Effect of two-boson exchange on parity-violating e-p scattering.

We compute the corrections from two-photon and gamma-Z exchange in parity-violating elastic electron-proton scattering, used to extract the strange form factors of the proton. We use a hadronic formalism that successfully reconciled the earlier discrepancy in the proton's electron to magnetic form factor ratio, suitably extended to the weak sector. Implementing realistic electroweak form factors, we find effects of the order 2%-3% at Q(2) less, similar0.1 GeV2, which are largest at backward angles and have a strong Q2 dependence at low Q2. Two-boson contributions to the weak axial current are found to be enhanced at low Q2 and for forward angles. We provide corrections at kinematics relevant for recent and upcoming parity-violating experiments.

Delta resonance contribution to two-photon exchange in electron-proton scattering.

We calculate the effects on the elastic electron-proton scattering cross section of the two-photon exchange contribution with an intermediate Delta resonance. The Delta two-photon exchange contribution is found to be smaller in magnitude than the previously evaluated nucleon contribution, with an opposite sign at backward scattering angles. The sum of the nucleon and Delta two-photon exchange corrections has an angular dependence compatible with both the polarization-transfer and the Rosenbluth methods of measuring the nucleon electromagnetic form factors.

Two-photon exchange and elastic electron-proton scattering.

Two-photon exchange contributions to elastic electron-proton scattering cross sections are evaluated in a simple hadronic model including the finite size of the proton. The corrections are found to be small in magnitude, but with a strong angular dependence at fixed Q2. This is significant for the Rosenbluth technique for determining the ratio of the electric and magnetic form factors of the proton at high Q2, and partly reconciles the apparent discrepancy with the results of the polarization transfer technique.

Relativistic effects and two-body currents in (H)((-->)e(')p)n using out-of-plane detection.

Measurements of the (2)H((-->)e,e(')p)n reaction were performed with the out-of-plane magnetic spectrometers (OOPS) at the MIT-Bates Linear Accelerator. The longitudinal-transverse, f(LT) and f(')(LT), and the transverse-transverse, f(TT), interference responses at a missing momentum of 210 MeV/c were simultaneously extracted in the dip region at Q2 = 0.15 (GeV/c)(2). In comparison to models of deuteron electrodisintegration, the data clearly reveal strong effects of relativity and final-state interactions and the importance of two-body meson-exchange currents and isobar configurations. We demonstrate that such effects can be disentangled by extracting these responses using the novel out-of-plane technique.

Treatment of intermittent claudication with pentoxifylline and cilostazol.

The pathophysiology of intermittent claudication (IC) and the role of pentoxifylline and cilostazol for treating IC are discussed. IC, a result of inadequate blood flow to the musculature, is the primary symptom of occlusive peripheral vascular disease (PVD). Patients with IC often have a decreased quality of life because of mobility limitations. PVD is a sign of generalized atherosclerosis and increases the risk of cardiac morbidity and mortality. Smoking, hypertension, diabetes mellitus, and increasing age may hasten the progression of PVD. Strategies for treating IC are aimed at improving symptoms and reducing the progression of atherosclerosis and include risk-factor modification, exercise, and antiplatelet therapy. Cilostazol and pentoxifylline are the only two drugs with FDA-approved labeling for use in treating IC. Both drugs have been shown to increase pain-free walking time and total distance walked, although there is some conflicting evidence for pentoxifylline. Cilostazol and pentoxi-fylline are fairly well tolerated; the most common adverse effects involve the gastrointestinal tract and central nervous system. Inhibitors of cytochrome P-450 isoenzymes 3A4 and 2C19 should be used cautiously in patients taking cilostazol, and this drug is contraindicated in patients with congestive heart failure. Cilostazol is more costly than pentoxifylline. Initiation of therapy with either pentoxifylline or cilostazol may be reasonable if risk-factor modifications, lifestyle changes, and antiplatelet therapy are not effective. The mainstays of therapy for IC are risk-factor modification, exercise, and antiplatelet therapy. If these prove inadequate, treatment with pentoxifylline or cilostazol may be reasonable.

Transdermal nitroglycerin for the prevention of intravenous infusion failure due to phlebitis and extravasation.

OBJECTIVE: To evaluate the clinical use of transdermal nitroglycerin for the prevention of intravenous infusion failures due to phlebitis or extravasation. DATA SOURCES: Clinical literature was accessed through a MEDLINE search (1966-May 2000). Key search terms included nitroglycerin, transdermal, phlebitis, extravasation, intravenous, and infusion. DATA SYNTHESIS: Common and serious consequences of intravenous therapy include the occurrence of postinfusion phlebitis and failure to maintain intravenous therapy due to intravenous fluid extravasation. Transdermal application of nitroglycerin has been evaluated as a treatment and preventive method for intravenous infusion failures related to phlebitis or extravasation. An evaluation of studies focusing on transdermal nitroglycerin in the prevention of infusion failures due to phlebitis or extravasation was conducted. CONCLUSIONS: Use of transdermal nitroglycerin as a prophylactic measure for intravenous infusion failures is a therapeutic option for patients requiring long-term intravenous therapy (i.e., > 50 h).