Lower Extremity Revascularization Using Optical Coherence Tomography-Guided Directional Atherectomy: Final Results of the EValuatIon of the PantheriS OptIcal COherence Tomography ImagiNg Atherectomy System for Use in the Peripheral Vasculature (VISION) Study.

PURPOSE: To evaluate the safety and efficacy of a novel optical coherence tomography (OCT)-guided atherectomy catheter in treating patients with symptomatic femoropopliteal disease. METHODS: The VISION trial ( ClinicalTrials.gov identifier NCT01937351) was a single-arm, multicenter, global investigational device exemption study enrolling 158 subjects (mean age 67.2±10.5 years; 87 men) across 20 participating sites. In this cohort, 198 lesions were treated with an average length of 53±40 mm using the Pantheris catheter alone or Pantheris + adjunctive therapy. The primary safety endpoint was the composite of major adverse events (MAEs) through 6 months (objective performance goal 43.2%). Technical success (primary efficacy outcome) was defined as the percent of target lesions with a residual diameter stenosis ≤50% after treatment with the Pantheris device alone (objective performance goal 87.0%). Procedural success was defined as reduction in stenosis to ≤30% after Pantheris ± adjunctive therapy. Tissue specimens retrieved from each treated lesion were histologically analyzed to evaluate the accuracy and precision of OCT image guidance. RESULTS: The primary efficacy outcome was achieved in 192 (97.0%) of the 198 lesions treated with the Pantheris catheter. Across all lesions, mean diameter stenosis was reduced from 78.7%±15.1% at baseline to 30.3%±11.8% after Pantheris alone (p<0.001) and to 22.4%±9.9% after Pantheris ± adjunctive therapy (p<0.001). Of the 198 target lesions, 104 (52.5%) were treated with the Pantheris alone, 84 (42.4%) were treated with Pantheris + adjunctive angioplasty, and 10 (5.1%) with Pantheris + angioplasty + stenting. The composite MAE outcome through 6 months occurred in 25 (16.6%) of 151 subjects. There were no clinically significant perforations, 1 (0.5%) catheter-related dissection, 4 (2%) embolic events, and a 6.4% clinically driven target lesion revascularization rate at 6 months. The 40-lesion chronic total occlusion (CTO) subset (mean lesion length 82±38 mm) achieved a similar significant reduction in stenosis to 35.5%±13.6% after Pantheris alone (p<0.001). Histological analysis of atherectomy specimens confirmed <1% adventitia in 82.1% of the samples, highlighting the precision of OCT guidance. Characterization of the OCT-guided lesions revealed evidence of an underestimation of disease burden when using fluoroscopy. CONCLUSION: OCT-guided atherectomy for femoropopliteal disease is safe and effective. Additionally, the precision afforded by OCT guidance leads to greater removal of plaque during atherectomy while sparing the adventitia.

Should bone scintigraphy be used as a routine adjunct to skeletal survey in the imaging of non-accidental injury? A 10 year review of reports in a single centre.

AIM: To retrospectively analyse the bone scintigraphy (BS) and skeletal survey (SS) data to evaluate the role and limitations of BS in the diagnosis of non-accidental injury (NAI). MATERIALS AND METHODS: All SS and BS performed over a 10 year period, for possible NAI, in children under 2 years old were retrospectively reviewed. Reports were compared in cases where both studies were performed and findings classified into one of three groups: (1) congruent: both reports agreed; (2) BS added confidence to the SS findings; (3) BS demonstrated a new finding. False-positive and false-negative rates for BS were calculated. RESULTS: One hundred and sixty-six patients had both SS and BS. The findings were congruent in 74% of cases. BS added confidence to the SS findings in 8% and revealed a new abnormality in 4% of patients. BS demonstrated false-positive and -negative rates of 2% and 13%, respectively. Occult bony injury was detected in 12% of the 237 patients imaged. DISCUSSION: When used as an adjunct to SS in the investigation of NAI, BS can aid the confidence of diagnosis or identify new findings in 12% of cases. In centres where nuclear medicine is readily available and there is appropriate expertise in paediatric BS, this modality provides a time-effective alternative to follow-up SS at 10-14 days.

