FLT3 ligand and not TSLP is the key regulator of IL-7-independent B-1 and B-2 B lymphopoiesis

Phenotypically and functionally distinct progenitors and developmental pathways have been proposed to exist for fetally derived B-1 and conventional B-2 cells. Although IL-7 appears to be the primary cytokine regulator of fetal and adult B lymphopoiesis in mice, considerable fetal B lymphopoiesis and postnatal B cells are sustained in the absence of IL-7; in humans, B-cell generation is suggested to be largely IL-7-independent, as severe combined immune-deficient patients with IL-7 deficiency appear to have normal B-cell numbers. However, the role of other cytokines in IL-7-independent B lymphopoiesis remains to be established. Although thymic stromal lymphopoietin (TSLP) has been proposed to be the main factor driving IL-7-independent B lymphopoiesis and to distinguish fetal from adult B-cell progenitor development in mice, recent studies failed to support a primary role of TSLP in IL-7-independent fetal B-cell development. However, the role of TSLP in IL-7-independent adult B lymphopoiesis and in particular in regulation of B-1 cells remains to be established. Here we demonstrate that, rather than TSLP, IL-7 and FLT3 ligand are combined responsible for all B-cell generation in mice, including recently identified B-1-specified cell progenitors. Thus, the same IL-7- and FLT3 ligand-mediated signal-ing regulates alternative pathways of fetal and adult B-1 and B-2 lymphopoiesis.     

RecA tests homology at both pairing and strand exchange

RecA is a 38-kDa protein from Escherichia coli that polymerizes on single-stranded DNA, forming a nucleoprotein filament that pairs with homologous duplex DNA and carries out strand exchange in vitro. To observe the effects of mismatches on the kinetics of the RecA-catalyzed recombination reaction, we used assays based upon fluorescence energy transfer that can differentiate between the pairing and strand displacement phases. Oligonucleotide sequences that produced 2–14% mismatches in the heteroduplex product of strand exchange were tested, as well as completely homologous and heterologous sequences. The equilibrium constant for pairing decreased as the number of mismatches increased, which appeared to result from both a decrease in the rate of formation and an increase in the rate of dissociation of the intermediates. In addition, the rate of strand displacement decreased with increasing numbers of mismatches, roughly in proportion to the number of mismatches. The equilibrium constant for pairing and the rate constant for strand displacement both decreased 6-fold as the heterology increased to 14%. These results suggest that discrimination of homology from heterology occurs during both pairing and strand exchange.     

Heterozygosity of CDAN II (HEMPAS) gene may be detected by the analysis of erythrocyte membrane glycoconjugates from healthy carriers

BACKGROUND AND OBJECTIVES: Congenital dyserythropoietic anemia (CDA) type I, II, and III, is associated with abnormalities of erythrocyte membrane glycoconjugates that are most pronounced in type II CDA or hereditary erythroblastic multinuclearity with a positive acidified-serum test (HEMPAS). The abnormalities consist in hypoglycosylation of polylactoaminoglycans linked to proteins (as in band 3 glycoprotein) and ceramides (known under the name of polyglycosylceramides) as well as in accumulation of some oligoglycosylceramides: lactotriaosylceramide, neolactotetraosylceramide, and sometimes globotetraosylceramide. Glycophorin A is partially unglycosylated with respect to O-linked glycans. Types I and II of the disease are inherited in an autosomal recessive fashion. The aim of the present study was to investigate a possibility that heterozygosity with respect to CDAN2 gene in healthy carriers could be detected by analysis of erythrocyte membrane glycoconjugates. DESIGN AND METHODS: We examined a family which consisted of heterozygous parents and their two sons, one of whom was afflicted with CDA II (proband) while the other was healthy. In all family members the glycosylation status of band 3 glycoprotein, polyglycosylceramides and glycophorin A was evaluated from their carbohydrate molar composition. In addition we determined erythrocyte membrane contents of oligo- and polyglycosylceramides, and agglutinability of erythrocytes by anti-i antibody. RESULTS: We found that the heterozygous parents showed, but about 50% less pronounced, most of the typical abnormalities of erythrocyte membrane glycoconjugates that were present in the proband. These abnormalities included: hypoglycosylation of band 3, accumulation and hypoglycosylation of polyglycosylceramides, and accumulation of lactotriaosylceramide. The level of neolactotetraosylceramide in the erythrocyte membranes of the parents was, however, normal. Globotetraosylceramide content was elevated in erythrocytes from the proband and, surprisingly, even more so in the parents. Glycophorin A in the proband was only slightly abnormal. Erythrocytes from both the parents and the proband expressed increased agglutinability with anti-i antibody. All glycoconjugates examined were normal in erythrocytes from the healthy son. INTERPRETATION AND CONCLUSIONS: Individuals heterozygous with respect to CDAN2 gene can be identified through determination of the carbohydrate molar composition of band 3 and polyglycosylceramides as well as by an elevated erythrocyte content of polyglycosylceramides. In the parents these abnormalities show dosage effects. Determination of the carbohydrate molar composition of glycophorin A and of oligoglycosylceramides seems to be less promising. These findings indicate that the analysis of erythrocyte membrane glycoconjugates may be a valuable addition to the repertoire of methods used in studies on the genetics of CDA.     

