Pericardin, a Drosophila collagen, facilitates accumulation of hemocytes at the heart.

Hematopoietic cell lineages support organismal needs by responding to positional and systemic signals that balance proliferative and differentiation events. Drosophila provides an excellent genetic model to dissect these signals, where the activity of cues in the hemolymph or substrate can be traced to determination and differentiation events of well characterized hemocyte types. Plasmatocytes in third instar larvae increase in number in response to infection and in anticipation of metamorphosis. Here we characterize hemocyte clustering, proliferation and transdifferentiation on the heart or dorsal vessel. Hemocytes accumulate on the inner foldings of the heart basement membrane, where they move with heart contraction, and are in proximity to the heart ostia and pericardial nephrocytes. The numbers of hemocytes vary, but increase transiently before pupariation, and decrease by 4 h before pupa formation. During their accumulation at the heart, plasmatocytes can proliferate and can transdifferentiate into crystal cells. Serrate expressing cells as well as lamellocyte-like, Atilla expressing ensheathing cells are associated with some, but not all hemocyte clusters. Hemocyte aggregation is enhanced by the presence of a heart specific Collagen, Pericardin, but not the associated pericardial cells. The varied and transient number of hemocytes in the pericardial compartment suggests that this is not a hematopoietic hub, but a niche supporting differentiation and rapid dispersal in response to systemic signals.

Bevacizumab + capecitabine as maintenance therapy after initial bevacizumab + XELOX treatment in previously untreated patients with metastatic colorectal cancer: phase III 'Stop and Go' study results--a Turkish Oncology Group Trial.

OBJECTIVE: It was the aim of this study to evaluate maintenance therapy with bevacizumab + capecitabine following induction with bevacizumab + capecitabine + oxaliplatin (XELOX) versus bevacizumab + XELOX until progression as first-line therapy in metastatic colorectal cancer (mCRC). METHODS: Patients received either bevacizumab (7.5 mg/kg) + XELOX (capecitabine 1,000 mg/m(2) twice daily on days 1-14 + oxaliplatin 130 mg/m(2) on day 1 every 3 weeks) until disease progression (arm A) or the same doses of bevacizumab + XELOX for 6 cycles followed by bevacizumab + capecitabine until disease progression (arm B). The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), objective response rate (ORR) and safety. RESULTS: One hundred and twenty-three patients were randomized. Treatment compliance was similar in both groups. Median PFS was significantly longer for arm B than for arm A (11.0 vs. 8.3 months; p = 0.002). There was no significant difference between the two arms for ORR (66.7 vs. 59.0%; p = 0.861) or median OS (23.8 vs. 20.2 months; p = 0.100). Tolerability was acceptable in both treatment arms; the most frequent grade 3/4 treatment-related adverse events (arm B vs. arm A) were fatigue (6.6 vs. 16.1%), diarrhoea (3.3 vs. 11.3%), anorexia (3.3 vs. 11.3%), and neuropathy (1.6 vs. 8.1%). CONCLUSIONS: Maintenance therapy with bevacizumab + capecitabine can be considered an appropriate option following induction bevacizumab + XELOX in patients with mCRC instead of continuation of bevacizumab + XELOX.

Chloroform and desflurane immobilization with recovery of viable Drosophila larvae for confocal imaging.

Imaging of living, intact Drosophila larvae is challenged if normal bodily function must be observed or when healthy larvae must be recovered for subsequent studies. Here, we describe a simple and short protocol that employs transient airborne chloroform or desflurane (1,2,2,2-tetrafluoroethyl difluoromethyl ether) to efficiently immobilize larvae without the use of manipulation devices, vaporizers or imaging chambers. This non-lethal method allows the use of anesthetics while allowing tracking of individual Drosophila into adulthood for follow-up experiments. At dosages sufficient to immobilize larvae, Desflurane, but not chloroform reduced the central nervous system response to auditory stimulus. Desflurane doses were sufficient to arrest the heart, however significant rapid recovery was observed. With our method, chloroform provided more rapid anesthesia but slower recovery than Desflurane. Without specialized hardware, this technique allows for repeated imaging of living Drosophila larvae.

Talin Is Required Continuously for Cardiomyocyte Remodeling during Heart Growth in Drosophila.

Mechanotransduction of tension can govern the remodeling of cardiomyocytes during growth or cardiomyopathy. Tension is signaled through the integrin adhesion complexes found at muscle insertions and costameres but the relative importance of signalling during cardiomyocyte growth versus remodelling has not been assessed. Employing the Drosophila cardiomyocyte as a genetically amenable model, we depleted the levels of Talin, a central component of the integrin adhesion complex, at different stages of heart growth and remodeling. We demonstrate a continuous requirement for Talin during heart growth to maintain the one-to-one apposition of myofibril ends between cardiomyocytes. Retracted myofibrils cannot regenerate appositions to adjacent cells after restoration of normal Talin expression, and the resulting deficit reduces heart contraction and lifespan. Reduction of Talin during heart remodeling after hatching or during metamorphosis results in pervasive degeneration of cell contacts, myofibril length and number, for which restored Talin expression is insufficient for regeneration. Resultant dilated cardiomyopathy results in a fibrillating heart with poor rhythmicity. Cardiomyocytes have poor capacity to regenerate deficits in myofibril orientation and insertion, despite an ongoing capacity to remodel integrin based adhesions.

Plasma markers of NO synthase activity in women after ovarian hyperstimulation: influence of estradiol on ADMA.

The beneficial effects of estrogen on vasculature are partially explained by an estrogen-induced increase in nitric oxide (NO) synthesis. Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of NO synthase. In the present study, the effect of 17beta-estradiol (E2) on ADMA and NO synthesis was investigated both in vivo and in vitro. Plasma NO and ADMA levels were measured in healthy women at a low menstrual estrogenic stage (E2 < 100 pg/ml) and in women who were undergoing ovarian hyperstimulation (E2 > 2000 pg/ml) before in vitro fertilization embryo transfer. Primary human umbilical vein endothelial cell (HUVEC) cultures were incubated with and without 100 nM E2 for 24 hours and the NO and ADMA levels of the media were measured. A nitric oxide analyzer was used for the detection of NO metabolites. ADMA and L-arginine were measured by high-performance liquid chromatography after precolumn derivatization with o-phthaldialdehyde. The IVF patients with high plasma E2 concentrations had significantly lower (48%, n = 12) plasma ADMA and higher (56%, n = 14) NO levels than the women at a low estrogenic stage. The incubation of HUVEC cultures with estradiol resulted in a significant decrease (47%, n = 10) in ADMA and an increase (46%, n = 10) in NO concentration in the culture media. Estradiol, by reducing ADMA, may therefore facilitate NO synthesis in endothelial cells. The protective effects of estradiol on vasculature may partly be related to a reduction in ADMA levels.