Movement of the feline esophagus associated with respiration and peristalsis. An evaluation using tantalum markers

The outer, lateral esophageal walls in the distal half of the esophagus in each of five cats were labeled with small tantalum wires. About 8 wk later, esophageal motion associated with respiration and peristalsis, induced by injecting barium boli (5 ml each) into the proximal esophagus, was recorded on cine and serial biplane roentgenograms while recording intraluminal esophageal pressures simultaneously by manometry. Esophageal motion was also evaluated without a manometric tube in place. The coordinates for each marker were digitized and a computer was used to plot marker position against time. During respiration, the markers passively made a shallow, 2-10 mm excursion on the longitudinal esophageal axis. This movement was synchronous with thoracic and diaphragmatic movement and changes in intraluminal esophageal pressure. Immediately after the onset of peristalsis, the markers made a pronounced oral movement of 10 mm or more above their mean respiratory position, as if to engulf the bolus. Markers in opposing esophageal walls approximated one another and commenced an aboral movement as the bolus tail, which was essentially co-incident with onset of the manometric pressure complex, passed the marker sites. The markers returned to their respective rest positions essentially coincident with passage of the pressure complex peak and then moved below their respective rest positions. The aboral excursion occurred predominantly after the bolus had emptied into the stomach. The magnitude and duration of oral excursion was significantly greater for the distal than for the more proximal markers; conversely, the magnitude and duration of aboral excursion was greater for the proximal than for the more distal markers. During the peristaltic sequence, the labeled portion of the esophagus shortened from 26 to 46% of its resting length. No evidence of esophageal torque was shown. These findings suggest that both the longitudinal and circular esophageal musculature play an active and important role during peristaltic transport of a bolus through the esophagus.

Uptake of (3H)progesterone and (3H)5alpha-dihydroprogesterone by rat tissues in vivo and analysis of accumulated radioactivity: accumulation of 5alpha-dihydroprogesterone by pituitary and hypothalamic tissues

These in vivo studies explored the possibility that the metabolism of progesterone to 5alpha-dihydroprogesterone (5alpha-DHP) and 3alpha-hydroxy-5alpha-pregnan-20-one in hypothalamus and pituitary may influence gonadotropin release. [3H]progesterone or [3H]5alpha-DHP was injected iv into ovariectomized or ovariectomized-adrenalectomized rats for 10 0r 30 min. 3H content was determined for plasma, anterior pituitary, medial basal hypothalamus (MBH), cerebral cortex, muscle and uterus. Isotopic dilution analyses of the accumulated 3H were made for progesterone, 5alpha-DHP, 3alpha-hydroxy-5alpha-pregnan-20-one, 20alpha-dihydroprogesterone, 20alpha-hydroxy-5alpha-pregnan-3-one, and 5alpha-pregnane-3alpha, 20alpha-diol on samples from the 10 min groups. With progesterone injections, most of the tissue 3H was distributed among progesterone, 5alpha-DHP, and 3alpha-hydroxy-5alpha-pregnan-20-one. Progesterone was the predominant 3H-steroid in uterus, MBH, cerebral cortex and muscle. [3H]5alpha-DHP was the other major 3H-steroid in MBH and the predominant one in pituitary. In terms of tissue/plasma concentration comparisons, no tissue concentration of [3H]progesterone was greater than that in plasma except for MBH in the ovariectomized-adrenalectomized group. In contrast, [3H]5alpha-DHP levels in pituitary, MBH and cerebral cortex were many fold greater than those in plasma and muscle. MBH and pituitary levels were significantly greater than that in cerebral cortex. With 5alpha-DHP injections, most tissue 3H was associated with 5alpha-DHP and/or 3alpha-hydroxy-5alpha-pregnan-20-one. No [3H]progesterone was detected. [3H]5alpha-DHP predominated in pituitary and MBH, while 3alpha-hydroxy-5alpha-pregnan-20-one predominated in the others. In terms of tissue and plasma concentration comparisons, MBH, pituitary and cerebral cortical concentrations of [3H]5alpha-DHP were markedly higher than plasma, muscle, and uterine levels. Pituitary and MBH concentrations were also greater than that in cerebral cortex. Tissue levels of [3H]3alpha-hydroxy-5alpha-pregnan-20-one were not significantly greater than that in plasma. Thus, 10 min after injection of either [3H]progesterone or [3H]5alpha-DHP, high and significant amounts of 5alpha-DHP are accumulated in pituitary and hypothalamus, but not in uterus, which suggests that its presence may be functionally important in governing progesterone-sensitive processes in these feedback tissues.

