Elevated leukotriene B4 and 8-isoprostane in exhaled breath condensate from preterm-born infants

BACKGROUND

Inflammation and oxidative stress play a key role in the development of bronchopulmonary dysplasia (BPD), possibly contributing to persistent respiratory morbidity after preterm birth. We aimed to assess if inflammatory markers were elevated in exhaled breath condensate (EBC) of infants born very prematurely (< 32 weeks gestation) at 12-16 corrected months of age, and if increased levels were associated with BPD diagnosis and respiratory morbidity.

METHODS

EBC samples and respiratory questionnaires were collected from 15 term-born infants and 33 preterm-born infants, 12 with a neonatal BPD diagnosis. EBC samples were analysed for leukotriene B4 (inflammation) and 8-isoprostane (oxidative stress) concentrations using enzyme-linked immune-assays. Differences between groups were analysed by Kruskal-Wallis Test with post-hoc comparisons, independent samples t-test or Mann-Whitney U test depending on normality of the data.

RESULTS

Leukotriene B4 and 8-isoprostane levels were elevated in exhaled breath condensate of preterm-born infants compared to those born at term (mean difference [95% CI]; 1.52 [0.45, 2.59], p = 0.02; 0.77 [0.52, 1.02], p < 0.001, respectively). Leukotriene B4 and 8-isoprostane levels were independent of BPD diagnosis and respiratory morbidity over the first year of life.

CONCLUSIONS

Infants born very prematurely exhibit elevated markers of airway neutrophilic inflammation and oxidative stress beyond the first year of life, regardless of a neonatal diagnosis of chronic lung disease or respiratory morbidity during infancy. These findings may have implications for future lung health.

TRIAL REGISTRATION

N/A.

Persistent and progressive long-term lung disease in survivors of preterm birth

Preterm birth accounts for approximately 11% of births globally, with rates increasing across many countries. Concurrent advances in neonatal care have led to increased survival of infants of lower gestational age (GA). However, infants born <32 weeks of GA experience adverse respiratory outcomes, manifesting with increased respiratory symptoms, hospitalisation and health care utilisation into early childhood. The development of bronchopulmonary dysplasia (BPD) - the chronic lung disease of prematurity - further increases the risk of poor respiratory outcomes throughout childhood, into adolescence and adulthood. Indeed, survivors of preterm birth have shown increased respiratory symptoms, altered lung structure, persistent and even declining lung function throughout childhood. The mechanisms behind this persistent and sometimes progressive lung disease are unclear, and the implications place those born preterm at increased risk of respiratory morbidity into adulthood. This review aims to summarise what is known about the long-term pulmonary outcomes of contemporary preterm birth, examine the possible mechanisms of long-term respiratory morbidity in those born preterm and discuss addressing the unknowns and potentials for targeted treatments.

Medial temporal lobe atrophy on MRI scans and the diagnosis of Alzheimer disease

BACKGROUND

Despite convenience, accessibility, and strong correlation to severity of Alzheimer disease (AD) pathology, medial temporal lobe atrophy (MTA) has not been used as a criterion in the diagnosis of prodromal and probable AD.

METHODS

Using a newly validated visual rating system, mean MTA scores of three bilateral medial temporal lobe structures were compared for subjects with no cognitive impairment (NCI) (n = 117), nonamnestic mild cognitive impairment (MCI) (n = 46), amnestic MCI (n = 45), and probable AD (n = 53). Correlations between MTA scores and neuropsychological test scores at baseline, and predictors of change in diagnosis at 1-year follow-up were evaluated.

RESULTS

With NCI as the reference group, a mean MTA cut score of 1.33 yielded an optimal sensitivity/specificity of 85%/82% for probable AD subjects and 80%/82% for amnestic MCI subjects. MTA and Clinical Dementia Rating Sum of Boxes scores at baseline were independent and additive predictors of diagnosis at baseline, and of transition from NCI to MCI or from MCI to dementia at 1-year follow-up.

CONCLUSION

Medial temporal lobe atrophy (MTA) scores 1) distinguish probable Alzheimer disease (AD) and amnestic mild cognitive impairment (MCI) subjects from nonamnestic MCI and no cognitive impairment (NCI) subjects, 2) help predict diagnosis at baseline, and 3) predict transition from NCI to MCI and from MCI to probable AD. MTA scores should be used as a criterion in the clinical diagnosis of AD.

First Report of Aerial Blight Caused by Pythium myriotylum on Tomato in Florida

In September 1996 and 1997, diseased tomato seedlings were observed with symptoms of an aerial watery rot on leaves, petioles, and stems. Tomato cvs. Sanibel and 10097 from commercial fields in southwest Florida (Collier and Lee counties) and west central Florida (Manatee County) exhibited similar symptoms that occurred at an incidence of 15 to 18% about 4 weeks after transplanting and resulted in plant death. Microscopic examination of symptomatic tissue revealed the presence of mycelium and oogonia typical of Pythium spp. A fungus was consistently isolated from four plants sampled from each site onto a medium selective for Pythium spp. and maintained in pure culture on V8 juice agar at 28°C. The isolates were identified as Pythium myriotylum Drechs. based on the following morphological data: lobate sporangium, 12 to 13 μm wide; vesicle 15.4 to 19.4 μm in diameter; exit tube 54 to 90 μm long, oogonium 23 to 30 μm in diameter; and oospore 21 to 26 μm in diameter (1,2). Pathogenicity tests were conducted with two isolates from diverse regions within Florida by spray inoculating the leaves and shoots of 6- to 8-week-old tomato seedlings with a sporangial suspension of 1 × 10⁴ sporangia per ml. Noninoculated plants served as controls. Plants had 24 h of pre- and post-dark period, day/night temperatures of 28/21°C, a 14-h photoperiod, and near 100% relative humidity in a growth chamber. The foliage of inoculated tomato plants exhibited symptoms identical to those observed in field samples 24 h after inoculation and 100% mortality within 72 h. The reisolated fungus was morphologically identical to the original isolate. Noninoculated plants remained asymptomatic. The unusual rainfall recorded at some sites, such as in Manatee County in September 1997, was 36% higher than the 40-year average and may have contributed to the incidence of this previously undescribed foliar blight. References: (1) Anonymous. C.M.I. Descriptions of Pathogenic Fungi and Bacteria No. 118. (2) T. Watanabe. Pictorial Atlas of Soil Fungi. Lewis Pub., London. p. 71.