Genomic Regions That Underlie Soybean Seed Isoflavone Content

Soy products contain isoflavones (genistein, daidzein, andglycitein) that display biological effects when ingested byhumans and animals, these effects are species, dose and agedependent. Therefore, the content and quality of isoflavones insoybeans is a key to their biological effect. Our objective wasto identify loci that underlie isoflavone content in soybeanseeds. The study involved 100 recombinant inbred lines (RIL) fromthe cross of ‘Essex' by ‘Forrest,' two cultivars that contrastfor isoflavone content. Isoflavone content of seeds from each RILwas determined by high performance liquid chromatography (HPLC).The distribution of isoflavone content was continuous andunimodal. The heritability estimates on a line mean basis were79% for daidzein, 22% for genistein, and 88% for glycitein.Isoflavone content of soybean seeds was compared against 150polymorphic DNA markers in a one-way analysis of variance. Fourgenomic regions were found to be significantly associated withthe isoflavone content of soybean seeds across both locations andyears. Molecular linkage group B1 contained a major QTLunderlying glycitein content (P = 0.0001, R² = 50.2%), linkagegroup N contained a QTL for glycitein (P = 0.0033, R² = 11.1%)and a QTL for daidzein (P = 0.0023, R² = 10.3%) and linkagegroup A1 contained a QTL for daidzein (P = 0.0081, R² = 9.6%).Selection for these chromosomal regions in a marker assistedselection program will allow for the manipulation of amounts andprofiles of isoflavones (genistein, daidzein, and glycitein)content of soybean seeds. In addition, tightly linked markers canbe used in map based cloning of genes associated withisoflavone content.     

Different modulation by histamine of IL-4 and interferon-gamma (IFN-γ) release according to the phenotype of human Th0, Th1 and Th2 clones

Histamine, an important inflammatory mediator in allergic diseases and asthma, has been reported to have modulator effects on T cells, suggesting that the bronchial microenvironment may regulate the function of resident T cells. We examined the effect of histamine on the release of the Th2-associated cytokines IL-4 and IL-5 and the Th1-associated cytokine IFN-γ by 30 CD4⁺ T cell clones from peripheral blood or bronchial biopsy of one atopic subject. Based on the IL-4/IFN-γ ratio, the clones were ascribed to the Th2 (ratio >1), Th0 (ratio 0.1 and 1) or Th1 (ratio <0.1) phenotype. Histamine inhibited IFN-γ production by Th1-like cells (P<0.02, Kruskall–Wallis), especially from bronchial biopsy, but had no effect on IL-4 release. Regarding Th0 clones, histamine inhibited IL-4 production (P<0.02) in a dose-dependent manner and slightly inhibited IFN-γ production, but had no effect on Th2-like cells. Histamine had a heterogeneous and insignificant effect on IL-5 production. The H₂-receptor antagonist ranitidine completely reversed the inhibition of IL-4 and IFN-γ production, whereas the agonist dimaprit mimicked this effect. In contrast, H₁- and H₃-receptor agonists and antagonists had no significant effect. These data demonstrate that histamine has different effects on IL-4 and IFN-γ release by T helper cells according to their phenotype via H₂-receptors. This study extends the immunomodulatory effects of histamine which may contribute to the perpetuation of airway inflammation in asthma.     

The role of size, sequence and haplotype in the stability of FRAXA and FRAXE alleles during transmission

Factors involved in the stability of trinucleotide repeats during transmission were studied in 139 families in which a full mutation, premutation or intermediate allele at either FRAXA or FRAXE was segregating. The transmission of alleles at FRAXA, FRAXE and four microsatellite loci were recorded for all individuals. Instability within the minimal and common ranges (0-40 repeats for FRAXA, 0-30 repeats for FRAXE) was extremely rare; only one example was observed, an increased in size at FRAXA from 29 to 39 repeats. Four FRAXA and three FRAXE alleles in the intermediate range (41-60) repeats for FRAXA, 31-60 for FRAXE) were unstably transmitted. Instability was more frequent for FRAXA intermediate alleles that had a tract of pure CGG greater than 37 although instability only occurred in two of 13 such transmissions: the changes observed were limited to only one or two repeats. Premutation FRAXA alleles over 100 repeats expanded to a full mutation during female transmission in 100% of cases, in agreement with other published series. There was no clear correlation between haplotype and probability of expansion of FRAXA premutations. Instability at FRAXA or FRAXE was more often observed in conjunction with a second instability at an independent locus suggesting genomic instability as a possible mechanism by which at least some FRAXA and FRAXE mutations arise.      

