Biomedical subjects
J Forster
Publications and source records attributed to J Forster.
Attacking managed care with a full-court press.
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What are you really good at?
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The Ile198Thr and Ala379Val variants of plasmatic PAF-acetylhydrolase impair catalytical activities and are associated with atopy and asthma.
The platelet-activating factor (PAF) represents a phospholipid with complex biological functions, including involvement in inflammatory processes. The degrading enzyme PAF acetylhydrolase (PAFAH) represents a candidate for asthma and other atopic diseases. Two loss-of-function mutations of PAFAH are associated with severe asthma in Japanese individuals. Our aim was to look for further PAFAH variants in white populations, their possible association with atopic and asthmatic phenotypes, and their functional importance. We picked up three common variants in the PAFAH gene: Arg92His (exon 4), Ile198Thr (exon 7), and Ala379Val (exon 11). The known loss-of-function mutations were not seen. The variant allele Thr198 was found to be highly associated with total IgE concentrations in an atopic population (P=.009) and with "atopic asthma" in an asthmatic population (P=.008). The variant allele Val379 was found to be highly associated with "specific sensitization" in the atopic population (P=.002) and with "asthma" in the asthmatic population (P=.003). By use of recombinant PAFAH enzymes, the variant Val379 showed increased (14 microM) and Thr198 markedly increased (42 microM) KM values compared to the wild type (7 microM); furthermore, Vmax of Val379 was highly increased (132%). Thr198 and Val379 influence plasmatic PAFAH toward lower substrate affinities and therefore are very likely to prolong the activities of PAF. At the same time, they are associated with an increased risk to develop asthma and atopy. Thus, two PAFAH variants seem to play a key role in atopic and asthmatic processes in Caucasian populations.
Now what? 7 tasks for a new beginning.
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Your own five-year plan: what do you want to accomplish?
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[Prospective study of JCR-Oligo I of the Child and Adolescence Rheumatology Working Group].
Intra-articular injection of corticosteroids is a powerful anti-inflammatory treatment with relatively few side effects. To date no prospective RCT exists on its use in children with oligoarthritis type I. Thus, in January 2000 the Arbeitsgemeinschaft started a multicenter RCT to compare in children with this diagnosis the initial treatment recommended in the textbooks, which is NSAID plus physiotherapy, with the early use of intra-articular injection of Triamcinolonhexacetonide. In the synovial fluid the presence of cytokines and the specific reactivity of T cells will be explored, and a highly sensitive screening for infectious agents will be performed.
[Recommendations by the Pediatric and Adolescent Rheumatology Study Committee on therapy with Etanercept (p75 TNF-alpha receptor immunoglobulin fusion protein. Pharmacotherapy Committee].
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Elevated gene expression of interleukin-8 in cord blood is a sensitive marker for neonatal infection.
Bacterial infection is a major cause of neonatal morbidity and mortality. Early diagnosis is essential for a successful treatment and outcome. Cytokine plasma levels are suggested to be sensitive parameters for the diagnosis of neonatal sepsis. The aim of this study was to assess cytokine mRNA expression in cord blood cells as a marker for neonatal infection. In a prospective study, cord blood samples of neonates with septic bacterial infection were analyzed qualitatively and semiquantitatively by reverse transcriptase-polymerase chain reaction (RT-PCR) for mRNA expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, as well as for IL-8 cord plasma levels. Results were compared to those of non-septic neonates. A method was used requiring only a microvolume (25 microl or less) of cord blood. Cord plasma levels of IL-8 were significantly elevated in septic infants (n = 9) when compared to infants with not confirmed sepsis (n = 22) and healthy infants that served as controls (n = 68) (median 1,686 vs 262.7 vs 33.1 pg/ml, P < 0.001). The presence of IL-6 and TNF-alpha gene expression was observed more frequently in septic than in non-septic patients; sensitivity, however, reached only 56 and 67%, respectively. When using a semiquantitative approach for analyzing IL-8 mRNA levels, a high sensitivity (86%) and specificity (96%) for the detection of sepsis was achieved. A new method for the early diagnosis of neonatal infection is described measuring cytokine mRNA in neonatal cord blood cells. With this molecular approach only a microvolume of blood is required for analysis.
