family. Girls reported more (p = 0.002) unspecified abdominal pain during childhood than boys, but the difference in H. pylori infection rate (15/150, 10% for boys and 25/144, 17% for girls) was not significantly different (p = 0.09). Unspecified abdominal pain during childhood was reported more often (OR adjusted for gender = 2.2, 95% CI = 1.0-4.4, p = 0.04) for the children seropositive at some point (17/39, 44%) than for the seronegative children (54/217, 25%). RAP at 11 y of age was more often reported by the 9/36 (25%) children seropositive at some time in life than by the 23/172 (13%) seronegatives, but the difference was not statistically significant (OR adjusted for gender = 2.0, 95% CI = 0.8-4.6, p = 0.1). The study shows that H. pylori seropositivity was associated with a parental report of unspecified abdominal pain during childhood. Also, a history of unspecified abdominal pain was more common (OR = 51.6, 95% CI = 15.6-220, p < 0.001) in children reporting RAP at 11 y of age.

Subcutaneous versus intramuscular injection for booster DT vaccination of adolescents

The importance of the injection technique in booster vaccination was investigated in an open randomized study with 252 10-year-old Swedish school-children receiving routine DT vaccination either by subcutaneous or by intramuscular route in the upper arm. The adolescents had previously been primed with DT vaccine at 3, 5 and 12 months of age. Adverse reactions, monitored for 2 weeks, showed the same low rates for systemic reactions in both groups, while the intramuscular administration gave significantly less redness (p < 0.001), swelling (p < 0.001), itching (p < 0.01) and pain (p < 0.05). These reactions were also of shorter duration (p < 0.01 to p < 0.001). Girls were found to have more pain and itching than boys (p < 0.001). No significant differences in antibody responses between the two administration routes were found in the 99 samples drawn 2 weeks after the booster. However, girls were found to have a lower response to diphtheria toxoid than boys (p = 0.009). Local reactions to a booster can thus be significantly reduced by choice of injection technique, which may be necessary if increased dosages and/or further valences are to be given to adolescents and adults.

A ten year follow-up after immunization with a two component acellular pertussis vaccine

OBJECTIVES

To investigate the duration of antitoxin response and immunity to pertussis 10 years after priming with either two or three doses of a two component acellular pertussis vaccine or with three doses of a whole cell vaccine and then boostered with the acellular vaccine.

SUBJECTS

At 11 years of age 207 of 304 (68%) children of the original cohort returned for a blood sample and 262 (86%) participated by answering a questionnaire.

METHODS

Neutralizing antibodies to pertussis toxin (antitoxin) were analyzed by the Chinese hamster ovary cell assay. Clinical pertussis and pertussis exposure were investigated by a structured questionnaire.

RESULTS

Measurable antitoxin was found in 77% of the samples, with no differences by type of vaccine or by the number of doses given for priming. A significant decrease of antibody concentration (P<0.001) was noted from the previous recall at 4 years of age, and significant titer rises were found for 14% of the children, irrespective of known exposure. Confirmed pertussis during follow-up, as defined in the study, was reported for 14 of 262 (5%) children.

CONCLUSIONS

The study showed that antitoxin concentrations are maintained in a situation of endemic pertussis and indicated that the long term protection after an acellular booster was good, irrespective of type of vaccine or the number of doses of acellular vaccine given for priming.

Pertussis IgE and atopic disease

BACKGROUND

Pertussis toxin (PT) stimulates IgE production in animals, and pertussis vaccination and whooping cough may have similar effects in man.

METHODS

We analyzed IgE responses to PT (PT-IgE) in sera from children primarily immunized with three doses of either an acellular 2- or 5-component vaccine, or a whole-cell (Wc) pertussis vaccine, and in children after whooping cough. The study comprised 50 children with both atopic disease and positive skin prick test, 99 nonatopic controls, and 40 children with verified pertussis.