Heterogeneity of insulin-like growth factor-I affinity for the insulin-like growth factor-II receptor: comparison of natural, synthetic and recombinant DNA-derived insulin-like growth factor-I

Although insulin-like growth factors (IGF) I and II bind with high affinity to structurally discrete receptors, they bind with a lesser affinity to each other's receptor. We have evaluated the affinity of five different IGF-I preparations (three natural IGF-I preparations, one synthetic preparation, and one recombinant DNA-derived) for the IGF-II receptor in rat placental membranes, 18-54,SF cells and BRL-3A cells. In all tissues tested, the natural IGF-I preparations demonstrated an affinity for the IGF-II receptor which was 10-20% that of IGF-II. However, the recombinant and synthetic IGF-I preparations exhibited substantially lower affinities than natural IGF-I for this receptor, with only 10-25% reduction in (125-I)iodo IGF-II binding at peptide concentrations up to 400 ng/ml. Radioimmunoassay of the natural IGF-I preparations with an antibody directed against the unique C-peptide region of IGF-II demonstrated that contamination of IGF-I preparations with immunoreactive IGF-II could not exceed 5%. These results demonstrate that IGF-I purified from human plasma has a different affinity for the IGF-II receptor than does synthetic or recombinant IGF-I. Furthermore, these data are consistent with the hypothesis that IGF-I, itself, may be heterogeneous, and that subforms may vary in their affinities for the IGF receptors. Alternatively, IGF-I preparations which have been considered to be pure may be contaminated with small amounts of IGF-II, resulting in overestimation of the affinity of IGF-I for the type II IGF receptor.

Transformation of Drosophila melanogaster with the wild-type myosin heavy-chain gene: rescue of mutant phenotypes and analysis of defects caused by overexpression

We have transformed Drosophila melanogaster with a genomic construct containing the entire wild-type myosin heavy-chain gene, Mhc, together with approximately 9 kb of flanking DNA on each side. Three independent lines stably express myosin heavy-chain protein (MHC) at approximately wild-type levels. The MHC produced is functional since it rescues the mutant phenotypes of a number of different Mhc alleles: the amorphic allele Mhc1, the indirect flight muscle and jump muscle-specific amorphic allele Mhc10, and the hypomorphic allele Mhc2. We show that the Mhc2 mutation is due to the insertion of a transposable element in an intron of Mhc. Since a reduction in MHC in the indirect flight muscles alters the myosin/actin protein ratio and results in myofibrillar defects, we determined the effects of an increase in the effective copy number of Mhc. The presence of four copies of Mhc results in overabundance of the protein and a flightless phenotype. Electron microscopy reveals concomitant defects in the indirect flight muscles, with excess thick filaments at the periphery of the myofibrils. Further increases in copy number are lethal. These results demonstrate the usefulness and potential of the transgenic system to study myosin function in Drosophila. They also show that overexpression of wild-type protein in muscle may disrupt the function of not only the indirect flight but also other muscles of the organism.

Characterization of a CC49-based single-chain fragment-beta-lactamase fusion protein for antibody-directed enzyme prodrug therapy (ADEPT)

CC49 is a clinically validated antibody with specificity for TAG-72, a carbohydrate epitope that is overexpressed and exposed on the cell surface in a large fraction of solid malignancies. We constructed a single-chain fragment (scFv) based on CC49 and fused it to beta-lactamase (BLA). Following optimization of the scFv domain by combinatorial consensus mutagenesis (CCM) for increased expression and stability, we characterized the protein variant for binding, in vivo pharmacokinetics (PK), and antitumor efficacy. The fusion protein TAB2.5 possessed a similar binding specificity relative to the parent antibody CC49. TAB2.5 also showed prolonged retention (T(1/2) = 36.9 h) in tumor-bearing mice with tumor/plasma ratios of up to 1000. Preliminary evaluation of TAB2.5, in combination with a novel prodrug, GC-Mel, resulted in significant efficacy in a colorectal xenograft tumor model and supports the utility of the protein as an agent for tumor-selective prodrug activation.

Endoscopic hemorrhoidal ligation: preliminary clinical experience

BACKGROUND

Endoscopic hemorrhoidal ligation may provide an alternative to surgical treatment of internal hemorrhoids. This study assessed the safety and efficacy of endoscopic elastic band ligation for bleeding internal hemorrhoids.

