Neutralization of diverse HIV-1 strains by monoclonal antibodies raised against a gp41 synthetic peptide

Three IgM monoclonal antibodies raised against synthetic peptide analogs of a hydrophilic region of the gp41 transmembrane env protein of HIV-1 neutralize different HIV-1 isolates but not HIV-2 isolates, as determined by HIV titration and by syncytial inhibition assays. VSV (HIV-1) pseudotypes, however, were not neutralized, indicating that gp41 was not accessible to these antibodies on the pseudotype particles. The antibodies affect early steps in adsorption and penetration of HIV-1.     

A new murine model of coronary artery thrombosis and role of interleukin-8 in the development of coronary thrombosis

Occlusive vascular disease most often results from thrombosis superimposed on atherosclerotic plaque. In the case of an acute coronary syndrome including an acute myocardium infarction or an unstable angina pectoris thrombus in coronary artery takes significant part as known. There are few reports about animal models of acute coronary artery thrombi, because of the difficulties of operative significance. We have succeeded in making thrombus at murine coronary arteries with ferric chloride. Slight or moderate IL-8 expressions were found in the endothelial cells in the thrombus formed vessel analyzed by immunohistochemistry. The interleukin-8 (IL-8) receptor knockout mice formed the slight thrombus in coronary arteries treated with ferric chloride. We propose a role for IL-8 in the pathogenesis of acute coronary artery thrombi. This hypothesis lends itself to testing using interventions to influence IL-8 secretion and actions in the early phase of coronary thrombotic formation.     

Human cardiac myosin heavy chain gene mapped within chromosome region 14q11.2----q13

Our previous report demonstrated that two human cardiac alpha- and beta-myosin heavy-chains (MHCs) which correspond to MYH6 and MYH7 respectively, according to Human Gene Mapping nomenclature, were mapped to human chromosome 14 and that human cardiac and skeletal MHC genes do not cosegregate. For further analysis, the regional mapping method was used. DNA from 4 human deletion and 3 human duplication cell lines were prepared for southern blotting, hybridized with human cardiac alpha- and beta-MHC DNA probes, and the hybridization intensity relative to 46,XX or 46,XY DNA was estimated. The results showed that two human cardiac MHC genes segregated with the 14cen----q13 region of the long arm of human chromosome 14. In situ hybridization of 3H-labeled human cardiac alpha-MHC probe to normal human metaphase chromosome independently confirmed this result.     

Changes in properties of the medial gastrocnemius motor units in aging rats

1. The properties of motor units were investigated in the medial gastrocnemius (MG) of old rats [27.5 +/- 1.6 (SD) mo old, n = 18]. Individual motor units were functionally isolated by ventral root fiber splitting and grading stimulus intensity. The muscle-unit portion of the motor unit was identified by the glycogen depletion method. The physiological properties of 77 motor units in 6 animals and the histological results of 7 slow-twitch (type S) muscle units were compared with data from motor units in the same muscle of middle-aged rats (12.8 +/- 1.6 mo old, n = 33). 2. The motor units were classified into four types of categories [FF (fast-twitch motor units with a fatigue index less than or equal to 0.5), FI (fast-twitch motor units with a fatigue index greater than 0.5 but less than 0.75), FR (fast-twitch motor units with a fatigue index greater than or equal to 0.75), S (slow-twitch motor units with a fatigue index greater than 0.75)] using the same criteria (i.e., presence or absence of the "sag" property and fatigability) used for middle-aged rats. No significant difference in the relative distributions of these unit types was detected, although the MG muscle in old rats exhibited a relatively high proportion of type S units and fewer type FR units. 3. The mean tetanic tensions for type FF + FI and FR units were significantly smaller than those in the middle-aged rats. On the other hand, type S motor units produced more tension than in the middle-aged rats. 4. The conduction velocity of motor axons was considerably slower in any unit type of old motor units, and the most marked change was found in type FR units. 5. The general morphological features of the old rat MG were fiber-type grouping, disseminated atrophic or angulated fibers, a decrease in the total number of muscle fibers, and an increase in the number of type I muscle fibers. The major distribution patterns of fibers of different types were the same as those in the middle-aged MG. 6. Seven type S units that produced large tetanic tension were depleted of glycogen in the muscle-unit portions. These units had a large innervation ratio compared with those in the middle-aged rats, whereas the mean cross-sectional area of muscle fibers and the calculated specific tension remained unaltered.(ABSTRACT TRUNCATED AT 400 WORDS)     

Evaluation of cytosolic aminopeptidase in human sera. Evaluation in hepatic disorders

Employing the quantitative electrophoretic separation of cytosolic "LAP" activity (EC. 3.4.11.1), the authors investigated the clinical significances of cytosolic and total "LAP" activities in the sera of patients with several different hepatic disorders and elucidated the previously confusing results of aminopeptidase measurements in clinical laboratories. The dominant aminopeptidases measured in human sera by L-leucinamide as substrate are both cytosolic "LAP" and microsomal aminopeptidase (EC. 3.4.11.2). Total "LAP" activity means the sum of these two aminopeptidases. Different substrate specificities are observed in these two enzymes located in other subcellular fractions and different increasing rates of these enzymes are observed in various hepatic diseases. In cases of acute hepatic cell damage, cytosolic "LAP" accounts for a large percentage of total "LAP" of a patient's serum. On the other hand, in cases of elevation of hepatobiliary enzymes, microsomal aminopeptidase constitutes a large part of total "LAP" activity, and the ratio between cytosolic and total "LAP" activity is very low.     