RESULTS

Immunoglobulin E antibodies against PT were demonstrated in 19% and 24% of sera from vaccinated children at 7 and 12 months, respectively, and in 9% at 2.5 years. At 7 months, PT-IgE was more common after vaccination with acellular (24%) than with the Wc vaccine (3%, P = 0.02). PT-IgE was also more common (P = 0.001) after vaccination in children classified as atopic (36%) than in the control group (10%). Thirty percent of the children with pertussis had PT-IgE, more often so in atopic than nonatopic children (P = 0.02).

CONCLUSIONS

Transient production of PT-IgE seems to be common after primary pertussis immunization with acellular vaccines, and after whooping cough, particularly in atopic subjects.

Safety and immunogenicity of a combined diphtheria-tetanus-acellular pertussis-inactivated polio vaccine-Haemophilus influenzae type b vaccine administered at 2-4-6-13 or 3-5-12 months of age

METHODS

In an open randomized study we compared the safety and immunogenicity of two schedules for priming and booster vaccinations of infants. A pentavalent combination vaccine, including a lyophilized Haemophilus influenzae type b-tetanus toxoid conjugate vaccine reconstituted with a liquid diphtheria, tetanus, acellular pertussis (pertussis toxoid and filamentous hemagglutinin) and inactivated polio vaccine (DTaP-IPV/Act-HIB; Pasteur Mérieux Connaught, Lyon, France) was administered to 236 Swedish infants either at 2, 4 and 6 months or at 3 and 5 months, and a booster dose was administered 7 months after the last primary dose. Adverse events were monitored by diaries for 3 days after each vaccination and by questions at the ensuing visits. Antibodies against the different vaccine components were analyzed after the primary series of vaccinations, before and after the booster injections.

RESULTS

There were no serious adverse reactions, and the rates of febrile events and local reactions were low in both groups. The three dose primary schedule induced higher geometricmean concentrations for all antigens than did the two dose schedule, but there were no differences between the groups in proportions with protective antibody titers against diphtheria, tetanus, Hib and polio or in proportions with certain defined levels of pertussis antibodies. Prebooster results showed a similar pattern, with the exception that the group primed with three injections showed higher proportions of infants with detectable antibodies against polio-virus types 1 and 3. After booster vaccinations there were no differences between the two schedules in geometric mean or in proportions with antibodies above defined antibody concentrations, indicating effective priming from both primary series of vaccinations. Conclusion. The combined vaccine DTaP-IPV/ Act-HIB vaccine was equally safe and immunogenic when administered according to both time schedules studied.

Type I Helicobacter pylori shows Lewis(b)-independent adherence to gastric cells requiring de novo protein synthesis in both host and bacteria

Type I Helicobacter pylori strains frequently recognize the Lewisb (Leb) blood group antigen. This binding property and expression of the Leb oligosaccharide were required for adherence to fixed normal or pathologic gastric tissue. In contrast, both type I and type II strains adhered to cultured cells in the absence of the Leb epitope. For the gastric cell line AGS, adherence was significantly higher when viable type I strains were allowed to interact with viable AGS cells compared with fixed cells. The observation that chloramphenicol and cycloheximide, inhibitors of bacterial and eukaryotic protein synthesis, respectively, significantly reduced adherence of type I but not type II isolates suggests that in type I strains, adherence depends on the up-regulation of one or more host cell receptors triggered by the bacterium.

Capture EIA for determination of IgE to diphtheria and tetanus toxins in comparison to RIA

A capture IgE assay in EIA with diphtheria toxin and tetanus toxoid as model systems was developed and evaluated in relation to RIA in a DT booster study. The EIA and the RIA gave very similar results, although the EIA determined IgE over a wider range of concentrations, without interference by other subclasses. The comparison to the capture EIA indicated that the RIA gave more reliable results when a toxin as antigen. Weak correlations between local side effects and IgE responses and differences between vaccine groups were noted by RIA but not by EIA, which correlated better with the clinical findings.

The European Union Concerted Action World Wide Web site for Lyme borreliosis

This web site (URL http://www.dis.strath.ac.uk/vie/LymeEU/) provides information on Lyme borreliosis for physicians, scientists, health care workers, veterinarians and students. It consists of a review of the spirochaetes, vectors, reservoir hosts, diagnosis, treatment, epidemiology and prevention of the disease, as well as an account of the activities of EUCALB.

