Chronic fetal exposure to Ureaplasma parvum suppresses innate immune responses in sheep

The chorioamnionitis associated with preterm delivery is often polymicrobial with ureaplasma being the most common isolate. To evaluate interactions between the different proinflammatory mediators, we hypothesized that ureaplasma exposure would increase fetal responsiveness to LPS. Fetal sheep were given intra-amniotic (IA) injections of media (control) or Ureaplasma parvum serovar 3 either 7 or 70 d before preterm delivery. Another group received an IA injection of Escherichia coli LPS 2 d prior to delivery. To test for interactions, IA U. parvum-exposed animals were challenged with IA LPS and delivered 2 d later. All animals were delivered at 124 ± 1-d gestation (term = 150 d). Compared with the 2-d LPS exposure group, the U. parvum 70 d + LPS group had 1) decreased lung pro- and anti-inflammatory cytokine expression and 2) fewer CD3(+) T lymphocytes, CCL2(+), myeloperoxidase(+), and PU.1(+) cells in the lung. Interestingly, exposure to U. parvum for 7 d did not change responses to a subsequent IA LPS challenge, and exposure to IA U. parvum alone induced mild lung inflammation. Exposure to U. parvum increased pulmonary TGF-β1 expression but did not change mRNA expression of either the receptor TLR4 or some of the downstream mediators in the lung. Monocytes from fetal blood and lung isolated from U. parvum 70 d + LPS but not U. parvum 7 d + LPS animals had decreased in vitro responsiveness to LPS. These results are consistent with the novel finding of downregulation of LPS responses by chronic but not acute fetal exposures to U. parvum. The findings increase our understanding of how chorioamnionitis-exposed preterm infants may respond to lung injury and postnatal nosocomial infections.     

Doxorubicin,DNA torsion,and chromatin dynamics

Doxorubicin is one of the most important anti-cancer chemotherapeutic drugs, being widely used for the treatment of solid tumors and acute leukemias. The action of doxorubicin and other anthracycline drugs has been intensively investigated during the last several decades, but the mechanisms that have been proposed for cell killing remain disparate and controversial. In this review, we examine the proposed models for doxorubicin action from the perspective of the chromatin landscape, which is altered in many types of cancer due to recurrent mutations in chromatin modifiers. We highlight recent evidence for effects of anthracyclines on DNA torsion and chromatin dynamics that may underlie basic mechanisms of doxorubicin-mediated cell death and suggest new therapeutic strategies for cancer treatment.     

Highly specific and sensitive method for measuring nucleotide excision repair kinetics of ultraviolet photoproducts in human cells

The nucleotide excision repair pathway removes ultraviolet (UV) photoproducts from the human genome in the form of short oligonucleotides ∼30 nt in length. Because there are limitations to many of the currently available methods for investigating UV photoproduct repair in vivo, we developed a convenient non-radioisotopic method to directly detect DNA excision repair events in human cells. The approach involves extraction of oligonucleotides from UV-irradiated cells, DNA end-labeling with biotin and streptavidin-mediated chemiluminescent detection of the excised UV photoproduct-containing oligonucleotides that are released from the genome during excision repair. Our novel approach is robust, with essentially no signal in the absence of UV or a functional excision repair system. Furthermore, our non-radioisotopic methodology allows for the sensitive detection of excision products within minutes following UV irradiation and does not require additional enrichment steps such as immunoprecipitation. Finally, this technique allows for quantitative measurements of excision repair in human cells. We suggest that the new techniques presented here will be a useful and powerful approach for studying the mechanism of human nucleotide excision repair in vivo.     

Skin structure in the snout of the Australian lungfish,Neoceratodus forsteri (Osteichthyes: Dipnoi)

Many fossil lungfish have a system of mineralised tubules in the dermis of the snout, branching extensively and radiating towards the epidermis. The tubules anastomose in the superficial layer of the dermis, forming a plexus consisting of two layers of vessels, with branches that expand into pore canals and flask organs, flanked by cosmine nodules where these are present. Traces of this system are found in the Australian lungfish, Neoceratodus forsteri, consisting of branching tubules in the dermis, a double plexus below the epidermis and dermal papillae entering the epidermis without reaching the surface. In N. forsteri, the tubules, the plexus and the dermal papillae consist of thick, unmineralised connective tissue, enclosing fine blood vessels packed with lymphocytes. Tissues in the epidermis and the dermis of N. forsteri are not associated with deposits of calcium, which is below detectable limits in the skin of the snout at all stages of the life cycle. Canals of the sensory line system, with mechanoreceptors, are separate from the tubules, the plexus and the dermal papillae, as are the electroreceptors in the epidermis. The system of tubules, plexus, dermal papillae and lymphatic capillaries may function to protect the tissues of the snout from infection.     

