EPOS2020/EUFOREA expert opinion on defining disease states and therapeutic goals in CRSwNP

Severe chronic rhinosinusitis with nasal polyps (CRSwNP), a form of diffuse bilateral (usually type 2) CRS, is a debilitating disease with a significant impact on quality of life (QoL). With novel knowledge and treatment options becoming available, there is a growing need to update or revise key definitions to enable communication across different specialties dealing with CRS, and to agree on novel goals of care in CRSwNP. The European Forum for Research and Education in Allergy and Airway diseases (EUFOREA) and EPOS expert members discussed how to measure treatment responses and set new treatment goals for CRSwNP. In this paper a consensus on a list of definitions related to CRSwNP is provided: control, remission, cure, recurrence/exacerbation, treatable traits, remodeling, progression, and disease modification. By providing these definitions, the involved experts hope to improve communication between all stakeholders involved in CRSwNP treatment for use in routine care, basic and clinical research and international guidelines aimed to harmonize and optimize standard of care of patients with CRSwNP in the future.

A novel method for quantitative myocardial contrast echocardiography in mice

The small size of the mouse heart frequently imparts technical challenges when applying conventional in vivo imaging methods for assessing heart function. Here, we describe the use of high-frequency ultrasound imaging in conjunction with a size-tuned blood pool contrast agent for quantitatively assessing myocardial perfusion in living mice. A perflurocarbon microbubble formulation exhibiting a narrow size distribution was developed, and echogenicity was assessed at 18 MHz in vitro. Adult mice were subjected to permanent ligation of the left anterior descending artery. Ultrasound imaging was performed on day 7, and a cohort of intact mice was used as a control. Parasternal long-axis cine clips were acquired at 18 MHz before and after contrast administration. Reduced ejection fraction and increased end-systolic volume were observed in infarcted compared with control mice. In control animals, washin of the contrast agent was visible in all myocardial segments. Reduced contrast enhancement was observed in apical-posterolateral regions of all infarcted mice. A novel method for reslicing of the imaging data through the time domain provided a two-dimensional presentation of regional contrast agent washin, enabling convenient identification of locations exhibiting altered perfusion. Myocardial segments exhibiting diminished contractility were observed to have correspondingly low relative myocardial perfusion. The contrast agent formulation and methods demonstrated here provide the basis for simplifying routine in vivo estimation of infarct size in mice and may be particularly useful in longitudinal evaluation of revascularization interventions and assessment of peri-infarct ischemia. NEW & NOTEWORTHY Murine myocardial contrast echocardiography frequently suffers from poor sensitivity to contrast. Here, we formulated a novel size-tuned microbubble contrast agent and validated it for use with ultra-high-frequency ultrasound. A novel data method for evaluating myocardial perfusion based on reslicing the imaging data through the time domain is presented.

The T-ALL related gene BCL11B regulates the initial stages of human T-cell differentiation

The initial stages of T-cell differentiation are characterized by a progressive commitment to the T-cell lineage, a process that involves the loss of alternative (myelo-erythroid, NK, B) lineage potentials. Aberrant differentiation during these stages can result in T-cell acute lymphoblastic leukemia (T-ALL). However, the mechanisms regulating the initial stages of human T-cell differentiation are obscure. Through loss of function studies, we showed BCL11B, a transcription factor recurrently mutated T-ALL, is essential for T-lineage commitment, particularly the repression of NK and myeloid potentials, and the induction of T-lineage genes, during the initial stages of human T-cell differentiation. In gain of function studies, BCL11B inhibited growth of and induced a T-lineage transcriptional program in T-ALL cells. We found previously unknown differentiation stage-specific DNA binding of BCL11B at multiple T-lineage genes; target genes showed BCL11B-dependent expression, suggesting a transcriptional activator role for BCL11B at these genes. Transcriptional analyses revealed differences in the regulatory actions of BCL11B between human and murine thymopoiesis. Our studies show BCL11B is a key regulator of the initial stages of human T-cell differentiation and delineate the BCL11B transcriptional program, enabling the dissection of the underpinnings of normal T-cell differentiation and providing a resource for understanding dysregulations in T-ALL.

