Citations

ABSTRACT The measles virus (MV) P gene codes for three proteins: P, an essential polymerase cofactor, and V and C, which have multiple functions but are not strictly required for viral propagation in cultured cells. V shares the amino-terminal domain with P but has a zinc-binding carboxyl-terminal domain, whereas C is translated from an overlapping reading frame. During replication, the P protein binds incoming monomeric nucleocapsid (N) proteins with its amino-terminal domain and positions them for assembly into the nascent ribonucleocapsid. The P protein amino-terminal domain is natively unfolded; to probe its conformational flexibility, we fused it to the green fluorescent protein (GFP), thereby also silencing C protein expression. A recombinant virus (MV-GFP/P) expressing hybrid GFP/P and GFP/V proteins in place of standard P and V proteins and not expressing the C protein was rescued and produced normal ratios of mono-, bi-, and tricistronic RNAs, but its replication was slower than that of the parental virus. Thus, the P protein retained nearly intact polymerase cofactor function, even with a large domain added to its amino terminus. Having noted that titers of cell-associated and especially released MV-GFP/P were reduced and knowing that the C protein of the related Sendai virus has particle assembly and infectivity factor functions, we produced an MV-GFP/P derivative expressing C. Intracellular titers of this virus were almost completely restored, and those of released virus were partially restored. Thus, the MV C protein is an infectivity factor.

Cystic fibrosis (CF) is a childhood hereditary disease in which the most common mutant form of the CF transmembrane conductance regulator (CFTR) ΔF508 fails to exit the endoplasmic reticulum (ER). Export of wild-type CFTR from the ER requires the coat complex II (COPII) machinery, as it is sensitive to Sar1 mutants that disrupt normal coat assembly and disassembly. In contrast, COPII is not used to deliver CFTR to ER-associated degradation. We find that exit of wild-type CFTR from the ER is blocked by mutation of a consensus di-acidic ER exit motif present in the first nucleotide binding domain. Mutation of the code disrupts interaction with the COPII coat selection complex Sec23/Sec24. We propose that the di-acidic exit code plays a key role in linking CFTR to the COPII coat machinery and is the primary defect responsible for CF in ΔF508-expressing patients.

The inverse problem of determining the size, shape and orientation of a submerged object using the scattered field data is studied. Based on the physical optics approximate, the profile function of the object is found directly proportional to its ramp response that is the second integral of the impulse response. Through analyzing the feature of the ramp response in different computed frequency ranges, it is found that the low-frequency data are essential to the shape of the underwater object while the high-frequency data are very important to the size of the object. Therefore, when employing the high-frequency data to compute the ramp response, the edge of the object can only be highlighted in the illuminated region at certain aspect. Based on this finding, a new method is developed to estimate the size of underwater objects. The present method uses different frequency ranges to determine different parameters of the underwater objects so as to achieve the best accuracy. A number of examples are presented to demonstrate the effectiveness of the present method in using the ramp response technique to identify the size of both rigid and elastic bodies.

Background— The incidence, determinants, and outcome of postoperative atrial fibrillation (AF) after surgery for mitral regurgitation (MR) are poorly defined but may have important implications for timing of mitral valve surgery. Methods and Results— In 762 patients in sinus rhythm with no AF history undergoing MR surgical correction, we examined the rates and prognostic implications of postoperative AF for early AF (within 2 weeks postoperatively) and late AF (>2 weeks after surgery). During postoperative follow-up, 180 patients (24%) experienced new AF (early AF in 136 and late AF in 111). Isolated early AF without recurrence was observed in 69 patients characterized by high angina class and lower left ventricular ejection fraction but no significant left atrial (LA) enlargement. However, overall early AF predicted late AF: 62±5% of patients with early AF had late AF at 10 years compared with 9±1% of patients without early AF ( P <0.0001). Large LA size strongly and independently predicted early AF ( P =0.01) and late AF ( P =0.003). For late AF, the predictive value of an enlarged LA was cumulative to that of early AF. Postoperative AF was associated with an increased subsequently higher risk of stroke or congestive heart failure (adjusted risk ratio=1.46 [1.04 to 2.05], P =0.03). Conclusions— Postoperative AF is common after surgical correction of MR in patients with no prior history of AF and is associated with increased subsequent morbidity. LA enlargement is independently predictive of postoperative AF and as such, should be integrated into the clinical decision-making process in patients with MR.