Deterministic switching of ferromagnetism at room temperature using an electric field.

The technological appeal of multiferroics is the ability to control magnetism with electric field. For devices to be useful, such control must be achieved at room temperature. The only single-phase multiferroic material exhibiting unambiguous magnetoelectric coupling at room temperature is BiFeO3 (refs 4 and 5). Its weak ferromagnetism arises from the canting of the antiferromagnetically aligned spins by the Dzyaloshinskii-Moriya (DM) interaction. Prior theory considered the symmetry of the thermodynamic ground state and concluded that direct 180-degree switching of the DM vector by the ferroelectric polarization was forbidden. Instead, we examined the kinetics of the switching process, something not considered previously in theoretical work. Here we show a deterministic reversal of the DM vector and canted moment using an electric field at room temperature. First-principles calculations reveal that the switching kinetics favours a two-step switching process. In each step the DM vector and polarization are coupled and 180-degree deterministic switching of magnetization hence becomes possible, in agreement with experimental observation. We exploit this switching to demonstrate energy-efficient control of a spin-valve device at room temperature. The energy per unit area required is approximately an order of magnitude less than that needed for spin-transfer torque switching. Given that the DM interaction is fundamental to single-phase multiferroics and magnetoelectrics, our results suggest ways to engineer magnetoelectric switching and tailor technologically pertinent functionality for nanometre-scale, low-energy-consumption, non-volatile magnetoelectronics.

Clinical outcome of an extended proximal seal zone with the AFX endovascular aortic aneurysm system.

OBJECTIVE: Despite improvements in endograft technology, operator skill, and patient selection, endovascular aneurysm repair continues to be associated with device-related complications. A retrospective, observational study was undertaken to evaluate the clinical outcome and imaging findings of a unique device having externally-mounted, conformable graft material. METHODS: Infrarenal abdominal aortic aneurysms were treated with the Endologix, Inc AFX endovascular aortic aneurysm system (Irvine, Calif) endograft in 108 consecutive patients over a 25-month period at two U.S. clinical sites. Baseline characteristics and procedural outcomes were reviewed by independent monitors. Serial computed tomography (CT) imaging assessments were performed by an independent core laboratory. Aortic neck characteristics and graft apposition were analyzed from center line-reformatted CT data sets in 37 patients in an imaging cohort comprising subjects with high-resolution baseline and follow-up CT imaging for precise assessment of aortic neck characteristics. The mean follow-up was 11 ± 5 months overall, 9 ± 6 months in patients with core laboratory imaging, and 5 ± 2 months for patients in the imaging cohort. RESULTS: Among the 108 patients, 103 (95%) had intact aneurysms and five (4.6%) were treated for rupture; 80 (74%) were male and 28 (26%) were female. On average, 2.3 ± 0.7 endograft components were implanted per patient and no adjunctive proximal neck bare stents were used. There were no perioperative deaths in patients with intact aneurysms; two patients who presented with ruptured aortic aneurysms (40%) died. Major adverse events occurred within 30 days of implantation in two patients (1.9%) with intact aneurysms. Type II endoleaks were evident on completion angiography in 18 patients (16.7%). Core laboratory analysis of CT studies identified two patients with type Ia endoleaks (2.3%), two with type III endoleaks (2.3%), and five with type II endoleaks (5.7%). Aneurysm-related secondary procedures were required in five patients over the first year of follow-up (4.6%). No patient developed endograft limb occlusion or aneurysm rupture and there were no open surgical conversions. In the imaging cohort, 360° graft-to-aortic wall apposition was continuous over a length of 25 ± 17 mm and extended the seal zone an average of 5 mm beyond the end of the anatomic neck. Early sac regression was correlated with neck length (P = .019) and graft-to-aortic apposition surface area (P = .039). CONCLUSIONS: The real-world use of the AFX endograft was associated with a low rate of device-and procedure-related complications. The ability to achieve an extended seal zone beyond the anatomical neck might in part contribute to positive outcomes, including the low type Ia and type II endoleak rate. These findings suggest that the AFX device might offer some advantages over other currently marketed endografts, but confirmation awaits the availability of longer-term outcome data.

