Polarized two-photon photoselection in EGFP: Theory and experiment

In this work, we present a complete theoretical description of the excited state order created by two-photon photoselection from an isotropic ground state; this encompasses both the conventionally measured quadrupolar (K = 2) and the "hidden" degree of hexadecapolar (K = 4) transition dipole alignment, their dependence on the two-photon transition tensor and emission transition dipole moment orientation. Linearly and circularly polarized two-photon absorption (TPA) and time-resolved single- and two-photon fluorescence anisotropy measurements are used to determine the structure of the transition tensor in the deprotonated form of enhanced green fluorescent protein. For excitation wavelengths between 800 nm and 900 nm, TPA is best described by a single element, almost completely diagonal, two-dimensional (planar) transition tensor whose principal axis is collinear to that of the single-photon S₀ → S₁ transition moment. These observations are in accordance with assignments of the near-infrared two-photon absorption band in fluorescent proteins to a vibronically enhanced S₀ → S₁ transition.

Right ventricular myocardial responses to progressive exercise in young adult males

Recent attention has been focused on possible unique features of the right ventricular response to exercise. This study investigated a) the responses of right ventricular cardiac dynamics and myocardial function to a standard bout of progressive cycle exercise in healthy young males, and b) the effect of level of aerobic fitness on these responses. 14 athletically-trained males (20.4±1.5 years) and 11 normally-active males (21.1±1.3 years) underwent a progressive upright cycle test to exhaustion with measurement of gas exchange variables and assessment of right ventricular stroke volume, systolic and diastolic myocardial velocities, and tricuspid inflow velocities by standard Doppler echocardiographic techniques at rest, submaximal and peak exercise. Stroke volume rose initially by approximately 27% in each group, followed by stable values to exhaustion. Values of maximal stroke index and maximal oxygen uptake were significantly greater in the trained group than the normally-active males (62±10 ml m(-2), 54.3±4.0 ml kg(-1) min(-1); 49±7 ml m(-2), 40.3±5.6 ml kg(-1) min(-1), respectively). No significant differences were observed in increases in systolic or diastolic myocardial velocities, peak pulmonary outflow velocity, systolic ejection rate, or tricuspid inflow velocity between the 2 groups. The magnitude of change of these variables was similar to those previously described for left ventricular responses to similar exercise. This study revealed no unique features of right ventricular functional responses to an acute exercise challenge in young males.

Raymond L. Martin

No Abstract Available.

An approach to treating a patient with a HeartMate II™ left ventricularassist device in a multiplace hyperbaric chamber: a case report

INTRODUCTION

Left-ventricular assist devices (LVAD) are becoming a common therapy for end-stage heart failure. These devicesare not tested for pressurization in a hyperbaricchamber by the manufacturer. In this article, we present an approach to modify the power supply in order to safely treat a patient with an LVAD.

MATERIALS AND METHODS

Our patient had a HeartMateII™ LVAD and presented for hyperbaric oxygen treatments for severe radiation cystitis. In order to modify this patient's equipment to be compliant with NFPA6 safety standards we made several modifications. In brief, this included eliminating the usage of lithium-ion batteries, modifying the cord to be compatible with Fink chamber outlets, and enclosing the power module in a nitrogen purge. We then used a mock circulatory system to test our modifications and make sure the LVAD continued to have appropriate flow rates. We then conducted training for staff and developed a disaster plan should the LVAD fail at any point.

RESULTS

Once we felt comfortable with the modifications and had a plan developed should any problems arise, we then proceeded to treat our patient in the hyperbaric chamber. He successfully underwent 44 hyperbaric treatments for radiation cystitis without complications.

CONCLUSION

This case is the second reported patient in the literature with an LVAD that was successfully treated in a multiplace hyperbaric chamber. As LVADs become increasingly popular to manage heart failure, more patients with these devices will present for hyperbaric treatments. With a few modifications, an LVAD patient can be safely and successfully treated in a hyperbaric chamber.

Outcomes at 1 year for the first 200 patients fitted with GyneFix at Margaret Pyke Centre

The first 200 women to be fitted with GyneFix at the Margaret Pyke Centre, a National Health Service contraception clinic situated in central London, have been followed up at 1 year after insertion. Removals, expulsions and accidental pregnancies in that first year are recorded. Of the cohort, 80% had a known outcome at 12 months. There was one perforation with the inserter tube, leaving 199 women fitted with GyneFix who contributed 2033 woman-months of follow-up time. We recorded 22 early removals, of which 16 were for heavy or irregular bleeding and/or pain, three were because the women wished to conceive and three for other reasons. In addition there were 16 expulsions at intervals ranging from 1 day to 12 months after insertion. Four of the expulsions were unnoticed by the subjects (they were revealed by amenorrhea of pregnancy in two subjects and lost threads in the other two). There were no pregnancies with the GyneFix in situ. The expulsion rate of 8.4% (confidence interval (CI) 5.2-13.4%) and removal rate for bleeding and/or pain of 9.0% (CI 5.6-14.3%) at 12 months recorded in this cohort fall within acceptable ranges for framed intrauterine devices in a population with a large percentage of nulliparous women. However, they are perhaps not as good as had been anticipated for this revolutionary new intrauterine implant. Possible reasons for this are explored.