Occupational allergic and irritant contact dermatitis in workers exposed to polyurethane foam

Objectives

To evaluate sensitization to chemicals present in work environment after an outbreak of contact dermatitis in workers of vehicle equipment factory, exposed to polyurethane foam, based on 4,4′-diphenylmethane diisocyanate (MDI).

Material and Methods

From among 300 employees, 21 individuals reporting work-related skin and/or respiratory tract symptoms underwent clinical examination, patch testing, skin prick tests, spirometry and MDI sIgE measurement in serum. Patch tests included isocyanates series, selected rubber additives, metals, fragrances, preservatives, and an antiadhesive agent.

Results

Clinical examination revealed current eczema in the area of hands and/or forearms in 10 workers. Positive patch test reactions were found in 10 individuals, the most frequent to diaminodiphenylmethane and 4-phenylenediamine (7 persons). Reactions to an antiadhesive agent were assessed as irritant (5 workers). Except for sensitization to common aeroallergens, no significant abnormalities were found in the remaining tests. Occupational allergic contact dermatitis was diagnosed in 7 workers, irritant contact dermatitis in 10 and coexisiting allergic and irritant contact dermatitis in 3 workers.

Conclusions

In workers manufacturing products from polyurethane foam, attention should be paid to the risk of developing contact dermatitis. Skin problems in our study group were attributable probably to insufficient protection of the skin.     

Polymorphisms in TS,MTHFR and ERCC1 genes as predictive markers in first-line platinum and pemetrexed therapy in NSCLC patients

Purpose

We presented retrospective analysis of up to five polymorphisms in TS, MTHFR and ERCC1 genes as molecular predictive markers for homogeneous Caucasian, non-squamous NSCLC patients treated with pemetrexed and platinum front-line chemotherapy.

Methods

The following polymorphisms in DNA isolated from 115 patients were analyzed: various number of 28-bp tandem repeats in 5′-UTR region of TS gene, single nucleotide polymorphism (SNP) within the second tandem repeat of TS gene (G>C); 6-bp deletion in 3′-UTR region of the TS (1494del6); 677C>T SNP in MTHFR; 19007C>T SNP in ERCC1. Molecular examinations’ results were correlated with disease control rate, progression-free survival (PFS) and overall survival.

Results

Polymorphic tandem repeat sequence (2R, 3R) in the enhancer region of TS gene and G>C SNP within the second repeat of 3R allele seem to be important for the effectiveness of platinum and pemetrexed in first-line chemotherapy. The insignificant shortening of PFS in 3R/3R homozygotes as compared to 2R/2R and 2R/3R genotypes were observed, while it was significantly shorter in patients carrying synchronous 3R allele and G nucleotide. The combined analysis of TS VNTR and MTHFR 677C>T SNP revealed shortening of PFS in synchronous carriers of 3R allele in TS and two C alleles in MTHFR. The strongest factors increased the risk of progression were poor PS, weight loss, anemia and synchronous presence of 3R allele and G nucleotide in the second repeat of 3R allele in TS. Moreover, lack of application of second-line chemotherapy, weight loss and poor performance status and above-mentioned genotype of TS gene increased risk of early mortality.