Final results of the Chronic Total Occlusion Crossing With the Ocelot System II (CONNECT II) study.

PURPOSE: To evaluate the safety and effectiveness of the optical coherence tomography-guided Ocelot catheter to cross femoropopliteal chronic total occlusions (CTOs). METHODS: The CONNECT II study was a prospective, multicenter, non-randomized single-arm study of the safety and effectiveness of the Ocelot catheter in CTO crossing. Key inclusion criteria were a 99% to 100% stenosed femoropopliteal segment, lesion length between 1 and 30 cm, and resistance to guidewire crossing. The main exclusion criterion was a severely calcified target vessel. The primary safety endpoint was 30-day major adverse events (MAE), while the primary effectiveness endpoint was successful CTO crossing (i.e., guidewire placement in the distal true lumen) with the Ocelot catheter. Endpoint analysis was based on pre-specified objective performance criteria. Between February and June 2012, 100 patients (55 men; mean age 69 years) were enrolled. Most of the CTOs (94%) were in the superficial femoral artery (SFA); mean lesion length was 16.6±9.3 cm. RESULTS: Through 30 days, 2 patients experienced MAE (significant perforations) related to the Ocelot catheter. The Ocelot catheter successfully crossed 97% of target CTOs either alone (72%), in conjunction with an assist device (18%), or in conjunction with a re-entry device (7%). Both primary safety and effectiveness endpoints were met. CONCLUSION: The Ocelot catheter with optical coherence tomography guidance offers physicians a reliable option for crossing femoral and popliteal chronic total occlusions with low MAE rates.

Crossing chronic total occlusions with the Ocelot system: the initial European experience.

AIMS: The aim of the study was to determine the safety, efficacy and feasibility of a new chronic total occlusion (CTO) device using optical coherence tomography (OCT) technology, the Ocelot catheter (Avinger, Inc., Redwood City, CA, USA), for crossing of SFA CTOs following guidewire failure. METHODS AND RESULTS: Prospective, multicentre, market preference testing. Thirty-three patients with confirmed CTO (99-100% stenosis by visual estimate) of their superficial femoral artery (SFA) were treated between September 28, 2011, and December 9, 2011, at three European centres. Ocelot crossed 94% (31/33) of CTOs, allowing guidewire placement in the distal true lumen. All (100%) lesions were treated without any major adverse safety events. Procedural time and contrast dose were significantly reduced (p<0.0001) when compared with a similar, non-OCT-guided CTO crossing device (Wildcat catheter; Avinger, Inc.). Overall physician feedback on the catheter performance was positive with an 87% average rating of excellent or good across seven categories. Performance ratings of Ocelot's OCT imaging guidance were consistently positive with an 86% average rating of excellent or good across five OCT categories. CONCLUSIONS: The Ocelot catheter combines advanced CTO crossing technology with real-time OCT guidance. When compared with a similar non-OCT-guided catheter, crossing efficacy and safety profile improved. Total procedure time and contrast volumes were significantly reduced. The Ocelot is a safe, efficient and effective tool for crossing CTOs.

Stromal control of oncogenic traits expressed in response to the overexpression of GLI2, a pleiotropic oncogene.

Hedgehog signaling is often activated in tumors, yet it remains unclear how GLI2, a transcription factor activated by this pathway, acts as an oncogene. We show that GLI2 is a pleiotropic oncogene. The overexpression induces genomic instability and blocks differentiation, likely mediated in part by enhanced expression of the stem cell gene SOX2. GLI2 also induces transforming growth factor (TGF)B1-dependent transdifferentiation of foreskin and tongue, but not gingival fibroblasts into myofibroblasts, creating an environment permissive for invasion by keratinocytes, which are in various stages of differentiation having downregulated GLI2. Thus, upregulated GLI2 expression is sufficient to induce a number of the acquired characteristics of tumor cells; however, the stroma, in a tissue-specific manner, determines whether certain GLI2 oncogenic traits are expressed.