European Lyme borreliosis clinical spectrum

At a series of meetings, involving 27 clinicians from 11 countries, case definitions for the diagnosis of Lyme borreliosis in Europe were agreed and are presented here, with appropriate serological criteria, as a diagnostic guide. In a separate study questionnaires directed to clinicians were used to collect information on clinical aspects and risk factors of Lyme borreliosis. Data on the number of Lyme borreliosis patients seen by physicians indicated a low prevalence of the disease in western Europe and a relatively high prevalence in eastern Europe. The most commonly encountered symptom was erythema migrans, followed by neurological manifestations. Cardiac problems were rare. Tick bite was strongly associated with Lyme borreliosis, but the only other significantly associated risk factor was the pastime of gardening.

Epidemiology of European Lyme borreliosis

Lyme borreliosis occurs throughout Europe and is particularly prevalent in the east. In a small proportion of untreated cases serious sequelae may occur, but Lyme borreliosis alone does not cause death. Clinical and serological diagnosis can still be problematic and the various genomospecies may cause different disease manifestations as well as differing immunological responses. However, considerable progress has been made in standardising case definitions and serological testing and interpretation. Few countries have official reporting systems for Lyme borreliosis and most figures on incidence are extrapolated from serodiagnosis data and seroprevalence studies. Geographical variations in incidence seem to correlate with the prevalence of infected ticks, which are mainly associated with varied deciduous forest. The complex ecology of Lyme borreliosis makes it difficult to implement preventive measures, so improving public knowledge of risk factors and methods for personal protection remain the best option at present.

Lyme borreliosis awareness

A Lyme borreliosis information leaflet has been produced to promote awareness amongst the general public. It was designed to provide a framework for similar material throughout Europe and complements a questionnaire produced to measure awareness of Lyme borreliosis. This questionnaire can be used to determine the impact of educational campaigns using material such as the leaflet. Feasibility studies showed that the questionnaire successfully highlighted predictable differences between sample groups and also that the leaflet performed well in increasing knowledge in low-awareness groups.

Immunoglobulin E and G responses to pertussis toxin in children immunised with adsorbed and non-adsorbed whole cell pertussis vaccines

The IgE and IgG responses to pertussis toxin were measured in blood samples from 70 children (age 1.5-2.9 years) after primary immunisation with either a non-aluminium adsorbed, whole cell vaccine (n = 34) or an aluminium adsorbed whole cell vaccine (n = 36). Two years later, they received a booster immunisation with either the non-adsorbed (n = 24) or the aluminium adsorbed vaccine (n = 14). Neutralising antibodies to pertussis toxin were higher (P < 0.05) after the three priming doses of the adsorbed vaccine than of the non-adsorbed vaccine, although both groups showed > 90% seropositives after the third dose. IgE antibodies to PT (PT-IgE) were detected in samples from 11/52 children after completed primary immunisation and the levels were low (median < or = 0.1 PRU ml-1) in both groups. No significant differences between the groups were found. PT-IgE levels did not increase after the booster injection. Thus, the aluminium content of the whole cell vaccines influenced the IgG response but not the IgE responses to pertussis toxin. The high rates of PT-IgE responses noted after a booster dose of acellular or whole cell pertussis vaccine to children primed with acellular vaccine in previous studies can therefore be mainly ascribed to the nature of the priming vaccine rather than the aluminium adjuvant.

Immunoglobulin E and G antibodies two years after a booster dose of an aluminium-adsorbed or a fluid DT vaccine in relation to atopy

Immunoglobulin E and G levels to diphtheria and tetanus toxoids were investigated two years after a DT booster with either an adsorbed or a nonadsorbed, fluid vaccine, given at 10 years of age. Although IgE levels had declined, detectable IgE to diphtheria and tetanus toxoids were still found in 82% and 67% of samples, respectively, to be compared to prebooster levels of 3-14% and postbooster levels of 92-94%. The IgG levels had also declined but remained at equal and high levels in both the adsorbed and the fluid vaccine groups. The prevalence of allergic symptoms was similar in the two vaccination groups. Thus, the study showed an unexpected, long duration of the IgE responses elicited by a booster dose of DT vaccine. The booster dose also induced a durable, high IgG antibody response to both the adsorbed and the fluid vaccine.