N-ethoxybenzylimidazoles: a novel acid-sensitive linker for controlled release of therapeutics from drug delivery systems

Abstract #2156

Background:
 Drug delivery systems (DDS) are useful for cancer therapies because they can target tumors and cancer cells more specifically than cancer therapeutics alone. An important component of a DDS is the triggering mechanism for drug release. This presentation will highlight a new class of N-linked imidazoles as potential acid-sensitive cleavable linkers for use in cancer DDSs. These acid-sensitive linkers are designed to exploit the lower extracellular pH of some tumors and the endosomes and lysosomes within cells to trigger the controlled release of therapeutic agents from drug delivery vessels. Cleavage of N-ethoxybenzylimidazoles (NEBIs) exhibit a 10-fold increase in the rate of hydrolysis in mild aqueous acidic solutions (at pH = 5.5) compared to solutions at normal, physiological pH. The rate of hydrolysis can be tuned to range from minutes to months through the addition of electron donating or withdrawing groups.
 The NEBI linker can be used to conjugate a cytotoxic agent to a carrier. Carriers for this DDS include molecules such as tumor specific antibodies, polymers/nanoparticles, peptides, and ligands, that can target cancer cells or accumulate around tumors. Cytotoxic agents include FDA approved small molecules and chemotherapeutics.
 Methods and Materials:
 The NEBI was developed into a bifunctional crosslinker containing a carboxylic acid and an azide for conjugation of cancer therapeutics to carriers. For simplicity, we used Human Serum Albumin (HSA) as our model carrier and doxorubicin as our model cytotoxic agent. The NEBI was conjugated to doxorubicin through a simple amide coupling. The NEBI was then conjugated to an alkyne containing HSA via “Click Chemistry.”
 Results:
 We were able to load approximately 1-2 doxorubicin molecules per HSA. Imaging studies have shown that our HSA conjugates to doxorubicin via a NEBI linker (HSA-NEBI-dox) localize in lysosomes. Cytotoxicity studies show HSA-NEBI-dox is cytotoxic while HSA conjugates to doxorubicin via a stable linkage is not.
 Discussion:
 We were able to develop methods for conjugating doxorubicin to HSA. The techniques used here can be applied to conjugate other carriers and other cancer therapeutics. We will continue to develop the NEBI linker and demonstrate how the linker can be used to conjugate trastuzumab to doxorubicin. We chose use trastuzumab, a monoclonal antibody, as a carrier because it is known to bind to the HER2 receptor. HER2 is over expressed in 25%-30% of breast cancers. Trastuzumab not only targets cancer cells that are over expressing the HER2 receptor, but binding of trastuzumab to the HER2 receptor can trigger receptor mediated endocytosis, which can lead to controlled release of doxorubicin within the cell.
 


Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2156.

Unsaturated fatty acids down-regulate srebp isoforms 1a and 1c by two mechanisms in HEK-293 cells

Sterol regulatory element-binding proteins (SREBPs) are membrane-bound transcription factors that increase the synthesis of fatty acids as well as cholesterol in animal cells. All three SREBP isoforms (SREBP-1a, -1c, and -2) are subject to feedback regulation by cholesterol, which blocks their proteolytic release from membranes. Previous data indicate that the SREBPs are also negatively regulated by unsaturated fatty acids, but the mechanism is uncertain. In the current experiments, unsaturated fatty acids decreased the nuclear content of SREBP-1, but not SREBP-2, in cultured human embryonic kidney (HEK)-293 cells. The potency of unsaturated fatty acids increased with increasing chain length and degree of unsaturation. Oleate, linoleate, and arachidonate were all effective, but the saturated fatty acids palmitate and stearate were not effective. Down-regulation occurred at two levels. The mRNAs encoding SREBP-1a and SREBP-1c were markedly reduced, and the proteolytic processing of these SREBPs was inhibited. When SREBP-1a was produced by a cDNA expressed from an independent promoter, unsaturated fatty acids reduced nuclear SREBP-1a without affecting the mRNA level. There was no effect when the cDNA encoded a truncated version that was not membrane-bound. When administered together, sterols and unsaturated fatty acids potentiated each other in reducing nuclear SREBP-1. In the absence of fatty acids, sterols did not cause a sustained reduction of nuclear SREBP-1, but they did reduce nuclear SREBP-2. We conclude that unsaturated fatty acids, as well as sterols, can down-regulate nuclear SREBPs and that unsaturated fatty acids have their greatest inhibitory effects on SREBP-1a and SREBP-1c, whereas sterols have their greatest inhibitory effects on SREBP-2.