Endovascular repair of a chronic aortocaval fistula using a thoracic aortic endoprosthesis.

Penetrating abdominal trauma with injury to the aorta and vena cava usually requires emergent intervention and is frequently lethal. Formation of a chronic aortocaval fistula (ACF) is an uncommon late complication of these injuries. We report a case of an ACF presenting 17 years after a gunshot wound to the abdomen, with progressive congestive heart failure as the presenting symptom. The ACF was successfully treated with an endoprosthesis designed for the thoracic aorta.

A large field CCD system for quantitative imaging of microarrays.

We describe a charge-coupled device (CCD) imaging system for microarrays capable of acquiring quantitative, high dynamic range images of very large fields. Illumination is supplied by an arc lamp, and filters are used to define excitation and emission bands. The system is linear down to fluorochrome densities <<1 molecule/microm2. The ratios of the illumination intensity distributions for all excitation wavelengths have a maximum deviation approximately +/-4% over the object field, so that images can be analyzed without computational corrections for the illumination pattern unless higher accuracy is desired. Custom designed detection optics produce achromatic images of the spectral region from approximately 450 to approximately 750 nm. Acquisition of a series of images of multiple fluorochromes from multiple arrays occurs under computer control. The version of the system described in detail provides images of 20 mm square areas using a 27 mm square, 2K x 2K pixel, cooled CCD chip with a well depth of approximately 10(5) electrons, and provides ratio measurements accurate to a few percent over a dynamic range in intensity >1000. Resolution referred to the sample is 10 microm, sufficient for obtaining quantitative multicolor images from >30,000 array elements in an 18 mm x 18 mm square.

Correlations between adhesion hysteresis and friction at molecular scales.

Correlations between adhesion hysteresis and local friction are theoretically and experimentally investigated. The model is based on the classical theory of adhesional friction, contact mechanics, capillary hysteresis, and nanoscale roughness. Adhesion hysteresis was found to scale with friction through the scaling factor containing a varying ratio of adhesion energy over the reduced Young's modulus. Capillary forces can offset the relationship between adhesion hysteresis and friction. Measurements on a wide range of engineering samples with varying adhesive and elastic properties confirm the model. Adhesion hysteresis is investigated under controlled, low humidity atmosphere via ultrasonic force microscopy. Friction is measured by the friction force microscopy.

Recurrence of chronic venous ulcers on the basis of clinical, etiologic, anatomic, and pathophysiologic criteria and air plethysmography.

INTRODUCTION: Leg ulcers associated with chronic venous insufficiency (CVI) frequently recur after healing. The risk of recurrence has not been well defined for patients in different anatomic and hemodynamic groups. We reviewed the risk of ulcer recurrence on the basis of clinical, etiologic, anatomic, and pathophysiologic criteria and hemodynamic characteristics of the affected limb as assessed with air plethysmography (APG). METHODS: Ninety-nine limbs with class 6 CVI were assessed clinically and with standing duplex ultrasound scanning and APG for the definition of clinical, etiologic, anatomic, and pathophysiologic criteria. Leg ulcers were treated with high-pressure compression protocols. Surgical correction of venous abnormalities was offered to patients with appropriate conditions. After ulcer healing, the limbs were placed in compressive garments and followed at 6-month intervals for ulcer recurrence. RESULTS: The mean patient age was 54.3 years, and 46% of the patients were female. Corrective venous surgery was performed in 37 limbs. The mean follow-up time for all 99 limbs was 28 months. The ulcer recurrence rate with life table was 37% +/- 6% at 3 years and 48% +/- 10% at 5 years. The patients who underwent venous surgery had a significantly lower recurrence rate (27% +/- 9% at 48 months) than did those patients who had not undergone surgery (67% +/- 8% at 48 months; P =.005). The patients with deep venous insufficiency (DVI; n = 51) had significantly higher recurrence rates (66% +/- 8% at 48 months) than did the patients without DVI (n = 48; 29% +/- 9% at 48 months; P =.006). This difference was significant even after accounting for the effects of surgery (P =.03). The hazard ratio of ulcer recurrence increases by 14% for every unit increase in the venous filling index (VFI; P =.001). This remains significant even after accounting for the effects of surgery (P =.001). The combination of DVI and a VFI of more than 4 mL/s yields a risk of ulcer recurrence of 43% +/- 9% at 1 year and 60% +/- 10% at 2 years. CONCLUSION: Leg ulcers associated with CVI have a high rate of recurrence. Ulcer recurrence is significantly increased in patients with DVI and in patients who do not have venous abnormalities corrected surgically. The VFI obtained from APG is useful in the prediction of increased risk for recurrence, particularly in association with anatomic data.

