Screenomics: A Framework to Capture and Analyze Personal Life Experiences and the Ways that Technology Shapes Them.

Digital experiences capture an increasingly large part of life, making them a preferred, if not required, method to describe and theorize about human behavior. Digital media also shape behavior by enabling people to switch between different content easily, and create unique threads of experiences that pass quickly through numerous information categories. Current methods of recording digital experiences provide only partial reconstructions of digital lives that weave - often within seconds - among multiple applications, locations, functions and media. We describe an end-to-end system for capturing and analyzing the "screenome" of life in media, i.e., the record of individual experiences represented as a sequence of screens that people view and interact with over time. The system includes software that collects screenshots, extracts text and images, and allows searching of a screenshot database. We discuss how the system can be used to elaborate current theories about psychological processing of technology, and suggest new theoretical questions that are enabled by multiple time scale analyses. Capabilities of the system are highlighted with eight research examples that analyze screens from adults who have generated data within the system. We end with a discussion of future uses, limitations, theory and privacy.

Long-Term Outcomes of Patients with Stent Tips Embedded into Internal Carotid Artery Branches during Aneurysm Coiling.

BACKGROUND AND PURPOSE: During stent-assisted coiling of ICA aneurysms, stent tips are sometimes unintentionally embedded into ICA branches. Stent tips can be visualized because they have radiopaque markers. Concerns regarding stent tip misplacement include risks of artery perforation and occlusion. The aim of this study was to evaluate the long-term outcomes of ICA branches with embedded stent tips. MATERIALS AND METHODS: ICA branches with embedded stent tips were identified among 35 patients with unruptured ICA aneurysms treated with stent-assisted coiling between November 2003 and November 2014. Patient clinical and angiographic outcomes associated with the embedded stent tip were analyzed. RESULTS: Most of the 35 studied aneurysms were paraclinoid ICA aneurysms (n = 30). The most commonly involved ICA branch was the posterior communicating artery (26 patients, 74.3%), followed by the anterior choroidal artery (8 patients, 22.9%) and ophthalmic artery (1 patient, 2.9%). During the follow-up period (38.6 ± 17.9 months), no new neurologic deficits developed. Neither hemorrhagic nor thromboembolic events occurred. Angiography was performed during the final follow-up evaluation at a mean of 32.7 ± 18.0 months, and all ICA branches with embedded stent tips showed patent blood flow without severe luminal narrowing. CONCLUSIONS: In our experience, placement of a stent tip into ICA branches during stent-assisted coiling was not associated with any major adverse events.

Hyperopic refractive errors as a prognostic factor in intermittent exotropia surgery.

UNLABELLED: Purpose: To evaluate and compare surgical outcomes with respect to refractive errors in strabismus surgery for the treatment of intermittent exotropia (IXT). METHODS: The medical records of patients with IXT who were treated by one surgeon from January 2005 and June 2011 were reviewed. Three hundred and thirty-three IXT patients were included and divided into three groups according to preoperative refractive error: IXT with hyperopia (group I), IXT with emmetropia (group II), and IXT with myopia (group III). The surgical outcomes with respect to sensory and motor criteria were compared among the three groups. RESULTS: The surgical success rates according to motor criteria and sensory and motor criteria combined were higher in groups I (29 patients) and III (124 patients) than in group II (180 patients) at postoperative 3 and 6 months and at the last follow-up. Stereopsis was significantly better in groups II and III than in group I preoperatively (P=0.002 by one-way analysis of variance test); however, the difference was not significant postoperatively. Twenty patients in group I (69.0%) were prescribed undercorrected hyperopic spectacles postoperatively, while only 22 patients in group III (17.7%) were prescribed spectacles with more myopic power than their refractive errors. CONCLUSION: In the surgical treatment of IXT, hyperopia was not an indicator of poor prognosis. Taking into consideration the age effect, follow-up period after IXT surgery, and stereopsis improvement, hyperopic refractive error is rather a good prognostic factor.

Effects of beta-blockers for congestive heart failure in pediatric and congenital heart disease patients: a meta-analysis of published studies.