METHODS

Endoscopic hemorrhoid ligation was performed in 20 adult patients who had chronic rectal bleeding attributed to internal hemorrhoids. Elastic band ligation was accomplished using a ligating device attached to the end of a video endoscope. Repeat endoscopy was done 3 weeks after the initial procedure.

RESULTS

Seventy band ligations were performed during 23 separate sessions. Post-therapy endoscopy showed reduction of hemorrhoidal size by at least one grade in 19 of 20 patients (95%). Bleeding resolved in 19 of 20 patients (95%) in 5.4 months (mean) of follow-up; 18 of 20 (90%) required only one banding session. No major complications (perforation, secondary bleeding, deep ulceration) occurred in this small group.

CONCLUSIONS

Preliminary data indicates that endoscopic hemorrhoidal ligation is a safe and effective technique for treating internal hemorrhoids. It holds promise as an important technique for successfully treating and possibly eradicating symptomatic internal hemorrhoids.

Purification of the insulin-like growth factor II (IGF-II) receptor from an IGF-II-producing cell line, and generation of an antibody which both immunoprecipitates and blocks the type 2 IGF receptor

18,54-SF cells, which secrete rat insulin-like growth factor II (rIGF-II), have abundant type 2 IGF receptors. We have purified the type 2 receptor from these cells by solubilization of crude membranes in Triton X-100, followed by chromatography on agarose-immobilized rIGF-II. A partially purified receptor preparation, obtained by chromatography of solubilized membranes over wheat germ agglutinin, was used to immunize a rabbit. The antibody generated both immunoprecipitates the type 2 receptor, and specifically inhibits IGF-II binding to a variety of rat tissues, including 18,54-SF cells, BRL-3A cells and placenta. The presence of abundant type 2 receptors on an rIGF-II-secreting cell line is consistent with an autocrine role for IGF-II in select cells.

Suboptimal 5' and 3' splice sites regulate alternative splicing of Drosophila melanogaster myosin heavy chain transcripts in vitro

Using a Drosophila cell-free system, we have analyzed the regulation of alternative splicing of Drosophila muscle myosin heavy chain (MHC) transcripts. Splicing of MHC 3' end transcripts results in exclusion of adult-specific alternative exon 18, as is observed in embryonic and larval muscle in vivo. Mutations that strengthen either the 5' or the 3' splice sites of exon 18 do not promote inclusion of this exon. However, strengthening both splice junctions results in efficient removal of both introns and completely inhibits skip splicing. Our data suggest that the affinity of exons 17 and 19, as well as failure of constitutive splicing factors to recognize exon 18 splice sites, causes the exclusion of exon 18 in wild-type transcripts processed in vitro.

Detection of multiple papillary fibroelastomas of the tricuspid valve by transesophageal echocardiography

A 66-year-old man without symptoms, referred for the treatment of moderate hypertension, was found to have a right atrial mass by two-dimensional echocardiography. On transesophageal echocardiography two masses were detected on the tricuspid valve, the first one on the posterior leaflet and the second smaller one on the anterior leaflet. These findings were confirmed at surgery. Histologic analysis revealed that the masses represented papillary fibroelastomas.

Identification of receptors for insulin-like growth factor II in two insulin-like growth factor II producing cell lines

Specific high affinity membrane receptor(s) for insulin-like growth factor II have been characterized in two cell lines which produce this hormone and have the ability to proliferate in serum-free media. These receptor(s) have no affinity for either insulin or biosynthetic insulin-like growth factor I. Affinity cross-linking and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed an apparent Mr of 250K which does not change with disulfide bond reduction. Our findings are consistent with an autocrine function for insulin-like growth factor II and indicate that these continuous cell lines may provide unique systems for further investigations of this hormone and its receptor.

