Diffusion and Binding of Radio-Labeled Antibodies in a Tumor

With the decreasing cost of monoclonal antibody production, radioimmunotherapy (RIT) has rapidly emerged as one of the more promising methods of treating cancer cells. RIT makes use of radio-labeled monoclonal antibodies to detect and deliver controlled doses of radiation to malignant cells. The primary advantage of this method is that damage to normal, healthy tissue is minimized. We investigated the use of radio-labeled antibodies as a method of tumor destruction. Our primary interests were the rate of antibody diffusion into the tumor, the antibody binding kinetics, and the overall effectiveness of radioimmunotherapy given the rate of radioactive decay. By modeling the concentration of bound antibody with respect to time, we were able to optimize tumor destruction while minimizing the damage to the surrounding tissue. Our results show that a computer simulation using FIDAP is a time-saving, cost-effective method of obtaining quantitative results about the binding kinetics of antibody to tumor. In addition, we determined that while the binding specificity plays an important role in ensuring proper binding to the tumor, the rate of antibody to antigen complex formation does not affect the treatment and that this process is limited by diffusion. Given this fact, we recommend that low molecular weight antibodies be used because they will typically have higher diffusivities. In an example case of metastatic melanoma, we found that 4.33 mg of 188Re-6D2 complex would destroy the tumor in our model

Simultaneous splicing of multiple DNA fragments in one PCR reaction

BACKGROUND: Rapid and simultaneous splicing of multiple DNA fragments is frequently required in many recombinant DNA projects. However, former overlap extension PCRs, the most common methods for splicing DNA fragments, are not really simultaneous fusing of multiple DNA fragments. RESULTS: We performed an optimized method which allowed simultaneous splicing of multiple DNA fragments in one PCR reaction. Shorter outermost primers were prior mixed with other PCR components at the same time. A sequential thermo cycling program was adopted for overlap extension reaction and amplification of spliced DNA. Annealing temperature was relatively higher in the overlap extension reaction stage than in the fused DNA amplification. Finally we successfully harvested target PCR products deriving from fusion of two to seven DNA fragments after 5–10 cycles for overlap extension reaction and then 30 cycles for fused DNA amplification. CONCLUSIONS: Our method provides more rapid, economical and handy approach to accurately splice multiple DNA fragments. We believe that our simultaneous splicing overlap extension PCR can be used to fuse more than seven DNA fragments as long as the DNA polymerase can match

Characterizing the role of miRNAs within gene regulatory networks using integrative genomics techniques

By integrating genotype information, microRNA transcript abundances and mRNA expression levels, Eric Schadt and colleagues provide insights into the genetic basis of microRNA gene expression and the role of microRNAs within the liver gene-regulatory network

Interfacial Properties of Polyethylene Glycol/Vinyltriethoxysilane (PEG/VTES) Copolymers and their Application to Stain Resistance

In this study, polyethylene glycol (PEG) and vinyltriethoxysilane (VTES) were used in different proportions to produce a series of PEG–VTES copolymers. The copolymer molecular structures were confirmed by FTIR spectroscopy. In addition, their surface activities were evaluated by evaluating the surface tension, contact angle, and foaming properties. The results showed that these surfactants exhibited excellent surface activities and wetting power, as well as low foaming. Consequently, the application of a series of PEG/VTES copolymers can make cotton fabrics stain resistant

Ser-634 and Ser-636 of Kaposi’s Sarcoma-Associated Herpesvirus RTA are Involved in Transactivation and are Potential Cdk9 Phosphorylation Sites

The replication and transcription activator (RTA) of Kaposi’s sarcoma-associated herpesvirus (KSHV), K-RTA, is a lytic switch protein that moderates the reactivation process of KSHV latency. By mass spectrometric analysis of affinity purified K-RTA, we showed that Thr-513 or Thr-514 was the primary in vivo phosphorylation site. Thr-513 and Thr-514 are proximal to the nuclear localization signal (527KKRK530) and were previously hypothesized to be target sites of Ser/Thr kinase hKFC. However, substitutions of Thr with Ala at 513 and 514 had no effect on K-RTA subcellular localization or transactivation activity. By contrast, replacement of Ser with Ala at Ser-634 and Ser-636 located in a Ser/Pro-rich region of K-RTA, designated as S634A/S636A, produced a polypeptide with ∼10 kDa shorter in molecular weight and reduced transactivation in a luciferase reporter assay relative to the wild type. In contrast to prediction, the decrease in molecular weight was not due to lack of phosphorylation because the overall Ser and Thr phosphorylation state in K-RTA and S634A/S636A were similar, excluding that Ser-634 or Ser-636 motif served as docking sites for consecutive phosphorylation. Interestingly, S634A/S636A lost ∼30% immuno-reactivity to MPM2, an antibody specific to pSer/pThr-Pro motif, indicating that 634SPSP637 motif was in vivo phosphorylated. By in vitro kinase assay, we showed that K-RTA is a substrate of CDK9, a Pro-directed Ser/Thr kinase central to transcriptional regulation. Importantly, the capability of K-RTA in associating with endogenous CDK9 was reduced in S634A/S636A, which suggested that Ser-634 and Ser-636 may be involved in CDK9 recruitment. In agreement, S634A/S636A mutant exhibited ∼25% reduction in KSHV lytic cycle reactivation relative to that by the wild type K-RTA. Taken together, our data propose that Ser-634 and Ser-636 of K-RTA are phosphorylated by host transcriptional kinase CDK9 and such a process contributes to a full transcriptional potency of K-RTA

Profiles of Impulsivity in Problematic Internet Users and Cigarette Smokers

Problematic Internet use (PIU) has been gradually recognized as a mental health issue among adolescents and young students. PIU shows many similarities with substance use disorders, but the shared and distinct mechanisms underlying them are unclear. The purpose of the current study was to explore the relationships between impulsive traits and PIU as well as cigarette smoking behaviors among young adults. Two independent samples of university students (N1 = 1281, N2 = 1034, respectively) over 3 years were assessed with multiple measurements of impulsivity, including the Barratt Impulsiveness Scale-11 (BIS-11), the UPPSP Impulsive Behaviors Scale (UPPSP), and the Delay-discounting Test (DDT). Logistic regression models revealed that across the two independent samples, BIS-11 Attentional Impulsiveness was the common trait positively predicting both PIU and cigarette smoking. While BIS-11 Motor Impulsiveness as well as UPPSP Lack of Perseverance, Lack of Premeditation, and Negative Urgency were the typical traits linked to PIU as positive predictors, UPPSP Sensation Seeking was the unique trait linked to cigarette smoking as a positive predictor. These results suggested that specific dimensions of impulsivity might be concurrently implicated in PIU and cigarette smoking among young adults, putatively representing important trait marks for addictive behaviors