AIM: The effects of beta-blockers in pediatric and congenital heart disease (CHD) patients suffering from heart failure are controversial. We performed a meta-analysis to determine whether beta-blockers are effective for heart failure in pediatric and CHD patients. METHODS: We searched for clinical trials focusing on clinical on clinical and ventricular functional/dimensional changes after beta-blocker therapy in PubMed (from its inception to August 2013) and bibliographies of identified studies. Studies investigating any of three beta blockers (carvedilol, bisoprolol, and extended release metoprolol succinate) which are known to be effective in adult patients with heart failure were included. RESULTS: Of the 158 screened, 17 (N.=476) fulfilled the study criteria and were analyzed. Beta-blockers were associated with significant improvements in left ventricular (LV) ejection fraction (EF) (12.47%; 95% CI, 10.36 to 14.61), fraction shortening (5.75%; 95% CI, 4.42 to 7.08), LV end-diastolic dimension (-2.91 mm; 95% CI, -5.46 to -0.36), and LV systolic dimension (-4.03 mm; 95% CI, -6.81 to -1.25). No significant change in the pooled mean difference of the right ventricular (RV) EF (3.50%; P=0.08) was observed. However, the RV EF in the untreated group showed a deteriorating trend (-3%), which was different from the trend in the treatment group. There was a significant reduction in the incidence of clinical worsening (odds ratio, 2.15; 95% CI, 1.27 to 3.66). CONCLUSION: Beta-blocker therapy was associated with a significant improvement of echocardiographic parameters in patients with systemic LV failure. However, the use of beta-blockers did not provide significant benefits in terms of improving the EF in patients with RV failure. Nonetheless, beta-blockers may be effective to prevent the clinical deterioration of pediatric and CHD patients with heart failure.

Epidural naloxone reduces postoperative nausea and vomiting in patients receiving epidural sufentanil for postoperative analgesia.

BACKGROUND: Epidural opioids have excellent analgesic properties, but their side-effects limit their use in patient-controlled epidural analgesia. This study was designed to evaluate the effect of epidural naloxone on the side-effects of sufentanil, focusing on postoperative nausea and vomiting (PONV) in patients undergoing total knee replacement (TKR). METHODS: After obtaining Institutional Review Board approval and informed consent, 50 patients undergoing unilateral TKR were randomly assigned to receive either sufentanil in ropivacaine alone (Group C, n = 25) or the same solution with naloxone (Group N, n = 25) for their postoperative epidural analgesia. Episodes of PONV and five-point-scaled nausea scores were evaluated at 6, 12, and 24 h after epidural analgesia was started. Visual analogue scale (VAS) score for pain and the incidence of sedation, pruritus, hypotension, and respiratory depression were also evaluated at each of three time points. RESULTS: The nausea score in Group N was significantly lower than that in Group C. The VAS pain score at rest and on movement were significantly lower in Group N than in Group C at 24 h. Other opioid-induced side-effects were not significantly different. CONCLUSIONS: Epidural naloxone was effective in reducing PONV induced by epidural sufentanil and additionally enhanced the analgesic effect. Therefore, concomitant infusion of a small dose of epidural naloxone should be considered to reduce PONV, especially in patients at greater risk for PONV.

Thiobarbituric acid reactive substances and volatile compounds in chicken breast meat infused with plant extracts and subjected to electron beam irradiation.

The effect of irradiation on thiobarbituric acid reactive substances (TBARS) and volatile compounds in raw and cooked nonirradiated and irradiated chicken breast meat infused with green tea and grape seed extracts was investigated. Chicken breast meat was vacuum infused with green tea extract (3,000 ppm), grape seed extract (3,000 ppm), or their combination (at a total of 6,000 ppm), irradiated with an electron beam, and stored at 5 degrees C for 12 d. The targeted irradiation dosage was 3.0 kGy and the average absorbed dosage was 3.12 kGy. Values of TBARS and volatile compound contents of raw and cooked chicken meat were determined during the 12-d storage period. Thiobarbituric acid reactive substances values ranged from 15.5 to 71.4 mg of malondialdehyde/kg for nonirradiated raw chicken and 17.3 to 80.1 mg of malondialdehyde/kg for irradiated raw chicken. Values for cooked chicken ranged from 31.4 to 386.2 and 38.4 to 504.1 mg of malondialdehyde/kg for nonirradiated and irradiated chicken, respectively. Irradiation increased TBARS and hexanal values of controls and meat infused with plant extracts. Hexanal had the highest intensity of volatiles followed by pentanal and other volatiles. Cooking the samples significantly (P < 0.05) increased the amounts of TBARS and volatiles. Addition of plant extracts decreased the amount of TBARS as well as hexanal and pentanal values. Although irradiation increases lipid oxidation, infusion of chicken meat with plant extracts could reduce lipid oxidation caused by irradiation.