Abstract Learning Objectives After completing this course, the reader will be able to: Describe the single-agent activity of carboplatin for metastatic breast cancer. Discuss the results of phase II trials of taxanes with platinum agents for breast cancer. Explain the hypothesis for the preclinical interaction between trastuzumab and platinum agents. Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com Background. Anthracycline-based regimens have a limited role in patients with metastatic breast cancer due to cumulative cardiotoxicity and their common use in adjuvant chemotherapy. New nonanthracycline regimens are, therefore, needed for metastatic disease. Single-agent carboplatin is active in patients with previously untreated metastatic breast cancer, producing response rates of 20%–35%. Preclinical studies have demonstrated synergistic antitumor efficacy of carboplatin and trastuzumab in HER2+ models. Methods. Phase II and III clinical trial data of combination therapy with carboplatin (Paraplatin®; Bristol-Myers Squibb; Princeton, NJ), a taxane, and/or trastuzumab (Herceptin®; Genentech, Inc.; South San Francisco, CA) in metastatic breast cancer were identified from multiple sources, including: A) clinical trial data published in peer-reviewed journals within the last 5 years; B) preliminary clinical trial data from abstracts recently presented at national meetings; and C) phase III protocols currently evaluating carboplatin-based combination regimens. Results. In several phase II studies, combination carboplatin and paclitaxel (Taxol®; Bristol-Myers Squibb) therapy was active and reasonably well tolerated in the first-line treatment of metastatic breast cancer, producing objective response rates of 53%–62%—substantially higher rates than those seen in other phase II trials of either drug alone. Similar phase II data for carboplatin with docetaxel (Taxotere®; Aventis; Bridgewater, NJ) have been reported, and recent phase III data suggest that adding carboplatin to a paclitaxel/trastuzumab regimen produces superior efficacy than paclitaxel/trastuzumab alone for patients with HER2+ metastatic disease. Drug scheduling plays an important role in the therapeutic ratio of this combination treatment. Conclusions. Incorporation of carboplatin as a standard agent in first-line treatment of metastatic breast cancer has support from several recent studies. Preliminary results of combination carboplatin/taxane therapy with trastuzumab in metastatic disease are encouraging, and other carboplatin combinations are also being investigated in other phase II and III trials in patients selected based on the HER2 status of their cancer. Results are eagerly awaited.

AbstractAlthough useful palliation can often be achieved when external beam irradiation and chemotherapy are used to treat locally advanced gastrointestinal malignancies, local control and long‐term survival are infrequent in view of the limited tolerance of surrounding organs and tissues. In view of dose limitations of external beam irradiation, intraoperative irradiation (IORT) with electrons has been used as a supplement to external treatment in an attempt to improve the therapeutic ratio of local control versus complications. An IORT dose of 10 to 20 Gy has been combined with fractionated external beam doses of 45 to 55 Gy in 1.8 Gy fractions in studies performed in the United States, Japan, Europe, and Scandinavian countries. In this paper the indications for and the results of aggressive combined techniques that include IORT are discussed. Results obtained with external beam techniques alone or with chemotherapy and resection are presented by site to demonstrate the need for higher doses of irradiation. When results from IORT series are compared to standard treatment with regard to disease control and survival, local control appears better with locally advanced colorectal, gastric, and pancreatic cancer; and survival appears better with colorectal ± biliary cancers. With pancreatic cancer, improvements in local control do not translate into increased survival in view of the high incidence of subsequent liver and peritoneal failures. Implications for future strategies in all sites are discussed.

ABSTRACT A collection of 99 staphylococcal isolates associated with prosthetic joint infection and 23 coagulase-negative staphylococci isolated from noninfected arthroplasty-associated specimens were screened in order to determine whether the presence of icaA could be used to distinguish between pathogens and nonpathogens. All Staphylococcus aureus prosthetic joint infection isolates ( n = 55) were icaA positive. A total of 46% (20 out of 44) of coagulase-negative staphylococcal prosthetic joint infection isolates were icaA positive, and 30% (7 out of 23) of arthroplasty-associated non-prosthetic joint infection-associated coagulase-negative staphylococcal isolates were icaA positive ( P = 0.23). Certain coagulase-negative Staphylococcus species appeared more likely to be isolated as either arthroplasty-associated non-prosthetic joint infection-associated isolates (e.g., Staphylococcus warneri and Staphylococcus hominis ) or pathogens (e.g., Staphylococcus lugdunensis ). The presence of icaA in a coagulase-negative staphylococcal isolate associated with an arthroplasty is not a useful diagnostic indicator of pathogenicity.

Hepatic steatosis predisposes the liver to cold ischemia-warm reperfusion (CI/WR) injury by unclear mechanisms. Because hepatic steatosis has recently been associated with a lysosomal pathway of apoptosis, our aim was to determine whether this cell-death pathway contributes to CI/WR injury of steatotic livers. Wild-type and cathepsin B-knockout ( Ctsb −/−) mice were fed the methionine/choline-deficient (MCD) diet for 2 wk to induce hepatic steatosis. Mouse livers were stored in the University of Wisconsin solution for 24 h at 4°C and reperfused for 1 h at 37°C in vitro. Immunofluorescence analysis of the lysosomal enzymes cathepsin B and D showed a punctated intracellular pattern consistent with lysosomal localization in wild-type mice fed a standard diet after CI/WR injury. In contrast, cathepsin B and D fluorescence became diffuse in livers from wild-type mice fed MCD diet after CI/WR, indicating that lysosomal permeabilization had occurred. Hepatocyte apoptosis was rare in both normal and steatotic livers in the absence of CI/WR injury but increased in wild-type mice fed an MCD diet and subjected to CI/WR injury. In contrast, hepatocyte apoptosis and liver damage were reduced in Ctsb −/− and cathepsin B inhibitor-treated mice fed the MCD diet following CI/WR injury. In conclusion, these findings support a prominent role for the lysosomal pathway of apoptosis in steatotic livers following CI/WR injury.