Biomimetic approach for liquid encapsulation with nanofibrillar cloaks

Technologies that are able to handle microvolumes of liquids, such as microfluidics and liquid marbles, are attractive for applications that include miniaturized biological and chemical reactors, sensors, microactuators, and drug delivery systems. Inspired from natural fibrous envelopes, here, we present an innovative approach for liquid encapsulation and manipulation using electrospun nanofibers. We demonstrated the realization of non-wetting soft solids consisting of a liquid core wrapped in a hydrophobic fibrillar cloak of a fluoroacrylic copolymer and cellulose acetate. By properly controlling the wetting and mechanical properties of the fibers, we created final architectures with tunable mechanical robustness that were stable on a wide range of substrates (from paper to glass) and floated on liquid surfaces. Remarkably, the realized fiber-coated drops endured vortex mixing in a continuous oil phase at high stirring speed without bursting or water losses, favoring mixing processes inside the entrapped liquid volume. Moreover, the produced cloak can be easily functionalized by incorporating functional particles, active molecules, or drugs inside the nanofibers.

A bioartificial renal tubule device embedding human renal stem/progenitor cells

We present a bio-inspired renal microdevice that resembles the in vivo structure of a kidney proximal tubule. For the first time, a population of tubular adult renal stem/progenitor cells (ARPCs) was embedded into a microsystem to create a bioengineered renal tubule. These cells have both multipotent differentiation abilities and an extraordinary capacity for injured renal cell regeneration. Therefore, ARPCs may be considered a promising tool for promoting regenerative processes in the kidney to treat acute and chronic renal injury. Here ARPCs were grown to confluence and exposed to a laminar fluid shear stress into the chip, in order to induce a functional cell polarization. Exposing ARPCs to fluid shear stress in the chip led the aquaporin-2 transporter to localize at their apical region and the Na⁺K⁺ATPase pump at their basolateral portion, in contrast to statically cultured ARPCs. A recovery of urea and creatinine of (20±5)% and (13±5)%, respectively, was obtained by the device. The microengineered biochip here-proposed might be an innovative “lab-on-a-chip” platform to investigate in vitro ARPCs behaviour or to test drugs for therapeutic and toxicological responses.

Polymeric foams with functional nanocomposite cells

Elastomeric foams with controlled cell size and composition are formed by using calcium alginate hydrogel beads as templates.

Combined kidney and vascularized total bladder transplantation: experience in an animal model

BACKGROUND

Few reports have described a partial bladder graft with an en bloc kidney transplantation, mainly to facilitate reconstruction of the urinary tract, but also to augment the native bladder. The present study assessed the feasibility to graft vascularized total bladder in association with a renal transplantation.

METHODS

The right kidney, in continuity with the ureter and the entire bladder, was retrieved from three female pigs weighing 20 g. The visceral bloc was transplanted to three recipient pigs of the same weight. The entire bladder was transplanted with its vascular connection to ensure a better blood supply. After 3 days of observation, one recipient was humanely killed to examine the bladder graft. Oxygen saturation in the bladder graft monitored for 8 hours was compared with the native bladder in the other two recipients. All three bladder grafts were examined by a pathologist.

RESULTS

All bladder grafts seemed to be macroscopically well-perfused upon removal of the vascular clamps. In case 1, the recipient was clinically well with good urinary output over the first 2 days of observation; is contrast, on day 3 the animal displayed an acute reduced urinary output. Laparotomy on day 3 of observation showed recent thrombosis of the bladder and renal graft vessels. In cases 2 and 3, oxygen saturations of the bladder graft were normal during the 8-hour observation period, without any difference between the graft and the native bladder.

CONCLUSIONS

According to our results, vascularized total bladder transplantation is feasible. In combination with renal transplantation, it could be applied as an alternative to bladder augmentation or total bladder replacement.