Women Commencing Anastrozole,Letrozole or Tamoxifen for Early Breast Cancer: The Impact of Comorbidity and Demographics on Initial Choice

Background

Australian clinical guidelines recommend endocrine therapy for all women with hormone-dependent early breast cancer. Guidelines specify tamoxifen as first-line therapy for pre-menopausal women, and tamoxifen or an aromatase inhibitor (AI) for post-menopausal women depending on the risk of recurrence based on tumour characteristics including size. Therapies have different side effect profiles; therefore comorbidity may also influence choice. We examined comorbidity, and the clinical and demographic characteristics of women commencing different therapies.

Patients and Methods

We identified the first dispensing of tamoxifen, anastrozole or letrozole for women diagnosed with invasive breast cancer in the 45 and Up Study from 2004–2009 (N = 1266). Unit-level pharmacy and medical service claims, hospital, Cancer Registry, and self-reported data were linked to determine menopause status at diagnosis, tumour size, age, comorbidities, and change in subsidy restrictions. Chi-square tests and generalised regression models were used to compare the characteristics of women commencing different therapies.

Results

Most pre-menopausal women commenced therapy with tamoxifen (91%). Anastrozole was the predominant therapy for post-menopausal women (57%), followed by tamoxifen (28%). Women with osteoporosis were less likely to commence anastrozole compared with tamoxifen (anastrozole RR = 0.7, 95% CI = 0.5–0.9). Women with arthritis were 1.6-times more likely to commence letrozole than anastrozole (95% CI = 1.1–2.1). Tamoxifen was more often initiated in women with tumours >1 cm, who were also ≥75 years. Subsidy restriction changes were associated with substantial increases in the proportion of women commencing AIs (anastrozole RR = 4.3, letrozole RR = 8.3).

Conclusions

The findings indicate interplay of comorbidity and therapy choice for women with invasive breast cancer. Most post-menopausal women commenced therapy with anastrozole; however, letrozole and tamoxifen were more often initiated for women with comorbid arthritis and osteoporosis, respectively. Tamoxifen was also more common for women with tumours >1 cm and aged ≥75 years. Subsidy restrictions appear to have strongly influenced therapy choice.     

Sustained Inflation at Birth Did Not Alter Lung Injury from Mechanical Ventilation in Surfactant-Treated Fetal Lambs

Background

Sustained inflations (SI) are used with the initiation of ventilation at birth to rapidly recruit functional residual capacity and may decrease lung injury and the need for mechanical ventilation in preterm infants. However, a 20 second SI in surfactant-deficient preterm lambs caused an acute phase injury response without decreasing lung injury from subsequent mechanical ventilation.

Hypothesis

A 20 second SI at birth will decrease lung injury from mechanical ventilation in surfactant-treated preterm fetal lambs.

Methods

The head and chest of fetal sheep at 126±1 day GA were exteriorized, with tracheostomy and removal of fetal lung fluid prior to treatment with surfactant (300 mg in 15 ml saline). Fetal lambs were randomized to one of four 15 minute interventions: 1) PEEP 8 cmH₂O; 2) 20 sec SI at 40 cmH₂O, then PEEP 8 cmH₂O; 3) mechanical ventilation with 7 ml/kg tidal volume; or 4) 20 sec SI then mechanical ventilation at 7 ml/kg. Fetal lambs remained on placental support for the intervention and for 30 min after the intervention.

Results

SI recruited a mean volume of 6.8±0.8 mL/kg. SI did not alter respiratory physiology during mechanical ventilation. Heat shock protein (HSP) 70, HSP60, and total protein in lung fluid similarly increased in both ventilation groups. Modest pro-inflammatory cytokine and acute phase responses, with or without SI, were similar with ventilation. SI alone did not increase markers of injury.

Conclusion

In surfactant treated fetal lambs, a 20 sec SI did not alter ventilation physiology or markers of lung injury from mechanical ventilation.