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Biomedical subjects

J Forster

Publications and source records attributed to J Forster.

At least 109 records · Page 6Linked to original sources

Specific IgE and IgG4 immune responses to tetanus and diphtheria toxoid in atopic and nonatopic children during the first two years of life.

BACKGROUND: In order to investigate, whether atopic and nonatopic children show differences in their specific IgE and IgG4 immune responses to tetanus (T) and diphtheria (D) antigens, we studied 538 children who had been followed from birth on and from whom records had been kept of all immunizations. METHODS: The prevalence of eczema and asthma was registered at regular intervals and the cumulative incidence of symptoms was determined at 24 months of age. Total serum IgE and specific IgE to a panel of nine allergens as well as T- and D-specific IgE and IgG4 were determined from the 24-months blood samples. RESULTS: Our results show that both atopic and nonatopic children are capable of mounting high levels of toxoid-specific IgE antibody responses. Children with cord blood IgE > 0.9 kU/1, serum IgE 10-100 kU/1 and > 100 kU/1 and at least one sensitization to an allergen at 24 months of age have significantly higher IgE responses to T and D (p < 0.001). In contrast, specific IgG4 antibody concentrations to T and D were not significantly different in children with elevated total IgE levels at 24 months. No differences in subgroups of children with or without early symptoms of atopy were observed. CONCLUSIONS: Our data indicate that IgE responses to toxoids such as T and D are not limited to infants with clinical manifestations of atopy in the first 2 years of life but are related to immunological parameters of atopy.

Asthma↗

Detection of HLA IgG antibodies by two enzyme-linked immunoassays, solubilized HLA class I and PRA-STAT. Comparison with the AHG PRA.

HLA class I-directed IgG antibodies have traditionally been detected with a complement-dependent lymphocytotoxicity (CDL) technique. We have evaluated two solid-phase enzyme-linked immunoassays (EIA) and compared them with the CDL antihuman globulin (AHG) dithiothreitol-treated (DTT) PRA in their ability to discriminate between the presence or absence of HLA class I-directed IgG antibodies in serum from patients awaiting transplantation. The EIA were: (1) an EIA that uses solubilized HLA class I antigens (sHLA-I) isolated from a 240-member platelet donor pool, and (2) the PRA-STAT ELISA kit. For the first comparison, we used 691 serum samples from 272 patients taken before they had been transplanted. The data show a significant (P < 0.0001) linear correlation (r = 0.77 between the AHG DTT PRA and the sHLA EIA. They also demonstrate that the mean sHLA-I EIA ratio significantly increases (P < 0.01) above background levels with each stepwise increase in AHG DTT PRA level. Discordant results were 1.0% (7/691) for sHLA-I EIA+ PRA- and 6.3% (44/691) for PRA+ sHLA-I EIA-. However, a lower correlation was noted between the AHG DTT PRA and the PRA-STAT (Nextran) PRA results (n = 230; r = 0.42). The sHLA-I EIA is able to determine whether or not HLA Class I IgG antibodies are present in serum from transplant candidates and is an appropriate adjunct to the traditional CDL PRA assay, whereas the PRA-STAT is not.

Enzyme-Linked Immunosorbent Assay↗

Liver transplantation in a patient with sickle cell anemia.

Orthotopic liver transplantation in a patient with sickle cell disease presents many new challenges to the transplant team. We describe the case of a 47-year-old patient with sickle cell disease and hepatitis C virus-induced cirrhosis who required liver transplantation.

Anemia, Sickle Cell↗

Magnetization transfer in hemopoietic bone marrow examined by localized proton spectroscopy.

The sensitivity of hemopoietic bone marrow to magnetization transfer is analyzed in 15 healthy volunteers and seven patients with different hematological disorders (inflammation, plasmacytoma, hemopoietic reconstitution after bone marrow transplantation). To obtain sufficient signal-to-noise ratio, a 90 degrees - 180 degrees - 180 degrees double spin echo (PRESS) single voxel spectroscopic method was combined with pulsed magnetization transfer. Several spectra were recorded from each volume element inside the vertebral marrow, alternately with and without prepulses for magnetization transfer. Water signals from marrow with increased content of extracellular water due to inflammation or edema revealed less magnetization transfer effects than marrow with increased intracellular water content due to high cellularity. The preliminary results show magnetization transfer to be a promising tool for the clinically important characterization of the water composition in red bone marrow.