Molecular characterization of human acetyl-CoA synthetase, an enzyme regulated by sterol regulatory element-binding proteins

Through suppressive subtractive hybridization, we identified a new gene whose transcription is induced by sterol regulatory element-binding proteins (SREBPs). The gene encodes acetyl-CoA synthetase (ACS), the cytosolic enzyme that activates acetate so that it can be used for lipid synthesis or for energy generation. ACS genes were isolated previously from yeast, but not from animal cells. Recombinant human ACS was produced by expressing the cloned cDNA transiently in human cells. After purification by nickel chromatography, the 701-amino acid cytosolic enzyme was shown to function as a monomer. The recombinant enzyme produced acetyl-CoA from acetate in a reaction that required ATP. As expected for a gene controlled by SREBPs, ACS mRNA was induced when cultured cells were deprived of sterols and repressed by sterol addition. The pattern of regulation resembled the regulation of enzymes of fatty acid synthesis. ACS mRNA was also elevated in livers of transgenic mice that express dominant-positive versions of all three isoforms of SREBP. We conclude that ACS mRNA, and hence the ability of cells to activate acetate, is regulated by SREBPs in parallel with fatty acid synthesis in animal cells.

Employee attitude surveys: examining the attitudes of noncompliant employees

Employees (N = 194) from a wide variety of organizations participated in this study aimed at describing the attitudes of individuals who refuse to respond to an employee survey request (noncompliants). Noncompliants, in comparison with those individuals who would comply with the survey request, possessed greater intentions to quit, less organizational commitment, and less satisfaction toward supervisors and their own jobs. Noncompliants also possessed more negative beliefs regarding how their organization handles employee survey data (e.g., does not act on survey data). No significant differences were found for work-related demographic variables, satisfaction with pay, and satisfaction with promotion opportunities. Implications for survey research are discussed along with methods to address nonresponse and noncmpliance.

Effectivity of expression of mature forms of mutant human apolipoprotein A-I

In order to probe the structural and functional properties of a central region of apolipoprotein A-I (apoA-I), we engineered mutants of the mature form of the protein and expressed them using the baculovirus/insect cell expression system. The mutations which targeted the region of apoA-I between amino acids 140 and 150 included: (i) deletion of the region 140-150 (apoA-I(Delta140-150)); (ii) substitution of arginine 149 with valine (apoA-I(R149V)); (iii) substitution of proline 143 with alanine (apoA-I(P143A)); (iv) deletion of region 63-73 (apoA-I(Delta63-73)), which has structural properties similar to 140-150; and (v) a chimeric protein substituting amino acids 140-150 with amino acids 63-73 (apoA-I(140-150 --> 63-73)). The efficiencies of synthesis were vastly different for the various mutants as follows: apoA-I(R149V) > apoA-I(140-150 --> 63-73) > apoA-I(Delta63-73) > apoA-I(P143A) > apoA-I > apoA-I(Delta140-150). About 50% of the synthesized wild type and all apoA-I mutants was retained in the cells. During expression of apoA-I(R149V) an unusual spontaneous recombination occurred. In addition to the expected mutant, another form of apoA-I with an apparent M(r) of 36K was produced which consisted of a duplication of the amino-terminal end of apoA-I, from the prepeptide through to amino acid 62, linked to the original pre-apoA-I(R149V) sequence via a 4-amino-acid linker. Despite the fact that this form of apoA-I carries two prepeptides and consequently two cleavage sites, there was little, if any, cleavage at the internal cleavage site. During expression, less than 20% of this mutant was retained in the cells. These results demonstrate that at least in the model of insect cells, the efficiency of apoA-I synthesis, processing, and secretion depends on apoA-I secondary structure and/or folding.