Expression profiling of radiation-induced genes in radiodermatitis of hairless mice.

BACKGROUND: Radiation induces many cellular events leading to radiodermatitis. OBJECTIVES: The aim of this study was to establish a radiodermatitis model using experimental animals, and to examine the expression profile of radiation-induced genes. METHODS: Hairless mice were irradiated on the dorsal skin; then total RNAs were isolated and microarray hybridizations were performed. RESULTS: Irradiation with a total of 40 Gy (10 Gy day-1 for four consecutive days) provokes radiodermatitis in the hairless mouse. After microarray analysis, 130 genes that showed upregulation by radiation were selected and organized into four different clusters, depending on the time-kinetic pattern. Classification of these genes into several functional categories revealed that various biological processes were globally affected by radiation. These include transcription regulation, signal transduction, cell communication, cell death regulation and metabolism. CONCLUSIONS: These results demonstrate the complexity of the transcriptional profile of the radiation response, providing important clues on which to base further investigations of the molecular events underlying radiodermatitis.

AtBAG6, a novel calmodulin-binding protein, induces programmed cell death in yeast and plants.

Calmodulin (CaM) influences many cellular processes by interacting with various proteins. Here, we isolated AtBAG6, an Arabidopsis CaM-binding protein that contains a central BCL-2-associated athanogene (BAG) domain. In yeast and plants, overexpression of AtBAG6 induced cell death phenotypes consistent with programmed cell death (PCD). Recombinant AtBAG6 had higher affinity for CaM in the absence of free Ca2 + than in its presence. An IQ motif (IQXXXRGXXXR, where X denotes any amino-acid) was required for Ca2 +-independent CaM complex formation and single amino-acid changes within this motif abrogated both AtBAG6-activated CaM-binding and cell death in yeast and plants. A 134-amino-acid stretch, encompassing both the IQ motif and BAG domain, was sufficient to induce cell death. Agents generating oxygen radicals, which are known to be involved in plant PCD, specifically induced the AtBAG6 transcript. Collectively, these results suggest that AtBAG6 is a stress-upregulated CaM-binding protein involved in plant PCD.

Antibodies as drug carriers III: design of oligonucleotides with enhanced binding affinity for immunoglobulin G.

PURPOSE: To understand the structural requirements in designing epitope-bearing oligonucleotides with high antibody-binding affinity. METHODS: Binding affinity (KA) and stoichiometry (n) of dinitrophenyl (DNP)-derivatized model 27-mer oligonucleotides (ODNs), GGG(AAA)7GGG, to monoclonal anti-trinitrophenyl (TNP) antibodies were determined using isothermal titration calorimetry (ITC). Structural variations were made in the ODNs to assess the effects of antigenic valence, epitope density, inter-epitope linker length, and linker flexibility. Binding isotherms were fitted with a single binding-site model to obtain K(A) and n, from which changes in Gibbs free energy (deltaG(0)), entropy (deltaS(0)), and enthalpy (deltaH(0)) were derived. RESULTS: As expected, ligands displaying increased epitope density showed increases in K(A): for example, K(A) for (DNP)2-Cys is 3.3-fold greater than that for DNP-Lys. Introduction of multiple DNP groups via long and flexible linkers to one end of the 27-mer ODN resulted in a bivalent behavior with n value of 1. A bivalent ligand, derivatized at both ends with a long and flexible linker, failed to form an immune complex when hybridized to its antisense strand, presumably due to intercalation of the DNP moiety to the double strand. ODNs derivatized with flexible linkers exhibited a higher K(A) than those with a rigid linker. Ligands with flexible inter-epitope linkers measuring distances of 110, 60, and 40 angstroms yielded 13-, 30-, and 13-fold increases in K(A), respectively. The combination of these factors; namely, bivalence, flexible inter-epitope linkers, and optimal inter-epitope distance, resulted in an overall 66-fold increase in K(A). Thermodynamic analysis of binding indicates that the formation of high-affinity ODN-IgG complexes was a spontaneous and exothermic event, characterized by large negative deltaS degrees, deltaH degrees, and deltaG degrees values. CONCLUSIONS: All four strategies tested during this investigation, namely bivalence, epitope density, inter-epitope linker flexibility, and optimal inter-epitope distance, proved to be useful in improving the binding affinity of DNP-labeled ODNs to anti-TNP IgG. The final ODN design incorporating these strategies will be used in testing the systemic pharmacokinetic advantage gained from complexing such ODNs to IgG.