A population-based seroepidemiologic study of human granulocytic ehrlichiosis and Lyme borreliosis on the west coast of Sweden

Ehrlichioses are emerging infections in the United States. Human granulocytic ehrlichiosis (HGE) and Lyme borreliosis (LB) are acquired after Ixodes ricinus-complex tick bites. An ongoing seroepidemiologic study of the 185 of the 356 permanent residents of the Koster Islands in Sweden was expanded to include ehrlichioses. Ehrlichial antibodies were measured by IFA using Ehrlichia equi and Ehrlichia chaffeensis. Borrelia burgdorferi IgG ELISA-seropositive subjects were confirmed by Western blot. E. equi and E. chaffeensis antibodies (titer > or = 80) were found in 21 (11.4%) and 2 (1.1%) of 185 samples, respectively. Antibodies to B. burgdorferi were found in 25 (13.5%) of 185. Six persons were seropositive for both HGE and LB. Among data from questionnaires, clinical symptoms, antibiotic treatments, or tick bites were not more frequent in E. equi- or B. burgdorferi-seropositive than -seronegative persons. The seroprevalence of HGE was similar to that of Lyme borreliosis. Prospective studies of European HGE are needed.

Seroepidemiology of Helicobacter pylori infection in a cohort of children monitored from 6 months to 11 years of age

A cohort of Swedish children was monitored from 6 months to 11 years of age. Immunoglobulin G (IgG) and IgA antibodies to Helicobacter pylori were measured in 1,857 serum samples, drawn at the ages of 6, 8, 10, 18 months and 2, 4, and 11 years. Of the 294 children, 40 (13.6%) were found to have been infected at some time. However, at 11 years of age, only 6 of 201 (3%) children were seropositive. The highest seroprevalence of positive results, 10%, was found at 2 years of age, and the highest incidence of 13.3% could be calculated for the period between 18 months and 2 years of age. There were no confirmed additional cases for children between 4 and 11 years of age. Infection with H. pylori thus occurs at an early age in a developed country (as well as in developing countries), and spontaneous clearance seems to be common.

Bordetella pertussis serotype of clinical isolates in Sweden during 1970-1995 and influence of vaccine efficacy studies

During the years 1970 to 1995, the serotypes of collected clinical isolates from the different regions of Sweden were examined. Vaccination using whole-cell pertussis vaccine decreased during the year preceding cessation of general vaccination of children in 1979. Although the total number of clinical isolates examined was limited up to 1978 compared to later years, serotype 1, 2, 3 clinical isolates generally predominated. During periodical pertussis outbreaks, serotype 1, 3 strains were isolated, the proportion of which was about equal to that of serotype 1, 2, 3 isolates. Following cessation of general vaccination in 1979, the proportion of both serotypes 1, 2, 3 and 1, 3 isolates gradually diminished, together contributing about 20 percent of the total number of isolates in 1995. Clinical isolates of serotype 1, 2 were identified in the year 1977, just before cessation of general vaccination in Sweden using whole-cell vaccine. Since then, this serotype has gradually increased to over 80 percent of total isolates in 1995, possibly indicating that the use of whole-cell pertussis vaccine was effective against this serotype or that the vaccine influenced serotype expression. Vaccine efficacy studies conducted in Sweden during 1986-87 using one and two-component vaccines (BIKEN) and in 1994-95 using two-component (SmithKline Beecham Pharmaceuticals) and five-component (Connaught Laboratories, Ltd.) vaccines are examined with the object of studying whether the vaccines showed any influence on the different serotypes of B. pertussis causing disease.

