Regulation of Cisplatin Resistance in Lung Cancer Cells by Nicotine, BDNF, and a β-Adrenergic Receptor Blocker

It is well-recognized that cigarette smoking is a primary risk factor in the development of non-small cell lung cancer (NSCLC), known to account for ~80% of all lung cancers with nicotine recognized as the major addictive component. In investigating the effect of nicotine, brain-derived neurotrophic factor (BDNF), and the β-adrenergic receptor blocker, propranolol, on sensitivity of NSCLC cell lines, A549 and H1299, to cisplatin, we found increased cell viability, and enhanced cisplatin resistance with nicotine and/or BDNF treatment while opposite effects were found upon treatment with propranolol. Cell treatment with epinephrine or nicotine led to EGFR and IGF-1R activation, effects opposite to those found with propranolol. Blocking EGFR and IGF-1R activation increased cell sensitivity to cisplatin in both cell lines. PI3K and AKT activities were upregulated by nicotine or BDNF and downregulated by cell treatment with inhibitors against EGFR and IGF-1R and by propranolol. Apoptosis and cell sensitivity to cisplatin increased upon co-treatment of cells with cisplatin and inhibitors against PI3K or AKT. Our findings shed light on an interplay between nicotine, BDNF, and β-Adrenergic receptor signaling in regulating survival of lung cancer cells and chemoresistance which can likely expand therapeutic opportunities that target this regulatory network in the future.

The timing of skin acidification in very low birth weight infants

OBJECTIVE

The purpose of this study was to examine the development of the pH mantle of the skin in very low birth weight (VLBW) infants.

STUDY DESIGN

Forty VLBW infants underwent repeated measurements of skin pH over the first month of life using a glass flat-surface pH electrode. Six skin sites were measured, daily for the first week of life and then twice weekly for the next 3 weeks.

RESULTS

The only factor that affected the initial skin pH was sex, with males having a significantly higher pH at birth. Over time, birth weight, skin area, and postnatal age had significant effects on skin pH. The pattern of postnatal change in skin pH was similar to that described in term infants, a rapid decrease in pH over the first week followed by a more gradual decrease over the next 3 weeks.

CONCLUSION

The development of the skin's acid mantle in VLBW infants occurs rapidly during postnatal life and closely mimics the pattern seen at term.

Herpes simplex type II infection in monozygotic twins

The unusual occurrence of herpes simplex virus (HSV) type II infection in a set of monozygotic premature twins is described. The cases highlight the difficulty of early diagnosis of HSV disease in the absence of a positive maternal history and cutaneous lesions. Risk factors for mortality and morbidity are discussed.