Strelitzia reginae leaf as a natural template for anisotropic wetting and superhydrophobicity

Artificial surfaces that exhibit unidirectional water spreading and superhydrophobicity are obtained by Strelitzia reginae leaves. Both green and dried leaves are used, thus exploiting the plant senescence. We demonstrate that the natural drying process of the leaves strongly affects the surface morphology and wettability. Polymeric stamps from the green leaf show an arrangement of periodic microridges/microgrooves that favor anisotropic wetting, with a water contact angle (WCA) variation of about 21% along the two principal directions. Instead, the shrinkage of the leaf tissue, as a consequence of the natural dehydration process, induces an enhancement of the superficial corrugation. This results in the establishment of a superhydrophobic state, which shows a WCA of up to 160°, and water rolling off. S. reginae leaves are therefore easily accessible stamps suitable for controlling wettability and realizing surfaces that exhibit various wetting behaviors.

Biophysical properties of normal and diseased renal glomeruli

The mechanical properties of tissues and cells including renal glomeruli are important determinants of their differentiated state, function, and responses to injury but are not well characterized or understood. Understanding glomerular mechanics is important for understanding renal diseases attributable to abnormal expression or assembly of structural proteins and abnormal hemodynamics. We use atomic force microscopy (AFM) and a new technique, capillary micromechanics, to measure the elastic properties of rat glomeruli. The Young's modulus of glomeruli was 2,500 Pa, and it was reduced to 1,100 Pa by cytochalasin and latunculin, and to 1,400 Pa by blebbistatin. Cytochalasin or latrunculin reduced the F/G actin ratios of glomeruli but did not disrupt their architecture. To assess glomerular biomechanics in disease, we measured the Young's moduli of glomeruli from two mouse models of primary glomerular disease, Col4a3(-/-) mice (Alport model) and Tg26(HIV/nl) mice (HIV-associated nephropathy model), at stages where glomerular injury was minimal by histopathology. Col4a3(-/-) mice express abnormal glomerular basement membrane proteins, and Tg26(HIV/nl) mouse podocytes have multiple abnormalities in morphology, adhesion, and cytoskeletal structure. In both models, the Young's modulus of the glomeruli was reduced by 30%. We find that glomeruli have specific and quantifiable biomechanical properties that are dependent on the state of the actin cytoskeleton and nonmuscle myosins. These properties may be altered early in disease and represent an important early component of disease. This increased deformability of glomeruli could directly contribute to disease by permitting increased distension with hemodynamic force or represent a mechanically inhospitable environment for glomerular cells.

Reduction of water evaporation in polymerase chain reaction microfluidic devices based on oscillating-flow

Producing polymeric or hybrid microfluidic devices operating at high temperatures with reduced or no water evaporation is a challenge for many on-chip applications including polymerase chain reaction (PCR). We study sample evaporation in polymeric and hybrid devices, realized by glass microchannels for avoiding water diffusion toward the elastomer used for chip fabrication. The method dramatically reduces water evaporation in PCR devices that are found to exhibit optimal stability and effective operation under oscillating-flow. This approach maintains the flexibility, ease of fabrication, and low cost of disposable chips, and can be extended to other high-temperature microfluidic biochemical reactors.

Enhancement of light polarization from electrospun polymer fibers by room temperature nanoimprint lithography

We demonstrate the enhancement of the polarization ratio of light emitted from electrospun conjugated polymer nanofibers, by means of nanoimprint lithography carried out at room temperature. We provide evidence of tailoring the polarization properties by patterning light-emitting fibers at the nanoscale. The polarization ratios are increased up to a factor of 2.4 by gratings with periodicity (560 nm) matching the emission wavelength of the employed conjugated polymer. The use of room temperature nanoimprint lithography to pattern light-emitting polymer nanofibers represents a strategic route for realizing photonic crystals and distributed feedback polarized emitters on one-dimensional organic nanostructures.

Nanoparticle image velocimetry at topologically structured surfaces

Nanoparticle image velocimetry (nano-PIV), based on total internal reflection fluorescent microscopy, is very useful to investigate fluid flows within approximately 100 nm from a surface; but so far it has only been applied to flow over smooth surfaces. Here we show that it can also be applied to flow over a topologically structured surface, provided that the surface structures can be carefully configured not to disrupt the evanescent-wave illumination. We apply nano-PIV to quantify the flow velocity distribution over a polydimethylsiloxane surface, with a periodic gratinglike structure (with 215 nm height and 2 mum period) fabricated using our customized multilevel lithography method. The measured tracer displacement data are in good agreement with the computed theoretical values. These results demonstrate new possibilities to study the interactions between fluid flow and topologically structured surfaces.