Inactivation of pathogenic bacteria by cucumber volatiles (E,Z)-2,6-nonadienal and (E)-2-nonenal.

The effects of (E,Z)-2,6-nonadienal (NDE) and (E)-2-nonenal (NE) on Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium were investigated. A suspension of each organism of 6 to 9 log CFU/ml was incubated for 1 h at 37 degrees C in brain heart infusion solution that contained 0 to 500 or 1,000 ppm of NDE or NE. Depending on concentration, exposure to either NDE or NE caused a reduction in CFU of each organism. Treatment with 250 and 500 ppm NDE completely eliminated viable B. cereus and Salmonella Typhimurium cells, respectively. L. monocytogenes was the most resistant to NDE, showing only about a 2-log reduction from exposure to 500 ppm for 1 h. Conversely, this concentration of NDE caused a 5.8-log reduction in E. coli O157:H7 cells. NE was also effective in inactivating organisms listed above. A higher concentration of NE, 1,000 ppm, was required to kill E. coli O157:H7, L. monocytogenes, or Salmonella Typhimurium compared with NDE. In conclusion, both NDE and NE demonstrated an apparent bactericidal activity against these pathogens.

Stable transformation of rice (Oryza sativa L.) via microprojectile bombardment of highly regenerative, green tissues derived from mature seed.

A highly efficient and reproducible transformation system for rice ( Oryza sativa L. cv. Taipei 309) was developed using microprojectile bombardment of highly regenerative, green tissues. These tissues were induced from mature seeds on NB-based medium containing 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP) and high concentrations of cupric sulfate under dim light conditions; germinating shoots and roots were completely removed. Highly regenerative, green tissues were proliferated on the same medium and used as transformation targets. From 431 explants bombarded with transgenes [i.e. a hygromycin phosphotransferase ( hpt) gene plus one of a wheat thioredoxin h ( wtrxh), a barley NADP-thioredoxin reductase ( bntr), a maize Mutator transposable element ( mudrB) or beta-glucuronidase ( uidA; gus) gene], 28 independent transgenic events were obtained after an 8- to 12-week selection period, giving a 6.5% transformation frequency. Of the 28 independent events, 17 (61%) were regenerable. Co-transformation of the second introduced transgene was detected in 81% of the transgenic lines tested. Stable integration and expression of the foreign genes in T(0) plants and T(1) progeny were confirmed by DNA hybridization, western blot analyses and germination tests.

Long-term stability of transgene expression driven by barley endosperm-specific hordein promoters in transgenic barley.

In order to evaluate the long-term stability of transgene expression driven by the B(1)- and D-hordein promoters in transgenic barley ( Hordeum vulgare L., 2 n=2 x=14), we analyzed plants from 15 independent transgenic barley lines [6 for uidA and 9 for sgfp(S65T)] produced via microprojectile bombardment of immature embryos; 4 were diploid and 11 were tetraploid. The expression and inheritance of transgenes were determined by analysis of functional transgene expression, polymerase chain reaction and fluorescence in situ hybridization (FISH). Ability to express transgenes driven by either B(1)- or D-hordein promoter was inherited in T(4) and later generations: T(4) (2 lines), T(5) (8 lines), T(6) (3 lines), T(8) (1 line) and T(9) (1 line). Homozygous transgenic plants were obtained from 12 lines [5 for uidA and 7 for sgfp(S65T)]; the remaining lines are currently being analyzed. The application of the FISH technique for physical mapping of chromosomes was useful for early screening of homozygous plants by examining for presence of the transgene. For example, one line expressing uidA, and shown to have doublet fluorescence signals on a pair of homologous chromosomes was confirmed as a homozygous line by its segregation ratio; additionally this line showed stable inheritance of the transgene to T(9) progeny. The expression of transgenes in most lines (14 out of 15 lines) driven by hordein promoters was stably transmitted to T(4) or later generations, although there was a skewed segregation pattern (1:1) from the T(1) generation onward in the remaining line. In contrast, transgene silencing or transgene loss under the control of the maize ubiquitin promoter was observed in progeny of only 6 out of 15 lines.