The diagnostic value of enzyme immunoassay and immunoblot in monitoring eradication of Helicobacter pylori

55 patients with severe ulcer disease and H. pylori infection, successfully treated with antimicrobials, were followed-up with repeated blood samples for up to 32 months. Sera were analysed by enzyme immunoassay (EIA) for IgG and IgA antibodies and by IgG immunoblot. The EIA for IgG antibodies showed a high sensitivity (100%), while IgA antibodies above the cut-off level were found in 55% of the patients. At a median of 77 days after onset of treatment, approximately 50% of the patients showed a significant decrease (> or = 50%) of IgG or had titres below the cut-off level. All patients but 1 had a significant decrease of IgG after 6-12 months. The decrease was slower for IgA. The H. pylori-specific 116 kDa and 19.5 kDa bands were found in all pre-treatment samples, but the decrease in median intensity of the bands was slower than for the IgG EIA. In the 32-months post-treatment samples, both bonds had an intensity still above 50% of the pre-treatment value. The study showed that the IgG EIA is a useful method for monitoring eradication of H. pylori. Immunoblot can detect previous H. pylori infection in EIA negative Individuals.

H2O2-driven reduction of the Fe3+-quin2 chelate and the subsequent formation of oxidizing species

The objective of this study was to compare effects of quin2 and EDTA in iron-driven Fenton-type reactions. Seven different assays for detection of strong oxidants were used: the DMSO, deoxyribose, benzoate hydroxylation, and plasmid DNA strand breakage assays, detection of 8-oxo-deoxyguanosine in deoxyguanosine mononucleosides and calf thymus DNA, and electron spin resonance with the spin-trap (4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) in the presence of ethanol or DMSO. With H2O2 and Fe3+, quin2 generally strongly increased the formation of reactive species in all assays, whereas with EDTA the results varied between the assays from barely detectable to highly significant increases compared to H2O2 and unchelated Fe3+. We found that the species produced in the reaction between Fe3+-quin2 and H2O2 behaved like the hydroxyl radical in all assays, whereas with Fe3+-EDTA no clear conclusion could be drawn about the nature of the oxidant. The effect of quin2 on the formation of oxidants on Fe2+ autoxidation, varied from generally inhibiting to slightly promoting, depending on the assay used. EDTA had a promoting effect on the amount of oxidant detected by all but one assay. None of the autoxidation systems produced DMSO or ethanol radical adducts with 4-POBN. In the presence of either chelator, H2O2, and Fe2+ DMSO and ethanol radical adducts of 4-POBN were produced. Using the Fe2+ indicator ferrozine, evidence for direct reduction of Fe3+-quin2 by H2O2 was found. Superoxide anion radical appeared to be less efficient than H2O2 as reductant of Fe3+-quin2 as addition of superoxide dismutase in the ferrozine experiments only decreased the amount of Fe2+ available for Fenton reaction by 10-20%. The main conclusions from our study are that the reduction of Fe3+-quin2 can be driven by H2O2 and that Fe2+ in the following oxidation step produces a species indistinguishable from free hydroxyl radical.

Endotoxemia in febrile patients with hematological malignancies. Relationship of type of bacteremia, clinical findings and serum cytokine pattern

The relation between gram-negative bacteremia, endotoxemia and cytokinemia in patients with hematological malignancies was studied. Serum endotoxin and cytokines (tumor necrosis factor-alpha, interleukin-1 receptor antagonist, interferon-gamma, interleukin-6 and interleukin-10) were determined in 24 patients with hematological malignancies. Patients were included at start of fever (n = 18) or during a temperature peak during continuous fever (n = 6; time = 0). Blood was drawn for cultures at time of inclusion. Additional samples were obtained and grouped in two time intervals (1-5 h and 6-12 h after inclusion). Endotoxin was detected in eight patients. Endotoxemia was more common among patients with bacteremia than among non-bacteremic patients (7/12 versus 1/12; p < 0.05). All studied cytokines showed a tendency to higher mean values at time 0 in patients with endotoxemia than in patients without endotoxemia. Significantly higher mean endotoxin values were seen at time 1-5 h in patients with gram-negative bacteremia (n = 6) than in patients without gram-negative bacteremia, and at time 0 in patients with chills (n = 6) compared to those without chills.