Assembly of microarrays for genome-wide measurement of DNA copy number.

We have assembled arrays of approximately 2,400 BAC clones for measurement of DNA copy number across the human genome. The arrays provide precise measurement (s.d. of log2 ratios=0.05-0.10) in cell lines and clinical material, so that we can reliably detect and quantify high-level amplifications and single-copy alterations in diploid, polyploid and heterogeneous backgrounds.

Difluoromethylornithine chemoprevention of epidermal carcinogenesis in K14-HPV16 transgenic mice.

To be informative for chemoprevention, animal models must both closely emulate human disease and possess surrogate endpoint biomarkers that facilitate rapid drug screening. This study elucidated site-specific histopathological and biochemical surrogate endpoint biomarkers of spontaneous epidermal carcinogenesis in K14-HPV16 transgenic mice and demonstrated that the incidence and severity of these markers were decreased by the ornithine decarboxylase (ODC) inhibitor difluoromethylornithine (DFMO). The cumulative incidence of visible epidermal cancers in 127 untreated transgenic mice was 42% by 52 weeks of age, most frequently affecting the chest as flat lesions in association with chronic ulcers, or in the ear as protuberant masses. Microscopic malignancies were detected in 39% of 32-week-old transgenic mice and were found to emerge from precursor lesions that were of two distinct types: dysplastic sessile ear papillomas and hyperproliferative follicular/interfollicular chest dysplasias. ODC activity and tissue polyamine contents were differentially elevated in ear and chest skin during carcinogenesis, such that there was a marked elevation of both parameters of polyamine metabolism as early as 4 weeks of age in the ear, whereas in the chest, polyamine metabolism was increased significantly only in the late stages of neoplastic progression and in epidermal cancers. Administration of 1.0% DFMO in the drinking water from 4 to 32 weeks of age prevented both visible and microscopic malignancies and significantly decreased the incidence of chest and ear precursor lesions. ODC activity and tissue putrescine content were markedly diminished by DFMO chemoprevention in ear skin, whereas there was a more modest decline of these parameters in chest skin. DFMO treatment of transgenic mice from 28 to 32 weeks of age was associated with an absence of ear cancer and a marked regression of dysplastic papillomas. In contrast, the results in chest skin were complex in that the severity of chest precursors diminished, but their incidence was unchanged, and microscopic cancers were still detectable within these lesions. Collectively, this study highlights the utility of multistage epidermal carcinogenesis in K14-HPV16 transgenic mice both for the study of the biology of, and as a screening tool for, novel drugs and chemopreventive regimens.

The stromal proteinase MMP3/stromelysin-1 promotes mammary carcinogenesis.