AlphaIIbbeta3-mediated outside-in signaling induced by the agonist peptide LSARLAF utilizes ADP and thromboxane A2 receptors to cause alpha-granule secretion by platelets.

The peptide LSARLAF (LSA) causes alphaIIbbeta3-dependent platelet activation that results in alpha-granule secretion and aggregation. LSARLAF-induced, alphaIIbbeta3-mediated outside-in signaling causing alpha-granule secretion and platelet aggregation was studied using washed mouse platelets. ADP receptor antagonists, enzyme inhibitors, normal platelets and platelets from mice that lack either Galphaq or thromboxane (Tx) A2 receptors were used for this investigation. The results demonstrate that LSA-induced alphaIIbbeta3-mediated signaling producing aggregation of washed platelets is mediated through the release of ADP and thromboxane, which cause alpha-granule release by mediating their effects though Galphaq and/or Gi depending on the level of LSA used to activate the platelets. Specifically, alphaIIbbeta3 elicited aggregation of washed platelets in response to a low level of LSA requires signaling through the ADP receptor P2Y1 and Galphaq, and the ADP receptor P2Y12 and Gi as well as TxA2 receptors. However, this aggregation is independent of Galphaq and TxA2 signaling in response to high LSA concentrations, but is dependent on ADP signaling through its receptor P2Y12, and therefore presumably Gi, regardless of the level of LSA used to activate the platelets. PKC function is required for ADP secretion and the subsequent signaling through P2Y12 regardless of the level of LSA used to activate the platelets. The end point of the LSA-induced alphaIIbbeta3-mediated signaling characterized in this study is alpha-granule secretion, which provides the fibrinogen required for aggregation of washed platelets.

Expression of green fluorescent protein and its inheritance in transgenic oat plants generated from shoot meristematic cultures.

The expression of green fluorescent protein (GFP) and its inheritance were studied in transgenic oat ( Avena sativa L.) plants transformed with a synthetic green fluorescent protein gene [sgfp(S65T)] driven by a rice actin promoter. In vitro shoot meristematic cultures (SMCs) induced from shoot apices of germinating mature seeds of a commercial oat cultivar, Garry, were used as a transformation target. Proliferating SMCs were bombarded with a mixture of plasmids containing the sgfp(S65T) gene and one of three selectable marker genes, phosphinothricin acetyltransferase (bar), hygromycin phosphotransferase (hpt) and neomycin phosphotransferase (nptII). Cultures were selected with bialaphos, hygromycin B and geneticin (G418), respectively, to identify transgenic tissues. From 289 individual explants bombarded with the sgfp(S65T) gene and one of the three selectable marker genes, 23 independent transgenic events were obtained, giving a 8.0% transformation frequency. All 23 transgenic events were regenerable, and 64% produced fertile plants. Strong GFP expression driven by the rice actin promoter was observed in a variety of tissues of the T(0) plants and their progeny in 13 out of 23 independent transgenic lines. Stable GFP expression was observed in T(2) progeny from five independent GFP-expressing lines tested, and homozygous plants from two lines were obtained. Transgene silencing was observed in T(0) plants and their progeny of some transgenic lines.

Use of fluorescence in situ hybridization for gross mapping of transgenes and screening for homozygous plants in transgenic barley ( Hordeum vulgare L.).