European Union Concerted Action on Risk Assessment in Lyme Borreliosis: clinical case definitions for Lyme borreliosis

The EU Concerted Action on Risk Assessment in Lyme Borreliosis (EUCALB) has consulted other clinicians and scientists in Europe to produce case definitions of the principal manifestations of European Lyme borreliosis. These case definitions will not only be helpful in supporting its own research interests, but are also intended to assist other clinicians in appropriate management and to support further studies aimed at determining the full clinical spectrum of the disease. The case definitions were achieved after a series of meetings organised by EUCALB with other expert clinicians and scientists from twelve European countries. The definitions and the diagnostic criteria presented thus represent the consensus reached at these meetings. The proposed case definitions consider skin, nervous system, cardiac and musculoskeletal presentations and the role of laboratory investigation in supporting diagnosis.

Diphtheria antitoxin titres six years after basic immunization of adults

Diphtheria antitoxin titres were analysed in 160 adults (median age 59 years, range 34-70), who completed basic vaccination with three doses of 7.5 Lf or 15 Lf of diphtheria toxoid (D) in a previous vaccination trial in 1987, in serum samples drawn 6 years later. The median titre had decreased from 3.2 IU ml-1 in the post vaccination samples to 0.2 IU ml-1 after 6 years in the 15 Lf group and 0.1 IU ml-1 in the 7.5 Lf group. An antitoxin titre of < 0.01 IU ml-1, a level usually considered to give no safe protection, was found in 21/73 (29%) individuals, who had received 7.5 Lf and in 12 of 87 (14%), who received 15 Lf diphtheria toxoid (P < 0.05). In the original study, the vaccinees were enrolled as unimmunized based on their own vaccination histories, but many participants had serological evidence of previous immunization. In the subgroup of 48 truly non-immune participants, i.e. without prevaccination titres and without booster response after the first injection, 46% (32% in the 15 Lf group and 58% in the 7.5 Lf group) had antitoxin levels of < 0.01 IU ml-1 6 years after basic vaccination. Therefore, individuals who have received basic vaccination with three doses of diphtheria toxoid need at least one booster injection 5-10 years later.

Enzyme-linked immunosorbent assay-based inhibition test for neutralizing antibodies to polioviruses as an alternative to the neutralization test in tissue culture

A poliovirus-binding inhibition test (PoBI test) was established for the quantitative determination of antibodies to polioviruses and was evaluated in comparison with the conventional neutralization test (NT). The first step of the PoBI test is an incubation of serial dilutions of test samples with inactivated poliovirus followed by the detection of free viral epitopes by a double antibody sandwich enzyme-linked immunosorbent assay with type-specific capture polyclonal antisera and type-specific neutralizing monoclonal indicator antibodies. A comparison of the PoBI test with the conventional NT for antibodies to all three types in 100 human serum samples showed excellent correlations (r > 0.95) over a wide range of antibody concentrations. The PoBI test, not necessitating live virus and tissue culture facilities, could be a simple alternative to the NT, and the principle of the assay is potentially applicable to other microbial systems.

Influence of high titers of maternal antibody on the serologic response of infants to diphtheria vaccination at three, five and twelve months of age

Diphtheria antitoxin was determined in serum from 44 pregnant women, of whom 26 had received one injection of diphtheria toxoid during pregnancy. Their infants were vaccinated with a combined diphtheria-tetanus vaccine at 3, 5 and 12 months of age. This vaccination schedule has been used in Sweden since 1986, replacing the old schedule of vaccination at 3, 4.5 and 6 months of age originally designed for diphtheria-tetanus-pertussis vaccine, which had not been used after cessation of general vaccination against pertussis in 1979. Serum samples from the infants were obtained at 3, 7 and 18 months of age. After 2 injections infants of mothers with high antitoxin titers, > or = 0.1 IU/ml, tended to have lower antitoxin titers than infants of mothers with low antitoxin concentrations (P = 0.067). All children had, however, antitoxin above the minimum protective level of 0.01 IU/ml. Median antitoxin titers were 1.6 IU/ml in both groups after the third booster injection. Four infants of mothers who had been vaccinated during pregnancy and who had titers of > or = 0.4 IU/ml did not reach the 0.1 IU/ml level after 2 injections: all 4 responded with high antitoxin titers after the third dose. Thus all infants were primed by 2 doses of vaccine, irrespective of maternal antibody concentration. The repressive effect of maternal antibody on titers noted after 2 doses was no longer observed after the third, booster dose.