Adult↗

Magnetization transfer by simple sequences of rectangular pulses.

On-resonant radio frequency (RF) sequences composed of a train of short rectangular pulses of the same kind were optimized in order to obtain selective saturation of protons with short transverse relaxation times for magnetization transfer purposes. It is demonstrated that the sequences regarded allow a good adaptation to different requirements for magnetization transfer examinations on whole-body imagers. The sequences presented here provide relatively strong saturation of protons with very short transverse relaxation times T2 approximately less than 50 microseconds, whereas signals from protons with long T2 to be recorded are hardly influenced in a broad frequency range. The sequences are especially advantageous for applications in pulse files with limited numbers of support points.

Magnetic Resonance Imaging↗

Characterization of antigens and allergens in hypo-allergenic infant formulae.

The antigenicity and allergenicity of so-called hypo-allergenic infant formulae is mainly determined by the degree of hydrolysis and ultrafiltration. Five different formulae were investigated by means of immunoblotting and RAST in order to characterize the antigens and allergens regarding their molecular weights, molecular origin and their ability to bind human IgG and IgE antibodies: A non hydrolysed infant formula (I-F), a mixture of the major cow's milk proteins (PM), a whey-based infant formula (W-H), a whey-based and ultra-filtrated infant formula (U-H), a casein/whey-based infant formula (CW-H). By immunoblotting we demonstrated that all tested formulae still contain antigens with molecular weights from 3 to 67 kD. But when compared with I-F and PM the antigen content of the hydrolysed formulae was considerably lower. The lowest antigen content could be demonstrated in U-H, which contains casein fragments (3-6 kD) and beta-lactoglobulin and its fragments (6-18 kD). W-H and CW-H contain bovine serum albumin, beta-lactoglobulin, casein and their fragments (3-67 kD). All hydrolysed formulae tested showed a reduced IgE-binding capacity. Three out of 12 cow's milk allergic children possessed IgE binding to U-H or W-H, and 5 of them IgE against CW-H. Conclusion. The enzymatic hydrolysis plus ultra-filtration seems to be the most efficient method to reduce the antigen content of so-called hypo-allergenic infant formulae.

Allergens↗

The clinical picture presented by premature neonates infected with the respiratory syncytial virus.

During the course of a 3-year epidemic of respiratory syncytial virus (RSV) in an Neonatal Intensive Care Unit, we examined premature neonates for the clinical features of RSV infections and the risk factors predisposing towards transmission of the disease. Seventy-nine infants with a median gestational age of 31 weeks were tested in 113 episodes of clinical deterioration for the presence of RSV antigen in nasopharyngeal secretions. Forty-seven results were positive and 66 negative. Bradycardia, which is gestational-age dependent, was the main presenting clinical symptom of an RSV infection in 75% of cases. The probability of an RSV-positive result in an episode with bradycardia, hypercapnia and fever was calculated to be 0.75. The only identifiable epidemiological risk factor was the total number of symptomatic RSV-infected infants in the ward. CONCLUSION. Bradycardia may indicate the presence of an RSV infection: the appropriate tests should be carried out and infection control reinforced immediately.

Antigens, Viral↗

Subsequent insect stings in children with hypersensitivity to Hymenoptera.

To investigate the risk of life-threatening reactions to future stings, we sequentially challenged 113 children (aged 2 to 17 years) allergic to insect stings with a sting by the relevant insect. The time interval between the challenges varied from 2 to 6 weeks. The history of the index stings was a large local reaction (LR) in 16% and a systemic reaction (SR) in 84% of the test subjects. On the first challenge, 76% had a normal LR, 11% a large LR, and 13% an SR. On the second challenge, 78% of the children had a normal LR, 5% a large LR, and 17% an SR. Thirty-nine of the untreated children were exposed to a field sting during the subsequent 3-year follow-up period. In comparison with other diagnostic evaluations such as skin-prick tests, determinations of specific IgE and IgG antibodies, and single-sting exposure, the dual sting challenge scheme appears to be the best predictor of reactions to subsequent stings. It also appears to be helpful in selecting patients with an uncertain sensitization status for venom immunotherapy.

Adolescent↗

Sensitization to mite allergens is a risk factor for early and late onset of asthma and for persistence of asthmatic signs in children.