Matrix metalloproteinases (MMPs) are invariably upregulated in the stromal compartment of epithelial cancers and appear to promote invasion and metastasis. Here we report that phenotypically normal mammary epithelial cells with tetracycline-regulated expression of MMP3/stromelysin-1 (Str1) form epithelial glandular structures in vivo without Str1 but form invasive mesenchymal-like tumors with Str1. Once initiated, the tumors become independent of continued Str1 expression. Str1 also promotes spontaneous premalignant changes and malignant conversion in mammary glands of transgenic mice. These changes are blocked by coexpression of a TIMP1 transgene. The premalignant and malignant lesions have stereotyped genomic changes unlike those seen in other murine mammary cancer models. These data indicate that Str1 influences tumor initiation and alters neoplastic risk.

Comparison of surface-treated and untreated orthodontic bands: evaluation of shear force and surface roughness.

In an attempt to increase retention of orthodontic bands, orthodontic companies market bands with surfaces prepared to increase roughness. A comparison of six groups of bands, including two with untreated surfaces, revealed a wide range of variation in shear forces. Three classes of retention may be differentiated on the basis of non-statistically significantly different mean shear forces in each category: high (Unitek, treated), moderate (Unitek, untreated; A Co., treated; GAC, treated), and low (A Co., untreated; Dentaurum, treated). Surface roughness, as evaluated through atomic force microscopy, correlated moderately with shear force (r = 0.61; p < 0.05). This method is examined and compared with the qualitative profiles of the orthodontic band surfaces provided by optical micrography.

E2A deficiency leads to abnormalities in alphabeta T-cell development and to rapid development of T-cell lymphomas.

The E2A gene products, E12 and E47, are critical for proper early B-cell development and commitment to the B-cell lineage. Here we reveal a new role for E2A in T-lymphocyte development. Loss of E2A activity results in a partial block at the earliest stage of T-lineage development. This early T-cell phenotype precedes the development of a T-cell lymphoma which occurs between 3 and 9 months of age. The thymomas are monoclonal and highly malignant and display a cell surface phenotype similar to that of immature thymocytes. In addition, the thymomas generally express high levels of c-myc. As assayed by comparative genomic hybridization, each of the tumor populations analyzed showed a nonrandom gain of chromosome 15, which contains the c-myc gene. Taken together, the data suggest that the E2A gene products play a role early in thymocyte development that is similar to their function in B-lineage determination. Furthermore, the lack of E2A results in development of T-cell malignancies, and we propose that E2A inactivation is a common feature of a wide variety of human T-cell proliferative disorders, including those involving the E2A heterodimeric partners tal-1 and lyl-1.

Effects of electron donor and acceptor conditions on reductive dehalogenation of tetrachloromethane by Shewanella putrefaciens 200.

Shewanella putrefaciens 200 is a nonfermentative bacterium that is capable of dehalogenating tetrachloromethane to chloroform and other, unidentified products under anaerobic conditions. Since S. putrefaciens 200 can respire anaerobically by using a variety of terminal electron acceptors, including NO3-, NO2-, and Fe(III), it provides a unique opportunity to study the competitive effects of different electron acceptors on dehalogenation in a single organism. The results of batch studies showed that dehalogenation of CT by S. putrefaciens 200 was inhibited by O2, 10 mM NO3-, and 3 mM NO2-, but not by 15 mM Fe(III), 15 mM fumarate, or 15 mM trimethylamine oxide. Using measured O2, Fe(III), NO2-, and NO3- reduction rates, we developed a speculative model of electron transport to explain inhibition patterns on the basis of (i) the kinetics of electron transfer at branch points in the electron transport chain, and (ii) possible direct inhibition by nitrogen oxides. In additional experiments in which we used 20 mM lactate, 20 mM glucose, 20 mM glycerol, 20 mM pyruvate, or 20 mM formate as the electron donor, dehalogenation rates were independent of the electron donor used. The results of other experiments suggested that sufficient quantities of endogenous substrates were present to support transformation of tetrachloromethane even in the absence of an exogenous electron donor. Our results should be significant for evaluating (i) the bioremediation potential at sites contaminated with both halogenated organic compounds and nitrogen oxides, and (ii) the bioremediation potential of iron-reducing bacteria at contaminated locations containing significant amounts of iron-bearing minerals.