Eosinophil cationic protein and eosinophil protein X in the nasal lavage of children during the first 4 weeks of life. SPACE Collaborative Study Team.
Eosinophil cationic protein (ECP) and eosinophil protein X (EPX) are well established as markers of eosinophil activation. We analyzed ECP and EPX concentrations in nasal lavage fluids (NALF) of 378 neonates during their first 4 weeks of life. Inclusion criteria were a positive history of parental allergy and a positive skin prick test or specific IgE (RAST class > or = 2) against at least one out of a panel of common aeroallergens in one or both parents. Twenty-four infants with no history of parental allergy were used as controls. A volume of 2 ml of 0.9% saline was instilled into each nostril and immediately recovered by a suction device. ECP and EPX were analyzed by radioimmunoassay. In 65 samples of three consecutive lavages, EPX was detected in nine samples (13.8%) in the control group, whereas it was detected in 197/360 samples (54.7%) in the study population. The corresponding figures for ECP were 17/65 (26.2%) in the control group and 173/365 (47.4%) in the study group. Both proteins showed a skewed distribution (median/5-95th percentiles for ECP: 0 microg/l [0-69.4] and EPX: 6.6 microg/l [0-73.2]). The differences between the control group and the study group were statistically significant, regardless of the allergic disease of the parents. In children of allergic parents, activation proteins of the eosinophil granulocyte are released on the nasal mucosal surface in about 50% of the studied population at the age of 4 weeks. This early onset of eosinophil activation in the nasal respiratory epithelium may reflect a genetic predisposition to allergy or early exposure to allergens.
Studies on linkage and association of atopy with the chromosomal region 12q13-24.
BACKGROUND: Several studies have shown linkage of bronchial asthma, allergic rhinitis and total serum IgE concentration to the chromosomal region 12q13-24 in ethnical diverse populations. This region harbours a number of candidate genes for asthma and atopy, including stem cell factor (SCF), leukotriene A4 hydrolase (LTA4H), thyroid receptor 2 (TR2), and signal transducer and activator of transcription 6 (STAT6). However, the same region was shown as well to be linked to other diseases with inflammatory character. So far no variants in any of these genes have been published which would allow association studies and confirm the pathogenicity of any of these genes. OBJECTIVE: We wanted to test for linkage of the chromosomal region 12q13-24 with the atopic phenotype without regard to clinical manifestations. Furthermore we screened for common nucleotide polymorphisms in candidate genes to enable association studies. METHODS: We employed sib-pair linkage analysis and transmission disequilibrium testing with regard to four highly polymorphic microsatellite markers in 12q13-24 in atopic nuclear families. In addition, we looked for polymorphisms in the genes coding for SCF, LTA4H, TR2 and STAT6 performing SSCP-analysis and direct genomic sequencing. RESULTS: We found no evidence for linkage of the genomic region 12q13-24 to elevated total serum IgE levels, specific sensitization to common inhalant allergens or atopy. Furthermore we identified three nucleotide polymorphisms including one common variant in the gene coding for SCF. No association of this polymorphism and any of the atopic phenotypes was seen. CONCLUSION: We conclude from our data that genes in the chromosomal region 12q13-24 and in particular SCF are unlikely to exert a major effect on the induction of the atopic phenotype in our Caucasian population. However, we did not focus on the asthmatic and thereby inflammatory aspect of atopy which might explain these results in contradiction to previous studies.
Common polymorphisms in the CTLA-4 and CD28 genes at 2q33 are not associated with asthma or atopy.