Immunoglobulin E responses to diphtheria and tetanus toxoids after booster with aluminium-adsorbed and fluid DT-vaccines

Immunoglobulin E responses to diphtheria and tetanus toxoids were investigated in pre- and postbooster samples of 104 children given, at 10 years of age, a DT booster with either an adsorbed (n = 51) or a non-adsorbed, fluid vaccine (n = 53). Vaccination with adsorbed DT is part of a national immunisation programme and represents the first regular booster given to these children, primarily immunised with three doses of adsorbed DT at age 3-6 months. The vaccines, with a content of 30 Lf of diphtheria toxoid and 7.5 Lf of tetanus toxoid per millilitre, were given for booster in a dose of 0.25 ml as a deep subcutaneous injection. In the prebooster samples, 3 and 14% had measurable IgE to diphtheria and tetanus, respectively. These rates rose to 94 and 92% in the postbooster samples, respectively. The median (range) of IgE to tetanus among recipients of the adsorbed vaccine was 0.59 PRU ml-1 (< 0.1-17.5), as compared to 0.27 (< 0.1-8.22) in the recipients of the fluid vaccine (p = 0.027). The median IgE response to diphtheria toxoid in the whole group was 1.8 (< 0.1-17.5), with no significant difference between the two vaccines (p = 0.76). There was no correlation between the IgE and IgG responses (r < 0.07, p > 0.5) but the two IgE responses as well as the ratios of IgG/IgE showed strong correlations (r > 0.7, p < 0.001). The study thus revealed unexpectedly high rates of IgE responses to diphtheria and tetanus toxoids in a regular DT booster vaccination programme, which were associated to high rates of local side effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring of endotoxin, interleukin-6 and C-reactive protein serum concentrations in neutropenic patients with fever

Serum endotoxin, interleukin-6 (IL-6) and C-reactive protein (CRP) were serially determined in 26 patients with hematological malignancies and chemotherapy-induced neutropenia who developed fever. Endotoxin in serum was detected in 69% of the patients, with the highest values being recorded in patients with gram-negative (Gr-) bacteremia. High levels of IL-6 were found after start of fever, and in 6/9 patients with Gr- bacteremia levels exceeded 200 ng/l in samples drawn within the first 72 hours. However, only in 2/17 patients with gram-positive bacteremias and blood culture-negative fever episodes did IL-6 exceed this concentration (p < 0.05). High CRP values (exceeding 100 mg/l) did not discriminate between Gr- and non-Gr- episodes (7/9 versus 10/17, respectively). In patients with fever at day 3-5 (n = 15), IL-6 values > 100 ng/l were associated with fever continuing for more than 7 days after start of the episode; contrarily, CRP values did not indicate the persistence of fever. Determination of IL-6 may be a better test than CRP in monitoring the acute response to infection in the neutropenic patient. A combination of high endotoxin and IL-6 values may indicate a Gr- bacteremia. This could have therapeutic implications before results of blood cultures are obtained.

Micrometer- and Nanometer-Sized Polymeric Light-Emitting Diodes

A method for the fabrication of micrometer-and submicrometer-sized polymeric light-emitting diodes is presented. Such diodes have a variety of applications. Light sources of dimensions around 100 nanometers are required for subwavelength, near-field optical microscopy. Another possible application is patterning on the micrometer and nanometer scale. The diodes have been made in the form of a sandwich structure, with the conductive polymer poly(3,4-ethylene-dioxythiophene) polymerized in the pores of commercially available microfiltration membranes defining the hole-injecting contacts, poly[3-(4-octylphenyl)-2,2;-bithiophene] as the light-emitting layer, and a thin film of calcium-aluminum as the electron injector.

