Robot-assisted craniotomy.

In the Special Research Centre 414 of the German Research Funding (DFG, Bonn) a system for robot-assisted cranial surgery was developed. It is designed for the accurate and safe execution of craniotomies and repositioning of bone pieces. The system is intended for use in the surgical therapy of craniosynostosis. Preoperatively, CT imaging is performed. In a computerized planning system the position and shape of the intended craniotomy is intuitively planned on a virtual model of the patient's skull. Intraoperatively, after conventional removal of the covering soft tissue, the robot performs the craniotomy autonomously. Extensive testing in phantom studies and animal tests confirmed the reliability and accuracy of the system. A thorough risk analysis of the system was performed. In this paper, the first clinical use of the system on a patient is described and the clinical importance is discussed.

Initial amplification of duck hepatitis B virus covalently closed circular DNA after in vitro infection of embryonic duck hepatocytes is increased by cell cycle progression.

The relationship between the cell cycle and early amplification of duck hepatitis B virus covalently closed circular (CCC) DNA was studied after in vitro infection of fetal hepatocytes. We first showed that embryonic hepatocytes proliferated for at least 6 days after plating and that complete viral replication including CCC DNA amplification occurred in these proliferating cells. Addition of sodium butyrate or aphidicolin reversibly blocked cells in the G1 phase and diminished CCC DNA synthesis, which was restored after drug withdrawal, concomitantly with the entry of cells into S phase. Cell cycle progression of fetal hepatocytes can be triggered by stimulation with epidermal growth factor (EGF), hepatocyte growth factor (HGF), and tumor growth factor alpha (TGF-alpha). CCC DNA synthesis increased with progression to the S phase induced by EGF, HGF, and TGF-alpha alone or in combination. By contrast, tumor growth factor beta (TGF-beta) alone or in combination with EGF inhibited cell proliferation and viral DNA synthesis. By double labeling, viral nucleocapsids were found predominantly in bromodeoxyuridine-positive hepatocytes, indicating that high viral replication occurs preferentially in proliferating hepatocytes. CCC DNA was also detected mainly in cells in the S and G2/M phases separated from cells in the G1 phase by cell sorting. Taken together, these results show that hepatocyte proliferation may positively regulate the initial amplification of CCC DNA of avian hepadnaviruses, and may explain why mitosis is not necessarily associated with loss of CCC DNA.

A new concept for intraoperative matching of 3D ultrasound and CT.

Matching of ultrasound images with CT or MRI scans is an awkward and unsatisfactory task when using conventional methods. Wide ranging differences in modality of ultrasound and CT/MRI require new techniques to be explored for successful alignment. Ultrasound images characteristically show comparable high noise ratio due to scattering inside the region of interest and the surrounding area. Additionally, shadowing and tissue dependent echo response time produce geometric artifacts. These image distortions are sophisticated to recover. Though image quality and geometric relationship are poor, ultrasound images show the potential for fast, low-cost, non-invasive and flexible image acquisition, predestinated for intraoperative application. The fusion of intraoperative ultrasound and preoperatively acquired CT/MRI images provides both, geometric invariance and flexible fast image acquisition, merging in a powerful tool for augmented three dimensional reality. In this paper we describe a completely new concept for alignment with abstaining from direct rigid or elastic matching of ultrasound to CT/MRI. Instead of placing those images in direct relationship, our approach involves a simulation of ultrasound wave behavior in order to predict B-mode images.

Behavioral intervention to reduce child and parent distress during venipuncture.

This study investigated a behavioral intervention incorporating parent coaching, attentional distraction, and positive reinforcement to control child distress during invasive cancer treatment. Children (N = 23) requiring physical restraint to complete venipuncture were alternately assigned to either a behavioral intervention or an attention control condition. Child distress behaviors were recorded, and self-reports of parent, child, and nurse distress were obtained. Parent and nurse also rated child distress. Results of planned comparisons indicate that observed child distress, parent-rated child distress, and parent ratings of his/her own distress were significantly reduced by behavioral intervention and were maintained across the course of three intervention trials. The use of physical restraint to manage child behavior was also significantly reduced. Child self-reported pain and nurse ratings of child distress were not significantly affected.

Analysis of child and parent behavior during painful medical procedures.

Examined (a) the impact of demographic, medical, and psychological factors on overall child distress during an invasive medical procedure required for pediatric cancer treatment and (b) the relationship of individual parent behaviors to child distress across phases of the procedure. Seventy 3- to 10-year-old pediatric cancer patients receiving outpatient venipuncture and their parents participated. Overall distress was greater in younger children who had fewer previous venipunctures and poorer venous access and whose parents rated them prior to the procedure as less likely to be cooperative. Providing explanations regarding the procedure was the parent behavior most clearly associated with child distress. The impact of parent explanation depended on when the explanation was given and on the child's level of distress at the time.