Introduced transgenes, uidA, sgfp (S65T) and/or bar, were localized using fluorescence in situ hybridization (FISH) on metaphase chromosomes of transgenic barley produced by microparticle bombardment of immature embryos. Of the 19 independent transgenic lines (eight diploid and 11 tetraploid), nine had uidA and ten had s gfp (S65T). All lines tested had three or more copies of the transgenes and 18 out of 19 lines had visibly different integration sites. At a gross level, it appeared that no preferential integration sites of foreign DNA among chromosomes were present in the lines tested; however, a distal preference for transgene integration was observed within the chromosome. In diploid T0 plants that gave a 3:1 segregation ratio of transgene expression in the T1, only single integration sites were detected on one of the homologous chromosomes. Homozygous diploid plants had doublet signals on a pair of homologous chromosomes. All tetraploid T0 plants that gave a 3:1 segregation ratio in the T1 generation had only a single integration site on one of the homologous chromosomes. In contrast, the single tetraploid T0 plant with a 35:1 segregation ratio in the T1 generation had doublet signals on a pair of homologous chromosomes. In the one tetraploid T0 line, which had a homozygote-like segregation ratio (45:0), there were doublet signals at two loci on separate chromosomes. We conclude that the application of FISH for analysis of transgenic plants is useful for the gross localization of transgene(s) and for early screening of homozygous plants.

Cold accumulation of SCOF-1 transcripts is associated with transcriptional activation and mRNA stability.

Cold acclimation enhances the transcription of several cold regulated (COR) genes. However, little is known about whether the elevation of the transcriptional level of the COR genes is due to transcriptional activation, or mRNA stability by a low temperature. Recently, we cloned a novel cold-inducible zinc finger protein gene from soybean, SCOF-1, which may function as a positive regulator of the COR gene expression . Here we report that the elevation of the SCOF-1 transcript level by cold stress is associated with both transcriptional activation and post-transcriptional mRNA stability under a low temperature. A nuclear run-on assay reveals that cold acclimation elevates the SCOF-1 transcript about three-fold compared to that of non-acclimated soybean nuclei. Furthermore, SCOF-1 transcripts increased substantially by a low temperature in transgenic tobacco plants that constitutively expressed SCOF-1 under the control of a constitutive cauliflower mosaic virus (CaMV) 35S promoter. When a transcription inhibitor, cordycepin, was treated with the deacclimating soybean cell, the decay level of the SCOF-1 transcripts was delayed significantly. This suggests that it may affect de novo protein synthesis, which degrades the SCOF-1 mRNA at room temperature. In addition, a secondary structure may be involved in the mRNA stability of SCOF-1 under a low temperature.

Redox changes accompanying the degradation of seed storage proteins in germinating rice.

The mobilization of storage proteins (glutelins) in germinating rice seeds was accompanied by an ordered sequential combination of proteolysis and reduction of disulfide groups. Mobilization was followed by application of non-reducing/reducing two dimensional-PAGE after monobromobimane labeling of the sulfhydryl groups of the proteins in intact seeds.

Anti-drug antibodies as drug carriers. I. For small molecules.

PURPOSE: To better understand the pharmacokinetics of drugs compounds that bind endogenous antibodies METHODS: Three groups of mice with differing anti-fluorescein (FL) titers were established by empirically developed immunization protocols. These with two control groups were given intravenously [3H]-ethanolamine conjugate of FL (FL-EA). The latter was synthesized using isothiocyanate chemistry. Radioactivity in the circulation, and occasionally in peritoneal ascites, was monitored for 7 days. A group of mice was immunized with eosin Y and given FL-EA. Conversely, eosin Y conjugate of radiolabeled EA (EY-EA) was given to mice immunized with FL. These two groups represented animals of low affinity to probe haptens. The affinity was assessed by a precipitation procedure, while titer was determined by a standard ELISA. Dose of FL-EA varied over a 100-fold. RESULTS: On average, the three immunized groups showed a 1:13:85 ratio of anti-FL titer, with remarkably consistent levels within each group. Elimination rates of FL-EA from the serum of very high-titer mice and high-titer mice were similar, however, were substantially lower than that found in low-titer mice. The latter was in turn lower than that found in non- or mock-immunized mice. Serum of mice immunized with FL showed approximately 200-fold lower affinity towards EY-EA than FL-EA. In these mice and in mice immunized with eosin Y and given FL-EA, the elimination of the probe haptens was again fast, reminiscent of low-titer mice. Mice of either low titer or low affinity showed more rapid redistribution of the conjugate between serum and peritoneal fluid. In a group of mice with comparable anti-FL titer, elimination from serum was independent of dose over a 100-fold difference. The bi-phasic concentration-time profile observed was accommodated by a physiologically meaningful pharmacokinetic model incorporating two compartments in which antibody binding can occur. CONCLUSIONS: Monovalent antigenic substance cannot trigger immune clearance. As such, endogenous antibodies that recognize the molecule can serve as a carrier to result in a substantial decrease in clearance.