A comparison of four assays detecting oxidizing species. Correlated reactivity of Fe(III)-quin2, but not Fe(III)-EDTA, with hydrogen peroxide

Quin2, a fluorescent calcium probe, has a low affinity for calcium in comparison to its affinities for transition metal ions. Chelation of ferric ion with quin2 strongly enhanced the formation of oxidizing species in the presence of bolus H2O2 as detected with four assays, electron spin resonance with the spin-trap DMPO, the deoxyribose assay, the DMSO assay, and plasmid DNA strand breakage. In comparison, Fe(III)-EDTA reacted with bolus H2O2 only as detected with electron spin resonance and deoxyribose assay, but not as detected with the two latter assays. The addition of reductants, like ascorbate or superoxide generated by hypoxanthine/xanthine oxidase, to Fe(III)-EDTA in the presence of H2O2 produced plasmid DNA strand breakage and strong reactivity in both the DMSO and the deoxyribose assays. Our findings suggest that the main oxidizing species produced in Fenton-type reactions is hydroxyl radical. However, the reaction between Fe(III)-EDTA and bolus H2O2 appears to be exceptional and dominated by a nonhydroxyl radical species.

Immunoglobulin E and G responses to pertussis toxin after booster immunization in relation to atopy, local reactions and aluminium content of the vaccines

The role of aluminium for IgG and IgE responses to pertussis toxin (PT), as well as for side effects, was investigated in 49 children with known atopy status. Primary immunization had been given with an adsorbed monocomponent or an adsorbed two-component acellular pertussis vaccine. The children were then randomized to receive a booster immunization with either aluminium-adsorbed or non-adsorbed, whole cell, pertussis vaccine. Both vaccines induced good IgG responses with the adsorbed vaccine giving higher post-booster levels (p < 0.05). The adsorbed vaccine was, however, associated with more local side effects (p < 0.05) and tended to induce higher PT-IgE responses than the non-adsorbed vaccine. Furthermore, individuals who had received the two-component vaccine as primary immunization had higher PT-IgE responses after the booster, compared with individuals initially receiving the monocomponent vaccine (p = 0.041). No correlation between PT-IgE and PT-IgG levels was seen in any of the groups. Total serum IgE levels correlated to PT IgE levels, particularly in children with atopy (r = 0.950, p < 0.001). The addition of aluminium to the pertussis vaccine, was, thus, associated with a stronger IgG antibody response, but tended also to induce a stronger IgE antibody response. The correlation between total IgE and PT-IgE, which was most prominent in children with atopy, indicates that the role of immunization for the development of allergy merits further studies.

The role of IgA determination by ELISA in the early serodiagnosis of Mycoplasma pneumoniae infection, in relation to IgG and mu-capture IgM methods

Enzyme-linked immunosorbent assay (ELISA) for IgA, IgG and IgM was evaluated with sera from 50 adult patients with pneumonia, selected on the basis of a positive complement fixation (CF) test for diagnosis of Mycoplasma pneumoniae infection and with sera from 105 healthy blood donors. The ELISA antigen for IgG and IgA was a sonicated suspension of M. pneumoniae solubilised by deoxycholate. For the IgM assay, the same antigen was directly conjugated to alkaline phosphatase and used in a mu-capture format. ELISA gave positive results with high or rising titres for one or several antibody classes in 47 (94%) patients. In two of the three ELISA-negative cases, the diagnosis of M. pneumoniae infection indicated by the CF test seemed unlikely on clinical grounds. Specific IgA antibodies was developed more regularly and more rapidly than IgM. IgA titres also started to decrease earlier than IgM or the late-peaking IgG response. Thus, the determination of IgA antibodies was found to be valuable for the early diagnosis of M. pneumoniae infection. The study also demonstrated that the determination of all three antibody classes is necessary to obtain an optimal level of serodiagnosis.