Hypertensive vascular disease as a cause of death in blacks versus whites: autopsy findings in 587 adults

Cardiovascular disease is the major cause of excess mortality among urban US blacks, but autopsy data comparing black-white differences in underlying pathological causes of cardiovascular death are lacking. We reviewed all 720 adult cases autopsied in 1991 in the New York City Medical Examiner's Office in which the coded cause of death was cardiovascular disease (International Classification of Diseases, 9th Revision, codes 391, 393 to 398, 401 to 404, 410, 411, 414 to 417, 420 to 438, and 440 to 444). After exclusion of 133 cases because race was missing or coded as other than black or white, gender was not coded, or there was an unusual circumstances of death or extreme obesity, 587 cases were available for analysis. There were 314 black and 273 white subjects. Black women were younger than white women at time of death (mean age, 54.7 versus 61.5 years; P<.001), whereas black and white men did not differ in mean age at death. Hypertensive vascular disease was the autopsy cause of death in 42% of blacks compared with 23% of whites (P<.001). Conversely, atherosclerotic heart disease was the autopsy cause of death in 64% of white subjects but only 38% of blacks. These patterns were consistent in both sexes and after adjustment for age. Hypertensive vascular disease was far more common than atherosclerotic heart disease as the cause of death at autopsy among blacks compared with whites in New York City, whereas atherosclerotic heart disease was more common in whites. These findings suggest that ineffective control of hypertension is a major factor contributing to excess cardiovascular mortality among urban blacks.

The Role of Anti-Drug Antibodies in the Pharmacokinetics, Disposition, Target Engagement, and Efficacy of a GITR Agonist Monoclonal Antibody in Mice

Administration of biologics to enhance T-cell function is part of a rapidly growing field of cancer immunotherapy demonstrated by the unprecedented clinical success of several immunoregulatory receptor targeting antibodies. While these biologic agents confer significant anti-tumor activity through targeted immune response modulation, they can also elicit broad immune responses potentially including the production of anti-drug antibodies (ADAs). DTA-1, an agonist monoclonal antibody against GITR, is a highly effective anti-tumor treatment in preclinical models. We demonstrate that repeated dosing with murinized DTA-1 (mDTA-1) generates ADAs with corresponding reductions in drug exposure and engagement of GITR on circulating CD3(+) CD4(+) T cells, due to rapid hepatic drug uptake and catabolism. Mice implanted with tumors after induction of preexisting mDTA-1 ADA show no anti-tumor efficacy when given 3 mg/kg mDTA-1, an efficacious dose in naive mice. Nonetheless, increasing mDTA-1 treatment to 30 mg/kg in ADA-positive mice restores mDTA-1 exposure and GITR engagement on circulating CD3(+) CD4(+) T cells, thereby partially restoring anti-tumor efficacy. Formation of anti-mDTA-1 antibodies and changes in drug exposure and disposition does not occur in GITR(-/-) mice, consistent with a role for GITR agonism in humoral immunity. Finally, the administration of muDX400, a murinized monoclonal antibody against the checkpoint inhibitor PD-1, dosed alone or combined with mDTA-1 did not result in reduced muDX400 exposure, nor did it change the nature of the anti-mDTA-1 response. This indicates that anti-GITR immunogenicity may not necessarily impact the pharmacology of coadministered monoclonal antibodies, supporting combination immunomodulatory strategies.

The role of evolutionarily conserved sequences in alternative splicing at the 3' end of Drosophila melanogaster myosin heavy chain RNA

Exon 18 of the muscle myosin heavy chain gene (Mhc) of Drosophila melanogaster is excluded from larval transcripts but included in most adult transcripts. To identify cis-acting elements regulating this alternative RNA splicing, we sequenced the 3' end of Mhc from the distantly related species D. virilis. Three noncoding regions are conserved: (1) the nonconsensus splice junctions at either end of exon 18; (2) exon 18 itself; and (3) a 30-nucleotide, pyrimidine-rich sequence located about 40 nt upstream of the 3' splice site of exon 18. We generated transgenic flies expressing Mhc mini-genes designed to test the function of these regions. Improvement of both splice sites of adult-specific exon 18 toward the consensus sequence switches the splicing pattern to include exon 18 in all larval transcripts. Thus nonconsensus splice junctions are critical to stage-specific exclusion of this exon. Deletion of nearly all of exon 18 does not affect stage-specific utilization. However, splicing of transcripts lacking the conserved pyrimidine sequence is severely disrupted in adults. Disruption is not rescued by insertion of a different polypyrimidine tract, suggesting that the conserved pyrimidine-rich sequence interacts with tissue-specific splicing factors to activate utilization of the poor splice sites of exon 18 in adult muscle.

