The Arabidopsis PHYTOCHROME KINASE SUBSTRATE2 protein is a phototropin signaling element that regulates leaf flattening and leaf positioning

In Arabidopsis (Arabidopsis thaliana), the blue light photoreceptor phototropins (phot1 and phot2) fine-tune the photosynthetic status of the plant by controlling several important adaptive processes in response to environmental light variations. These processes include stem and petiole phototropism (leaf positioning), leaf flattening, stomatal opening, and chloroplast movements. The PHYTOCHROME KINASE SUBSTRATE (PKS) protein family comprises four members in Arabidopsis (PKS1-PKS4). PKS1 is a novel phot1 signaling element during phototropism, as it interacts with phot1 and the important signaling element NONPHOTOTROPIC HYPOCOTYL3 (NPH3) and is required for normal phot1-mediated phototropism. In this study, we have analyzed more globally the role of three PKS members (PKS1, PKS2, and PKS4). Systematic analysis of mutants reveals that PKS2 (and to a lesser extent PKS1) act in the same subset of phototropin-controlled responses as NPH3, namely leaf flattening and positioning. PKS1, PKS2, and NPH3 coimmunoprecipitate with both phot1-green fluorescent protein and phot2-green fluorescent protein in leaf extracts. Genetic experiments position PKS2 within phot1 and phot2 pathways controlling leaf positioning and leaf flattening, respectively. NPH3 can act in both phot1 and phot2 pathways, and synergistic interactions observed between pks2 and nph3 mutants suggest complementary roles of PKS2 and NPH3 during phototropin signaling. Finally, several observations further suggest that PKS2 may regulate leaf flattening and positioning by controlling auxin homeostasis. Together with previous findings, our results indicate that the PKS proteins represent an important family of phototropin signaling proteins.

Fatal pulmonary embolism in a premature neonate after twin-to-twin transfusion syndrome

Thrombotic events are being increasingly recognized during the neonatal period. An infant girl was born at 29 weeks' gestation after a pregnancy complicated by twin-to-twin transfusion syndrome. After an initial uncomplicated clinical course, her oxygen requirement increased, which was interpreted as an early sign of bronchopulmonary dysplasia. At 3 weeks of age, she suddenly collapsed and died of severe pulmonary hypertension. At autopsy, multiple pulmonary artery emboli and several older renal vein thromboses were found. Results of genetic analyses of the infant and her family were negative for thrombophilia. Although embolism represents a frequent emergency in adults, fatal pulmonary embolism has never, to our knowledge, been described for premature infants. This case suggests that thrombotic events are underdiagnosed and that additional studies are needed to define infants at risk and optimal treatment strategies.

Improving cup positioning using a mechanical navigation instrument

Although surgical navigation reduces the rate of malpositioned acetabular cups in total hip arthroplasty (THA), its use has not been widely adopted. As a result of our perceived need for simple and efficient methods of navigation, we developed a mechanical navigation device for acetabular cup orientation.

Reproducibility of sensory nerve conduction studies of the sural nerve using ultrasound-guided needle positioning

In this study we sought to evaluate the reproducibility of sensory nerve conduction studies (NCS) using ultrasound-guided needle positioning (USNP).

Percutaneous radiofrequency ablation of virtual tumours in canine kidney using Global Positioning System-like technology

What's known on the subject? And what does the study add? We have previously shown that percutaneous radiofrequency ablation guided by image-fusion technology allows for precise needle placement with real time ultrasound superimposed with pre-loaded imaging, removing the need for real-time CT or MR guidance. Emerging technology also allows real-time tracking of a treatment needle within an organ in a virtually created 3D format. To our knowledge, this is the first study utilising a sophisticated ultrasound-based navigation system that uses both image-fusion and real-time probe-tracking technologies for in-vivo renal ablative intervention.

[Complex umbilical cord vein pulsations in cases with twin-twin transfusion syndrome: prognostic implications]

Umbilical vein pulsations (UV-P) are due to various etiologies. The aim of the present study was to investigate the incidence and type of UV-P in monochorionic twins with twin-twin transfusion syndrome (TTTS).

Single umbilical artery in twin pregnancies

Our purpose was to evaluate the antenatal incidence of single umbilical artery (SUA) in twin pregnancies according to chorionicity and to assess its relationship with outcome.