Assessment of myocardial perfusion by harmonic power Doppler imaging at rest and during adenosine stress: comparison with (99m)Tc-sestamibi SPECT imaging.

BACKGROUND: Harmonic power Doppler imaging (HPDI) is a novel technique for assessing myocardial perfusion by contrast echocardiography in humans. The purpose of this study was to compare myocardial perfusion by HPDI with that obtained by (99m)Tc-sestamibi single photon emission computed tomography (SPECT) during rest and pharmacological stress. METHODS AND RESULTS: HPDI was performed on 123 patients who were referred for SPECT imaging for known or suspected coronary artery disease. Images were obtained at baseline and during adenosine infusion (0.14 mg. kg(-)(1). min(-)(1)x6 minutes) in 3 apical views. Myocardial perfusion by HPDI was graded for each coronary territory as absent, patchy, or full. The persistence of absent or patchy myocardial perfusion by HPDI between rest and adenosine was interpreted as a fixed defect, whereas any decrease in perfusion grade was interpreted as a reversible defect. Overall concordance between HPDI and SPECT was 83 (81%) of 103 for normal versus abnormal perfusion. Agreement between the 2 methods for each of the 3 coronary territories was 81% (kappa=0.57) for the left anterior descending artery, 76% (kappa=0.52) for the right coronary artery, and 72% (kappa=0.40) for the left circumflex artery. Discrepancies between the 2 techniques were most notable in the circumflex territory, where fixed defects were observed in 33% by HPDI but in only 14% by SPECT (chi(2)=15.8, P=0.0001). CONCLUSIONS: This study demonstrates that HPDI can reliably detect myocardial perfusion during pharmacological stress, although there was a significantly higher number of falsely abnormal results in the circumflex territory.

Selection and preliminary characterization of acyclovir-resistant mutants of varicella zoster virus.

A series of acyclovir-resistant mutants of varicella zoster virus (VZV) were selected in vitro by serial passage of VZV-infected human fibroblasts in increasing drug concentrations, or by continuous exposure of cultures infected at high multiplicity to 100 microM acyclovir. The in vitro susceptibility of these mutants to several antiherpetic agents was measured by the plaque-reduction assay. The capacity of extracts of cells infected with these mutants to phosphorylate acyclovir was examined and compared with that of their acyclovir-sensitive parent strains. Based on these studies, VZV could be shown to acquire resistance to acyclovir through diminished acyclovir phosphorylation. This was presumable due to loss of viral specific thymidine kinase (TK) function. Two acyclovir-resistant mutants remained TK competent but demonstrated phenotypic changes in sensitivity to antiviral agents known to act at the herpes simplex virus (HSV)-specific DNA polymerase level. These results suggest that the resistance of VZV to acyclovir results from qualitative or quantitative alterations in the virus-specified TK or DNA polymerase.

The validity of the MSI-BPD among inpatient adolescents.

Although the McLean Screening Instrument for Borderline Personality Disorder (MSI-BPD) has shown validity in adult samples, only one study has explored its validity in adolescents and, to our knowledge, the measure has not been validated with inpatient adolescents. The aim of the current study was to evaluate the reliability, and convergent and criterion validity, of the MSI-BPD in an effort to establish the clinical utility of the MSI-PBD as a screening measure for BPD in inpatient adolescents. A total of 121 adolescents from an acute care inpatient unit were recruited for the study. Convergent validity was examined with established measures of BPD in adolescents, including the use of receiver operating characteristics analyses to establish a clinical cutoff score for the MSI-BPD in predicting a diagnosis of BPD. Criterion validity was examined by using this clinical cutoff to investigate group differences in suicidal ideation and Axis I symptoms, known correlates of BPD. Findings demonstrated support for validity of the MSI-BPD when used among inpatient adolescents, and established a clinical cutoff of 5.5. Taken together, this study demonstrates adequate validity for the MSI-BPD, and suggests it is a valuable screening measure for BPD in adolescent inpatients.

Uptake, distribution, and anabolism of acyclovir in herpes simplex virus-infected mice.

The uptake, distribution, and anabolism of the nucleoside analog 9-(2-hydroxyethoxymethyl) guanine (acyclovir) were compared in herpes simplex virus-infected and uninfected mice. Analyses of tissue distribution and the concentration of acyclovir after either a single dose or multiple doses failed to reveal significant differences between drug levels in infected and uninfected animals. Extracts of tissues from [8-14C] acyclovir-treated animals were examined by high-performance liquid chromatography to detect the presence of any phosphorylated forms of the drug. The sensitivity of this method did not allow a reproducible demonstration of acyclovir anabolism in herpes simplex virus-infected tissues owing to the low numbers of infected cells per organ.

A 3-month comparison of 1% and 2% carteolol and 0.5% timolol in open-angle glaucoma.

Carteolol, a nonselective beta-adrenergic antagonist with intrinsic sympathomimetic activity, was compared in 1% and 2% topical solutions with 0.5% timolol in 105 patients with primary open-angle glaucoma. In this double-masked, randomized 3-month trial, all three preparations significantly lowered intraocular pressure throughout the study, with no significant differences being observed. There were also no significant differences among the three preparations with regard to ocular or systemic adverse reactions, including heart rate and blood pressure.