Conversion of 17 alpha-hydroxyprogesterone to 5 alpha, 3 alpha, and 20 alpha-reduced metabolites by female rat anterior pituitary and hypothalamus

The metabolism of 17 alpha-[3H]hydroxyprogesterone was examined in female rat anterior pituitary and hypothalamic tissues. After reverse isotopic dilution analysis and purification to constant specific activity, the following 5 alpha-, 3 alpha- and 20 alpha-reduced products were detected in both tissues: 17 alpha-hydroxy-5 alpha-pregnane-3,20-dione; 3 alpha,17 alpha-dihydroxy-5 alpha-pregnan-20-one; 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one and 5 alpha-pregnane-3 alpha,17 alpha,20 alpha-triol. While the metabolites formed were qualitatively the same, there were quantitative differences between the two tissues. The 3 alpha,5 alpha-reduced metabolite, 3 alpha,17 alpha-dihydroxy-5 alpha-pregnan-20-one, was the principal product in the anterior pituitary while the 5 alpha-reduced metabolite, 17 alpha-hydroxy-5 alpha-pregnane-3,20-dione, was produced in largest amount by the hypothalamus. With both tissues, the aforementioned four products plus starting substrate accounted for nearly all of the starting radioactivity. There was no evidence for the formation of C19 steroids (androgens) despite the presence of the 17 alpha-hydroxy group.

Creating a framework for the prioritization of biosecurity risks to the New Zealand dairy industry

The New Zealand dairy sector relies on robust biosecurity measures to control and mitigate a wide range of threats to the industry. To optimize the prioritization of organisms and manage the risk they pose to the sector in a transparent and credible way, the Dairy Biosecurity Risk Evaluation Framework (D-BRiEF) was developed. This comprehensive framework was specifically designed for decision support, using a standardized approach to address the full spectrum of biosecurity threats to the sector, including exotic and endemic animal disease organisms, pest plants and insects. D-BRiEF is underpinned by three main processes, namely (i) hazard identification; (ii) multicriteria risk assessment; and (iii) communication for risk management. Expert knowledge and empirical data, including associated uncertainty, are harnessed in a standardized format. Results feed into a probability-impact model that was developed in close collaboration with dairy sector economists to provide overall comparative 10-year quantitative economic impact estimates for each assessed risk organism. A description of the overarching framework, which applies to diverse organism groups, is presented with detailed methodology on both endemic and exotic animal disease risk organisms. Examples of visual outputs are included, although actual ranking results are not reported due to industry confidentiality. D-BRiEF can provide a decision advantage to DairyNZ biosecurity risk managers and sector stakeholders by creating a transparent process that can be interrogated and updated at multiple levels to fully understand the layers of risk posed by different organisms.

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

Abstract 4521: Evaluation of the relationship between serum exposure, receptor (GITR) availability and tumor suppression following administration of the anti-GITR antibody DX400 in mouse syngeneic tumor models

GITR is a type I transmembrane protein of the tumor necrosis factor receptor superfamily which is expressed primarily on T lymphocytes and natural killer cells. Ligation of GITR on activated T cells provides a costimulatory signal that positively modulates antigen-specific T cell responses, leading to enhanced cellular and humoral immunity. The anti-GITR antibody DX400 is a murinized agonistic monoclonal antibody that targets mouse GITR, and has shown tumor growth inhibition in mouse syngeneic tumor models. In this study we examined the pharmacokinetic/pharmacodynamics (PK/PD) properties of DX400. Studies were conducted to examine the potential relationships between anti-GITR antibody serum exposure (PK) and receptor availability (PD) on the relevant T-cell subsets. The concentrations of DX400 in serum were determined using an electrochemiluminescence (ECL) assay, and the availability of receptor (GITR) was determined using flow cytometry. Non-linear PK properties for DX400 were observed over the dose range examined. In line with changes in serum concentration-time profiles for the antibody, a dose dependent effect in receptor availability was also observed. The relationships between receptor availability, serum concentrations of DX400 and tumor suppression were described by a mechanistic PK/PD model. This analysis provided an estimated potency (EC50) value of 4.2 ng/mL for blood receptor engagement on T-cell subsets.

Citation Format: Ayse Meric Ovacik, Natalie Shinsky-Bjorde, Douglas Hodges, Svetlana Antonenko, Roanna Ueda, Smita Mauze, Danling Gu, Derek Wiswell, Shuli Zhang, Amy Beebe, Mohammad Tabrizi. Evaluation of the relationship between serum exposure, receptor (GITR) availability and tumor suppression following administration of the anti-GITR antibody DX400 in mouse syngeneic tumor models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4521. doi:10.1158/1538-7445.AM2015-4521