BACKGROUND: To describe the natural history of asthma between the ages of 7 and 10 years and to analyze risk factors for prevalences, as well as new onset of asthma-like symptoms, a longitudinal study of 1812 children was conducted. METHODS: In four surveys, each 1 year apart, four asthma-like symptoms and several hypothetical risk factors were ascertained through standardized questionnaires. Sensitization to seven common inhalant allergens was measured by skin prick testing. Exposure to mite allergens (Der p I, Der f I) was assessed by measuring the antigen concentrations in the dust of each child's mattress. Occurrence of more than one asthma-like symptom closely related to the practioner's diagnoses of bronchial asthma and recurrent wheezy bronchitis was used as the outcome variable. RESULTS: After an initial prevalence of 14.5%, new onset of symptoms in children unaffected at the beginning was reported in 7.2% during the 3 years. Of the factors explaining prevalence and persistence of asthma-like symptoms (sensitization to mite allergens and animal danders, history of hay fever and eczema, low gestational age, male gender, parental atopy), only sensitization to mite allergens (odds ratio = 2.3, 95% confidence interval = 1.1-4.7) and parental atopy (odds ratio = 2.1, 95% confidence interval = 1.2-3.7) were also significantly associated with new onset. In a relatively small number of sensitized subjects with new onset of symptoms (n = 31), mite antigen concentration did not appear to be associated with incidence of symptoms. CONCLUSION: Sensitization to mite allergens antedated the onset of asthma-like symptoms, and no strong effect of allergen exposure on clinical development could be found. Thus the primary focus should be on preventing sensitization to mite allergens by implementing avoidance measures in infancy or at early school age in order to reduce the onset of asthma at a later stage.

Allergens↗

Settings as an important dimension in health education/promotion policy, programs, and research.

Settings--community, worksite, schools, and healthcare sites--constitute an important dimension of health education/health promotion policy and programs and for research about program needs, feasibility, efficacy, and effectiveness. These settings vary in the extent of coverage of and relationships with their respective constituencies, valued outcomes, and quantity and quality of evidence about the effectiveness of setting-specific and cross-setting programs. Main sources of evidence for program efficacy and effectiveness are summarized, leading to the conclusion that strides have been made toward building a strong evidentiary base for health education/health promotion in these settings. Gaps in research exist, especially for diffusion of effective programs, new technologies, the influence of policy, relations between settings, and approaches to marginal and special subgroups. Recommendations are offered for cross-setting and within-setting research related to intervention.

Community Health Services↗

Creating capacity: establishing a health education research agenda for special populations.

On Day 2 of the joint CDC/SOPHE conference on Creating Capacity: Establishing a Research Agenda for Health Education, the participants were asked to identify research needs or special issues in working with children and adolescents, the elderly, women, men, and underserved groups. This article presents the priority research areas across subgroups identified by the participants. The cross-group priorities are followed by research recommendations for each subgroup.

Adolescent↗

Anaphylactic reactions to bee-sting challenges in allergic children are not modified by endogenous catecholamines.

To investigate the role of basal catecholamine levels and the response of the adrenergic system to expected bee stings, plasma catecholamines were measured before and 1 and 2 min after bee-sting challenges. Twenty-one children (aged 4-15 y) with bee-sting allergies were selected for sequential challenges to establish the need for venom immunotherapy. The time interval between the challenges varied from 2 to 6 wk. Epinephrine, norepinephrine, and dopamine plasma levels were measured using a simultaneous single-isotope radioenzymatic assay. On the first challenge, 33% of the children experienced a normal local reaction, 29% a large local reaction, and 38% a systemic reaction. On the second challenge in 18 out of 21 subjects, 67% experienced a normal normal local reaction, 22% a large local reaction, and 11% a systemic reaction. Epinephrine and norepinephrine plasma levels increased significantly on the first and second challenges. Dopamine plasma levels showed a significant increase on the first challenge only. Plasma catecholamine levels after the second challenge revealed a significant positive correlation between epinephrine increases measured 1 and 2 min after the challenge and the concomitant sting reaction. Basal epinephrine, norepinephrine, and dopamine plasma levels did not differ significantly between patients who experienced different types of sting reactions. Based on our data, we conclude that clinical reactions to in-hospital insect-sting challenges are not affected by early increases in plasma catecholamine levels produced by the expected stress situation.

Adolescent↗

[Food allergy].

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Child↗