Antibodies as drug carriers. II. For proteins.

PURPOSE: To evaluate the potential use of antibodies as a carrier for monovalent protein haptens. METHODS: A single -SH functionality present in the human IgG light chain was fluoresceinated. This conjugate, FL-LC, was treated with pepsin to obtain FL conjugate of half light chain, FL-(LC)1/2, of MW 11 kDa. These two were radiolabeled using [3H]-propionic acid N-hydroxysuccinimide ester, and administered via tail vein to FL-immunized or mock-immunized mice. The blood radioactivity was measured over a 72-h period. Attempts were made to measure the affinity constant for the interaction between the conjugates and anti-FL antibodies by fluorescence quenching, surface plasmon resonance spectroscopy, and competitive ELISA. RESULTS: All of the three methods used produced supportive, if not conclusive, evidence of decreased binding affinity with increased conjugate size. Subsequent to tail-vein injection to FL-immunized mice, FL-LC showed approximately 4-fold smaller volume of distribution than mock-immunized mice: 0.041 +/- 0.005 vs. 0.16 +/- 0.02 mL/g. Corresponding values for FL-(LC)1/2, were significantly larger: 0.070 +/-0.013 and 0.30 +/- 0.02 mL/g, respectively. Compared with a small FL conjugate of ethanolamine, FL-EA, we studied earlier, the dose-normalized concentrations of the protein conjugates started at a higher level but declined more rapidly with time. In mock-immunized mice, the radioactivity disappeared very rapidly after administration, followed by an extremely slow decline with half-life close to 60 h. Evidence is provided to support that the radiolabel dissociated in the kidney, however, binding to anti-FL antibodies greatly stabilized the conjugate. CONCLUSIONS: Based on an entropic principle alone the affinity of monovalent hapten-antibody interaction is expected to diminish with increase in hapten size. As such, the size of a hapten should be an important determinant of its pharmacokinetics in animals harboring antibodies that recognize the hapten. Relative to what was observed with small MW FL-EA, the protein conjugates showed substantially sustained circulation as a result of antibody binding, but this effect was diminished at later time points. Both affinity and pharmacokinetic data are consistent with the hypothesis of reduced affinity with increasing MW for monovalent hapten conjugates, but neither offered overwhelming proof.

High frequency of cytogenetic aberration in transgenic oat (Avena sativa L.) plants.

Cytological abnormalities were observed in transgenic oat (Avena sativa L. cv. GAF/Park-1) produced by microprojectile bombardment of mature seed-derived highly regenerative tissues. Of the plants from 48 independent transgenic lines examined, plants from only 20 lines (42%) were karyotypically normal (2n=6x=42) without detectable chromosomal aberrations; plants from 28 lines (58%) had chromosomal variation, i.e. aneuploids and structural changes. No significant difference in cytological aberration was observed between the two different culturing systems used for transformation: 57% chromosomal abnormalities in plants derived from D'BC2 medium (2.0 mg/l 2,4-D, 0.1 mg/l BAP and 5.0 &mgr;M cupric sulfate) used for tissue initiation and maintenance and 60% in plants from tissue initiated on D'BC2 and maintained on DBC3 (1.0 mg/l 2,4-D, 0.5 mg/l BAP and 5.0 &mgr;M cupric sulfate). Comparative differences in chromosomal status frequently occurred among plants regenerated from the same T(0) line. The most common cytological aberration in transgenic plants was aneuploidy, followed by deletion of chromosomal segments; no change in ploidy level was observed. In contrast, nontransgenic plants, regenerated from tissues comparable in age and culture media to that used for transgenic tissues, had a much lower percentage of karyotypic abnormality (0-14%). Our data indicate that some stress(es) imposed by the transformation process, e.g. osmotic treatment, bombardment and selection, leads to cytological variation in transgenic oat plants, an observation similar to that observed in our recent studies with transgenic barley plants.