Suppression of interferon-gamma induction of MHC class II and ICAM-1 by a 26-base oligonucleotide composed of deoxyguanosine and deoxythymidine.

Interferon-gamma (IFN-gamma) is an important cytokine released by T lymphocytes and natural killer cells which is able to induce expression of class II MHC and ICAM-1, crucial factors in cellular immune response. HeLa S3, HS 27, and NF-71-1 are cell lines which can be induced to express HLA-DR and HLA-DP by exposure to IFN-gamma. When T2 (5'GGGGTTGGTTGTGTTGGGTGTTGTGTRNH(2)3') oligonucleotide was added at 5-20 microM every other day, cell surface induction of HLA-DR and HLA-DP by IFN-gamma was suppressed in a dose-dependent manner in HeLa S3. T2 suppressive effect on HLA class II was also observed in four different nontransformed human cell lines, HS 27 at passage 18, NF-71-1 at passage 5, human corneal endothelial cell at passage 5, and human retinal pigmented epithelial cell at passage 3. Control oligonucleotides had no suppressive effect. Northern hybridization showed that HLA-DR A mRNA induction by IFN-gamma was blocked by T2 in HeLa S3 and fibroblast 143B. The suppressive effect of T2 was also reversible as continued culture of the treated cells without further addition of the oligonucleotide allowed full re-expression of HLA-DR. Further experiments showed that T2 oligonucleotide was also able to inhibit IFN-gamma enhancement of ICAM-1 (CD54) on human corneal endothelial cell and human retinal pigmented epithelial cell. We conclude that T2 oligonucleotide is effective at suppressing HLA-DR, HLA-DP and ICAM-1 induction by IFN-gamma in transformed and nontransformed cells in vitro.

Inhibition of interferon-gamma-mediated immune functions by oligonucleotides. Suppression of human T cell proliferation by downregulation of IFN-gamma-induced ICAM-1 and Fc-receptor on accessory cells.

Recent progress in gene therapy may provide a new strategy for prevention of allograft rejection. Oligonucleotides have been shown to inhibit specific gene transcription in both cell-free and living-cell systems. In our previous studies, a 26-mer oligonucleotide (T2) designed to form a triple helix with the X/X2 box promoter region of human MHC class II (DRA) gene was shown to prevent the induction by IFN-gamma of HLA-DR molecules. Here, we show that this oligonucleotide downregulates two other IFN gamma-inducible molecules, the adhesion molecule ICAM-1 and the Fc receptor for IgG on the surface of human cells. T2 has no effect on TNF alpha- and IL-1-mediated ICAM-1 upregulation, showing its specificity for IFN gamma. T2 oligonucleotide is shown to inhibit IFN gamma-mediated induction of Fc receptor on human blood monocytes as assessed by flow cytometry. Furthermore, pretreatment of monocytes with T2 resulted in suppression of anti-CD3-mediated peripheral blood T cell proliferation. The presented data suggest that oligonucleotide T2 blockade of IFN gamma-induction of different immune receptors on accessory cells is associated with inhibition of T cell proliferative responses.

Inhibition of interferon-gamma-induced major histocompatibility complex class I expression by certain oligodeoxynucleotides.

We report that certain oligonucleotides are capable of inhibiting cell surface induction of the major histocompatibility complex class I (MHC-I) proteins by interferon-gamma in K562 cells. The inhibition by oligodeoxy-nucleotide I 5' GGG GTT GGT TGT GTT GGG TGT TGT GT-RNH2 is dose-dependent, with an EC50 24 hr after dosing of approximately 4 microM for 800 U/ml interferon-gamma. The reverse complement II 5' AC ACA ACA CCC AAC ACA ACC AAC CCC-RNH2 did not show activity. Oligodeoxynucleotide I inhibits induction of MHC-I by interferon-gamma, but does not inhibit induction by either interferon-alpha or interferon-beta. Four other oligodeoxynucleotides were also evaluated, and three showed activity against interferon-gamma at 25 microM.