Production of mature human apolipoprotein A-I in a baculovirus-insect cell system: propeptide is not essential for intracellular processing but may assist rapid secretion

To achieve expression of human mature apolipoprotein A-I (apoA-I) in the baculovirus-insect cell expression system, the propeptide encoding region of full-length preproapoA-I was deleted using polymerase chain reaction and the resulting cDNA was cloned into BacPak8 plasmid. After transfection into Sf21 insect cells and plaque purification, mature human apoA-I was secreted by the infected cells into the medium as determined by immunoblotting, amino-terminal sequencing, and molecular weight determination. In both monolayer cell cultures, and in suspension cell culture, maximum expression was achieved by the fifth day. For the first 4 days, 50 to 70% of the synthesized apoA-I was retained in the cells. This intracellular apoA-I was represented by mature apoA-I as shown by immunoblotting and amino-terminal sequencing. Further incubation resulted in a sharp decrease in the cell apoA-I content without a corresponding increase in protein in the medium and most likely represents intracellular degradation of the protein. We conclude that the deletion of the propeptide, while not preventing the correct cleavage of prepeptide during intracellular processing, results in reduced secretion of mature apoA-I. The baculovirus-insect cell expression system described in this study provides a useful method for producing recombinant mature apoA-I and is a potential tool for understanding the function of propeptide in intracellular transport and secretion of apoA-I from cells.

Noninvasive quantification of dopamine D2 receptors with iodine-123-IBF SPECT

Iodine-123-iodobenzofuran (IBF) is a potent dopamine D2 receptor ligand suited for quantitative receptor studies. The purpose of this study was to evaluate three noninvasive methods of estimating the receptor parameter k3/k4 in humans with IBF-SPECT.

METHODS

Scans were acquired every 5 min for 180 min using a triple-headed SPECT system following a bolus injection of IBF (296 +/- 37 MBq) in 14 normal volunteers. k3/k4 was estimated by the peak equilibrium ratio (RPE) method and two proposed methods: a variation of the graphic method that derives the ratio of ligand distribution volumes (RV) and area ratio (RA) method, in which the ratio is calculated from the areas under the specific binding and nondisplaceable activity curves.

RESULTS

The mean RPE, RV and RA were 2.74 +/- 0.40, 3.06 +/- 0.42 and 2.26 +/- 0.28, respectively. Both RPE and RA underestimated RV. The relationship between RPE or RA and RV was linear (p < or = 10(-5), RA showed higher correlation (r = 0.94) with RV than did RPE (r = 0.90). Simulations based on a tracer kinetic model showed that RV, unlike RPE or RA, is affected by neither regional cerebral blood flow (rCBF) nor peripheral clearance rate (CR) of IBF. All three measures showed a significant decline with increasing age (r = 0.54-0.58, p < 0.05).

CONCLUSION

RV is preferred because it provides a theoretically valid estimate of k3/k4, independently of rCBF or CR. Alternatively, RA might be preferred to RPE because the former is simpler than the latter to implement yet the former provides a measure that equally well correlates with k3/k4.

Value of standardized gestational age charts for fetuses of first-generation Oriental immigrants to Canada

OBJECTIVE

to ascertain if standard gestational age charts can be used to accurately predict the gestational age of fetuses of first-generation Oriental immigrants to Canada.

PATIENTS AND METHODS

Over a 3-year period, all patients presenting for obstetric ultrasound examinations were invited to participate in the study. The authors recorded biparietal diameter, head circumference, femur length and abdominal circumference for 139 fetuses in the second and third trimesters. A study performed in the first trimester was used as the baseline for gestational age. The data for 126 of the fetuses were complete, and these data were used for the analysis.

RESULTS

For 77 of the fetuses, both parents were Oriental, and for 49, one or both parents were not Oriental; the latter constituted the control group. A total of 1008 individual measurements were obtained, and of these, all but 14 fell within two standard deviations of the norm, according to standard gestational age charts. Of the abnormal measurements, seven were obtained from five fetuses with Oriental parents, and seven were obtained from six fetuses in the control group. The difference between the two groups in the proportion of measurements falling either above or below two standard deviations from the norm was not statistically significant (Fisher's exact test, p = 0.41694).

CONCLUSION

The authors conclude that standard gestational age charts can be used to determine gestational age in first-generation Oriental immigrants to Canada.