Picoliter‐Droplet Digital Polymerase Chain Reaction‐Based Analysis of Cell‐Free Plasma DNA to Assess EGFR Mutations in Lung Adenocarcinoma That Confer Resistance to Tyrosine‐Kinase Inhibitors

Purpose.

The objective of this study was to evaluate the utility of analyzing cell-free plasma DNA (cfDNA) by picoliter-droplet digital polymerase chain reaction (ddPCR) to detect EGFR mutations that confer resistance to tyrosine-kinase inhibitors (TKIs) used for treatment of lung adenocarcinoma (LADC).

Experimental design.

Thirty-five LADC patients who received epidermal growth factor receptor (EGFR)-TKI therapy, including ten who received tumor rebiopsy after development of resistance, were subjected to picoliter-ddPCR-cfDNA analysis to determine the fraction of cfDNA with TKI-sensitive (L858R and inflame exon 19 deletions) and -resistant (i.e., T790M) mutations, as well as their concordance with mutation status in rebiopsied tumor tissues.

Results.

cfDNA samples from 15 (94%) of 16 patients who acquired resistance were positive for TKI-sensitive mutations. Also, 7 (44%) were positive for the T790M mutation, with fractions of T790M (+) cfDNA ranging from 7.4% to 97%. T790M positivity in cfDNA was consistent in eight of ten patients for whom rebiopsied tumor tissues were analyzed, whereas the remaining cases were negative in cfDNA and positive in rebiopsied tumors. Prior to EGFR-TKI therapy, cfDNAs from 9 (38%) and 0 of 24 patients were positive for TKI-sensitive and T790M mutations, respectively. Next-generation sequencing of cfDNA from one patient who exhibited innate resistance to TKI despite a high fraction of TKI-sensitive mutations and the absence of the T790M mutation in his cfDNA revealed the presence of the L747P mutation, a known driver of TKI resistance.

Conclusion.

Picoliter-ddPCR examination of cfDNA, supported by next-generation sequencing analysis, enables noninvasive assessment of EGFR mutations that confer resistance to TKIs.

Implications for Practice:

Noninvasive monitoring of the predominance of tumors harboring the secondary T790M mutation in the activating mutation in EGFR gene is necessary for precise and effective treatment of lung adenocarcinoma. Because cells harboring the T790M mutation are resistant to epidermal growth factor receptor-tyrosine-kinase inhibitors (TKIs), the predominance of tumor cells harboring the T790M mutations influences the choice of whether to use conventional or next-generation TKIs. Digital polymerase chain reaction-based examination of cfDNA is a promising method; however, its feasibility, including its consistency with examination of rebiopsied tumor tissue, has not been fully proven. Here, picoliter-droplet digital polymerase chain reaction technology is presented as a candidate method for testing cfDNA and assessing the predominance of T790M-mutant tumors.     

Modified two‐dimensional response as surrogate marker of overall survival in patients with metastatic colorectal cancer

The identification of surrogate markers for long‐term outcomes in patients with metastatic colorectal cancer (mCRC) may help in designing treatment regimens. The aim of this study was to assess whether two‐dimensional response (2‐DR) can serve as a new surrogate marker for overall survival (OS) in patients with mCRC. The study group consisted of 99 patients with mCRC from two independent cohorts who were treated with oxaliplatin‐based chemotherapy plus bevacizumab. Two‐dimensional response was defined as an area enclosed by coordinate points, including early tumor shrinkage at 8 weeks, depth of response at nadir, and 20% increase over nadir at progression. Each variable was weighted by its contribution rate to OS. The model was developed and internally validated in the learning cohort, and the performance of this model was externally verified in the validation cohort. Spearman correlation coefficients for 2‐DR and OS in the learning and validation cohorts were 0.593 and 0.661, respectively. The C‐indexes in predicting OS were 0.724 (95% confidence interval, 0.623–0.815) in the learning cohort and 0.762 (95% confidence interval, 0.651–0.873) in the validation cohort. Overall survival was significantly longer in patients with high 2‐DR values than in patients with low 2‐DR values in both the learning (37.0 vs. 24.1 months, P < 0.001) and validation (41.2 vs. 20.4 months, P < 0.001) cohorts. In contrast, differences in early tumor shrinkage and depth of response were not statistically significant. Multivariate analyses showed that 2‐DR was an independent prognostic factor for OS.