Citations

ABSTRACT The initiation of reverse transcription and nucleocapsid assembly in hepatitis B virus (HBV) depends on the specific recognition of an RNA signal (the packaging signal, ε) on the pregenomic RNA (pgRNA) by the viral reverse transcriptase (RT). RT-ε interaction in the duck hepatitis B virus (DHBV) was recently shown to require the molecular chaperone complex, the heat shock protein 90 (Hsp90). However, the requirement for RT-ε interaction in the human HBV has remained unknown due to the inability to obtain a purified RT protein active in specific ε binding. We now report that Hsp90 is also required for HBV RT-ε interaction. Inhibition of Hsp90 led to diminished HBV pgRNA packaging into nucleocapsids in cells, which depends on RT-ε interaction. Furthermore, using truncated HBV RT proteins purified from bacteria and five purified Hsp90 chaperone factors, we have developed an in vitro RT-ε binding assay. Our results demonstrate that Hsp90, in a dynamic process that was dependent on ATP hydrolysis, facilitated RT-ε interaction in HBV, as in DHBV. Specific ε binding required sequences from both the amino-terminal terminal protein and the carboxy-terminal RT domain. Only the cognate HBV ε, but not the DHBV ε, could bind the HBV RT proteins. Furthermore, the internal bulge, but not the apical loop, of ε was required for RT binding. The establishment of a defined in vitro reconstitution system has now paved the way for future biochemical and structural studies to elucidate the mechanisms of RT-ε interaction and chaperone activation.

Current nursing knowledge has been generated by studies whose designs range from exploratory to experimental. Searching the literature for a study illustrating a particular design can be a perplexing process. This article explains strategies that are useful in identifying research studies according to the designs used in their methods. The suggested search strategies assist in identifying the most relevant search results and can save time. Outcomes of such a search can be instructional about the implementation of a design in its classic form or some variation. They can provide practical illustrations of the advantages and limitations of a design when applied in a particular area of interest.

Background— The primary aim and central hypothesis of the study are that a designated syncope unit in the emergency department improves diagnostic yield and reduces hospital admission for patients with syncope who are at intermediate risk for an adverse cardiovascular outcome. Methods and Results— In this prospective, randomized, single-center study, patients were randomly allocated to 2 treatment arms: syncope unit evaluation and standard care. The 2 groups were compared with χ 2 test for independence of categorical variables. Wilcoxon rank sum test was used for continuous variables. Survival was estimated with the Kaplan-Meier method. One hundred three consecutive patients (53 women; mean age 64±17 years) entered the study. Fifty-one patients were randomized to the syncope unit. For the syncope unit and standard care patients, the presumptive diagnosis was established in 34 (67%) and 5 (10%) patients ( P <0.001), respectively, hospital admission was required for 22 (43%) and 51 (98%) patients ( P <0.001), and total patient-hospital days were reduced from 140 to 64. Actuarial survival was 97% and 90% ( P =0.30), and survival free from recurrent syncope was 88% and 89% ( P =0.72) at 2 years for the syncope unit and standard care groups, respectively. Conclusions— The novel syncope unit designed for this study significantly improved diagnostic yield in the emergency department and reduced hospital admission and total length of hospital stay without affecting recurrent syncope and all-cause mortality among intermediate-risk patients. Observations from the present study provide benchmark data for improving patient care and effectively utilizing healthcare resources.

Uterine dehiscence is the incomplete separation of the myometrium at a uterine scar site, usually from a previous cesarean section. Because membranes remain intact, the prognosis for both mother and fetus is generally good. However, labor contractions may lead to progression and a complete uterine rupture, which can be catastrophic. The combination of abdominal pain, previous cesarean section, and the sonographic finding of ballooning membranes should suggest the diagnosis of uterine dehiscence.

AbstractAs refinement of technetium‐99m 2‐methoxyisobutyl isonitrile‐scintigraphy (MIBI)‐scintigraphy of parathyroid glands has continued since its initial use in 1989, the sensitivity, specificity, and overall accuracy of the technique have improved greatly, approaching 100% for larger, solitary adenomas. Preoperative use of sestamibi scintigraphy has become commonplace and allows surgeons the option of a minimally invasive, or focused approach for their patients with primary hyperparathyroidism. Intraoperative use of the gamma probe based on sestamibi localization has not caught on due to lesser accuracy, cumbersome gamma probes, small doses of radiation exposure for patients and staff, and the greater accuracy and current confidence in intraoperative parathormone (PTH) monitoring. However, with the potential for smaller and more accurate gamma probes that truly assist in localizing abnormal parathyroid glands, the potential for cost reduction by shortening operative times, avoiding expensive PTH assays, and eliminating the need for pathologic analysis, gamma scintigraphy may yet become a viable option for many parathyroid surgeons.