Nosocomial respiratory syncytial virus infection in Canadian pediatric hospitals: a Pediatric Investigators Collaborative Network on Infections in Canada Study

OBJECTIVE: To determine nosocomial transmission of respiratory syncytial virus (RSV) in Canadian pediatric hospitals, outcomes associated with nosocomial disease, and infection control practices. DESIGN: A prospective cohort study in the 1992 to 1994 winter respiratory seasons. SETTING: Nine Canadian pediatric university-affiliated hospitals. PARTICIPANTS: Hospitalized children with symptoms of lower respiratory tract infection (at least one of cough, wheezing, dyspnea, tachypnea, and apnea) and RSV antigen identified in a nasopharyngeal aspirate. RESULTS: Of 1516 children, 91 (6%) had nosocomial RSV (NRSV), defined as symptoms of lower respiratory tract infection and RSV antigen beginning >72 hours after admission. The nosocomial ratio (NRSV/[com-munity-acquired RSV {CARSV})] + NRSV) varied by site from 2.8% to 13%. The median length of stay attributable to RSV for community-acquired illness was 5 days, but 10 days for nosocomial illness. Four children with NRSV (4. 4%) died within 2 weeks of infection, compared with 6 (0.42%) with CARSV (relative risk = 10.4, 95% confidence interval: 3.0, 36.4). All sites isolated RSV-positive patients in single rooms or cohorted them. In a multivariate model, no particular isolation policy was associated with decreased nosocomial ratio, but gowning to enter the room was associated with increased risk of RSV transmission (incidence rate ratio 2.81; confidence interval: 1.65, 4.77). CONCLUSIONS: RSV transmission risk in Canadian pediatric hospitals is generally low. Although use of barrier methods varies, all sites cohort or isolate RSV-positive patients in single rooms. Children with risk factors for severe disease who acquire infection nosocomially have prolonged stays and excess mortality.     

An outbreak of shigellosis in a child care centre.

Outbreaks of shigellosis in child care are not commonly reported in Australia, however Shigella bacteria can easily spread in these settings. We report an outbreak of shigellosis in a child care centre and discuss the control measures implemented. This investigation identified 20 confirmed cases of Shigella sonnei biotype g and a further 47 probable cases in children and staff who attended a child care centre, and their household contacts. The investigation highlighted the importance of stringent control measures and protocols for dealing with outbreaks of Shigella and other enteric infections in the child care setting, and the importance of prompt notification by both doctors and child care centres, of suspected outbreaks.     

Sloping ABR baselines and the ECG myogenic artefact

Objective: To investigate the possibility that a sloping baseline in an ABR recording has its origins in cardiac activity and if so, identify how it is expressed. Design: The effect of ECG removal on the averaged ABR was investigated at two artefact rejection levels. Study sample: Ten 1-minute records of raw EEG containing ABR responses but contaminated with cardiac activity were recorded from babies under 12 weeks of age and re-averaged using two artefact rejection levels. The slope of the ABR recording was measured. The measurements were repeated after removing effectively the cardiac activity from the records. Results: A sloping baseline was observed at one or both artefact rejection levels in all records. The slope varied as the artefact rejection level was changed, suggesting this may be implicated in slope generation. The slope effectively disappeared when the cardiac activity was removed from the record. Conclusions: Cardiac activity has the potential to cause a sloping ABR baseline. A possible explanation for this effect is offered, together with suggestions for tester strategy when a sloping ABR baseline is seen in a clinical setting.