Recently, genetic linkage of the chromosomal region 2q33 with asthma has been shown. The genes coding for CD28 and CTLA-4 have been localized to this chromosomal region. CD28 and CTLA-4 have been shown to be involved as an important costimulatory signal in the regulation of allergic inflammation and TH2 cytokine production, and thus both genes are good candidate genes for asthma and atopy. Two common polymorphisms in the CTLA-4 gene and one polymorphism in the CD28 gene found by single-strand conformation polymorphisms (SSCP) analysis and direct genomic sequencing were tested for association with asthma and atopy phenotypes in a population of 260 largely atopic children and young adults. No association was found between any of the three polymorphisms and asthma or atopy phenotypes. The newly described common CD28 polymorphism is situated in the third intron of the gene. We conclude that neither gene is likely to exert a major influence on the development of asthma or atopy in our population. However, it might prove useful to test for association of these polymorphisms with asthma in populations recruited through asthmatic but not necessarily atopic individuals.
Common polymorphisms and alternative splicing in the ILT3 gene are not associated with atopy.
Recently, a linkage of the chromosomal region 19q13.4 with bronchial asthma has been demonstrated. This region harbours the so-called leucocyte receptor cluster with the gene for immunoglobulin-like-transcript 3 (ILT3) as a member. ILT3 represents an inhibitory receptor bearing three immunoreceptor tyrosine inhibitory motifs (ITIM). The protein mediates downregulation of cell activation through recruitment of different SH2-containing protein tyrosine phosphatases. With regard to the negative immunoregulatory function particularly on B-cells, ILT3 represents a candidate gene for atopy and asthma. The aim of this study was to screen for common polymorphisms in the gene coding for ILT3 and to test for association with the atopic phenotype. Using single-stranded conformal polymorphism-analysis and direct genomic sequencing seven polymorphisms, three mutations, a common deletion of 7 bp in the third intron and evidence for further alternative splicing of the ILT3 gene were found. Although no association was found with atopy phenotypes, it might prove useful to test for association with bronchial asthma.
Increased left ventricular mass index and nocturnal systolic blood pressure in patients with Type 2 diabetes mellitus and microalbuminuria.
AIMS: To compare left ventricular mass (LVM) index and function in patients with Type 2 diabetes mellitus with and without microalbuminuria and to investigate the clinical determinants of left ventricular hypertrophy. METHODS: Echocardiography, electrocardiography and 24-h ambulatory blood pressure monitoring were performed in microalbuminuric (n = 29) and normoalbuminuric (n = 29) patients with Type 2 diabetes and no clinical evidence of heart disease. Groups were individually matched for age, sex and diabetes duration and smoking status. RESULTS: LVM index (62 (34-87) vs. 52 (33-89) g/m2.7, P = 0.04) and LVH prevalence, using two out of three definitions, were greater in patients with microalbuminuria (LVM/height2.7: 72 vs. 59%, P = 0.27, LVM/height: 66 vs. 38%, P = 0.04, LVM/body surface area: 59 vs. 31%, P = 0.03). Night-time systolic blood pressure (126 (99-163) vs. 120 (104-157) mmHg, P = 0.005) and the night/day systolic blood pressure ratio (0.92 (0.08) vs. 0.88 (0.06), P = 0.04) were higher in those with microalbuminuria. Systolic and diastolic function were similar in both groups. Linear regression analyses showed that body mass index (BMI) was significantly related to loge LVM index (R2 = 11.8%, P = 0.005) and a relationship with night/day systolic blood pressure was also suggested (R2 = 4.6%, P = 0.057). CONCLUSIONS: In patients with Type 2 diabetes, LVH is more common and severe in those with microalbuminuria. Its presence may be related to raised night/day systolic blood pressure ratio and is significantly related to BMI. The high prevalence of LVH strengthens the case for echocardiographic screening in Type 2 diabetes to identify high risk patients who might benefit from aggressive cardiovascular risk factor intervention.
Association and linkage of atopic dermatitis with chromosome 13q12-14 and 5q31-33 markers.