Conclusion

The examined polymorphisms should be accounted as molecular predictor factors for pemetrexed- and platinum-based front-line chemotherapy in non-squamous NSCLC patients.     

Mitochondrial genome variation in male LHON patients with the m.11778G > A mutation

Metabolic Brain Disease - Leber hereditary optic neuropathy (LHON) is a mitochondrial disorder with symptoms limited to a single tissue, optic nerve, resulting in vision loss. In the majority of...     

Clinical signs in the jaw and neck region following whiplash trauma—A 2-year follow-up

Background

Pain in the orofacial region is often reported after whiplash trauma. However, prospective studies evaluating clinical signs related to orofacial pain and disability in whiplash populations are rare. The aim of the present study was to evaluate clinical signs related to pain and dysfunction in orofacial and neck regions after whiplash trauma, in a short- and long-term perspective.

Methods

In total, 84 cases (48 women) diagnosed with neck distortion after a car accident and 116 controls (68 women) were examined within 1 month, and 49 cases (27 women) and 71 controls (41 women) were re-examined 2 years later. Outcome measures were pain on palpation of jaw and neck muscles and maximal jaw opening. Analysis was performed using mixed-models.

Results

Cases and women were at higher risk for pain on palpation of jaw muscles (OR:7.7; p < 0.001 and OR:3.2; p = 0.010 respectively) and neck muscles (OR:12.7; p < 0.001 and OR:2.9; p = 0.020 respectively) but with no significant effect of time. Cases and women also had lower maximal jaw opening (−3.1; p = 0.001 and −3.3; p = 0.001 respectively). There was no significant time effect, but a significant interaction between cases and time (2.2; p = 0.004).

Conclusion

Individuals with a whiplash trauma present a higher risk for pain on palpation in jaw and neck muscles both in a short- and long-term perspective, but show normal jaw movements. No time effect suggests that cases do not spontaneously improve nor get worse. Investigating pain on palpation in the jaw and neck muscles after whiplash trauma can identify individuals at risk for developing long-term orofacial pain and dysfunction.

Significance

Orofacial pain is often reported after whiplash trauma but most previous studies concerning orofacial pain in whiplash populations have been questionnaire studies. Cases with a previous whiplash trauma and women, in general, had higher risk for pain on palpation in the jaw and neck region. Investigating pain on palpation after a whiplash trauma can help to identify individuals at risk of developing long-lasting pain in the orofacial region.     

Diagnosis of paediatric airway foreign body: is it easy?

Foreign-body aspiration in children results in diagnostic problems, mainly because of nonspecific signs. Therefore, in this study, we placed particular stress on false-positive and -negative predictors. Charts of 139 consecutive paediatric patients aged 6.0 months to 15.5 years who underwent bronchoscopy for a suspected foreign body aspiration were analysed retrospectively. A foreign body was found in 95 cases (68%). The anamnesis was positive in 91%. Cough was the most common clinical symptom (91%) with a sensitivity and specificity of 94% and 23%, respectively. There were no significant correlations between clinical symptoms and the locations of foreign bodies. The majority of focal hyperinflation (24%) and atelectasis (15%) were seen in chest radiographs, with a sensitivity and specificity of 33% and 89% (hyperinflation) and 15% and 82% (atelectasis), respectively. Chest X-rays were normal in 46 cases; however, an object was removed in 25. Persistent infiltrates were present in 14 X-rays, and a foreign body was extracted during bronchoscopy in 4. A highly significant correlation between the type of foreign body and radiological signs was noted (p = 0.00001). Anamnesis, clinical symptoms, and radiological findings are helpful in confirming aspiration, but can be misleading. Chronic or recurrent pneumonia should prompt further bronchoscopic diagnosis.