Atopic dermatitis is a chronic inflammatory skin disease that affects 10-20% of the population. Linkage of atopy, asthma, allergic rhinitis, and total serum IgE levels to several different chromosomal regions have been described extensively, but little is known about the genetic control of atopic dermatitis. We tested for the association and linkage between atopic dermatitis and five chromosomal regions: 5q31-33, 6p21.3, 12q15-24.1, 13q12-31, and 14q11.2/14q32.1-32.3. Marker analysis was performed in two Caucasian populations: (i) 192 unrelated German children with atopic dermatitis and 59 non-atopic children from a German birth cohort study (MAS'90), parental DNA was tested in 77 of 192 children with atopic dermatitis; (ii) 40 Swedish families with at least one family member with atopic dermatitis selected from the International Study of Asthma and Allergy in Children. Evidence for linkage and allelic association for atopic dermatitis was observed for markers on chromosome 13q12-14 and 5q31-33.
Development of seasonal allergic rhinitis during the first 7 years of life.
BACKGROUND: Against the background of the controversial discussion about an increase in allergic rhinitis in recent years, intraindividual longitudinal data is lacking for IgE-mediated seasonal allergic rhinitis (SAR). Little is known about the development of SAR in terms of prevalence and incidence rates from birth to school age. OBJECTIVE: In a prospective birth cohort, we investigated the development of sensitization and symptoms of SAR. SAR should be defined with high specificity, and associated risk factors should be determined. METHODS: Annual longitudinal data about seasonal allergic symptoms and sensitization was available for 587 children from birth to their seventh birthday. The definition of SAR was based on a combination of exposure-related symptoms and sensitization. RESULTS: Up to 7 years of age, SAR developed in 15% of the children. Incidence and prevalence of symptoms and sensitization were low during early childhood (<2%) and increased steadily with age. Children in which SAR had already developed in the second year all were born in spring or early summer, resulting in at least two seasons of pollen exposure before manifestation of SAR. Risk factors assessed by multiple logistic regression analysis were male sex (odds ratio [OR] = 2.4), atopic mothers (OR = 2.6) and fathers (OR = 3.6) having allergic rhinitis themselves, first-born child (OR = 2.0), early sensitization to food (OR = 3.3), and atopic dermatitis (OR = 2.5), whereas early wheezing was not associated with SAR. CONCLUSION: The development of SAR is characterized by a marked increase in prevalence and incidence after the second year of life. Our longitudinal data further indicate that in combination with the risk of allergic predisposition, at least 2 seasons of pollen allergen exposure are needed before allergic rhinitis becomes clinically manifest.
A European study on the genetics of mite sensitization.
BACKGROUND: Sensitization to mite allergens represents a prominent feature of atopy and an important predictor of bronchial asthma. OBJECTIVE: It was the intention of this study to define genetic loci linked to mite sensitization because these could represent the genetic basis of the important atopic component of asthma. METHODS: We studied a multiethnic white population of 99 families, including 224 sib pairs sensitized to Dermatophagoides pteronyssinus. A genome-wide candidate-region search was performed that covered potential asthma and atopy regions. RESULTS: As for nonparametric linkage (NPL) analysis, 14 of the candidate regions showed evidence for linkage (NPL > 2.0), and 4 of them showed prominent linkage (NPL > 3.0). However, there were substantial ethnic differences. Maximizing the LOD score analysis identified candidate regions with suspected dominant and recessive mode of inheritance. Furthermore, genetic imprinting models provided significant evidence for linkage in the 8p23 region and revealed potential maternal imprinting. The regions found are distinct to those in asthma searches that have been found to be linked to asthma, as well to other inflammatory diseases. In addition, we could not find linkage to the HLA region. By different cutoff points of the phenotype definition, the IL cluster showed evidence of being linked to the degree of sensitization rather than to sensitization per se. CONCLUSION: The results indicate that the genetic basis of the atopic component of asthma is different from that of the inflammatory component. Furthermore, it seems reasonable to assume that specific sensitizations are influenced by distinct genetic variants leading to their initiation versus those leading to their enhancement.