Paclitaxel, ifosfamide, and cisplatin regimen as neoadjuvant chemotherapy in young women with locally advanced squamous cervical cancer

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Background: Chemoradiotherapy is the standard treatment of advanced cervical cancer. Neoadjuvant chemotherapy (NAC) may represent an alternative for locally advanced cervical cancer (LACC).This study was undertaken to evaluate the efficacy of NAC in young patients with squamous LACC. Methods: Since 2000 to 2008, 61 pts (mean age 43 yrs) with squamous LACC were treated with NAC and afterwards evaluated for radical surgery. Eligibility included proven histologically diagnosis of squamous cervical carcinoma, FIGO stage IB2/IIA>4cm/IIB, measurable disease, ECOG PS 0–2, no prior therapy and age under 49 years. All patients received TIP regimen (cisplatin 50 mg/m2 i.v. day 1, paclitaxel 175 mg/m2 over 3 hrs i.v.day1, ifosfamide 5,000 mg/m2 plus mesna 6,000 mg/m2 over 24 hrs i.v. day 1–2). Each cycle was repeated every 21 days. Patients were evaluated 4–6 weeks after the completion of the third cycle with the purpose to perform radical surgery according to clinical response. Results: 35pts (57.4%) were stage IB2; 9 (14.7%) were IIA >4cm; and 17 (27.9%) were IIB. After restaging the clinical results were: CR = 4/61 (6.6%), PR = 51/61 (83.6%); no response = 5/61 (8.2%); progression = 1/61 (1.6%). A total of 55 pts (90.1%) were eligible for surgery; 6/61 pts (9.8%) were submitted to curative radiotherapy (until 2004) or chemoradiotherapy. Pathological responses after surgery were: 4 pCR (7.3%); 46 pPR (83.6%); and 5 (9.1%) pPR with presence of positive surgical margins or metastatic lymph nodes. Out of 55 pts, 50 received 2 cycles of TIP regimen as a consolidation therapy before follow-up; 5 pts with incomplete pPR underwent radio/chemoradiotherapy. After NAC an overall downstaging of LACC was obtained in 50/61 pts (82.0%). In this group of pts at the median follow-up of 42 months (range 4–98) updated as of December 2008, the 3-years progression-free survival and overall survival are 85.9% and 82.0%, respectively. Conclusions: Our results indicate that TIP regimen-based NAC is an attractive option in young women with squamous LACC (IB2,IIA >4cm, IIB) that strongly desire surgery.The rate of patients with a prolonged remission of disease (82.0%) suggests that the clinical benefit of TIP regimen-based NAC followed by surgery may be comparable to chemoradiotherapy.

No significant financial relationships to disclose.

Patterning of light-emitting conjugated polymer nanofibres

Organic materials have revolutionized optoelectronics by their processability, flexibility and low cost, with application to light-emitting devices for full-colour screens, solar cells and lasers. Some low-dimensional organic semiconductor structures exhibit properties resembling those of inorganics, such as polarized emission and enhanced electroluminescence. One-dimensional metallic, III-V and II-VI nanostructures have also been the subject of intense investigation as building blocks for nanoelectronics and photonics. Given that one-dimensional polymer nanostructures, such as polymer nanofibres, are compatible with sub-micrometre patterning capability and electromagnetic confinement within subwavelength volumes, they can offer the benefits of organic light sources to nanoscale optics. Here we report on the optical properties of fully conjugated, electrospun polymer nanofibres. We assess their waveguiding performance and emission tuneability in the whole visible range. We demonstrate the enhancement of the fibre forward emission through imprinting periodic nanostructures using room-temperature nanoimprint lithography, and investigate the angular dispersion of differently polarized emitted light.

Patterning photo-curable light-emitting organic composites by vertical and horizontal capillarity: a general route to photonic nanostructures

We demonstrate the patterning of organic light-emitting composites made by conjugated polymers and photo-curable matrices. Using blends that exhibit both the structural properties of a low-viscosity photo-curable polymer, and the emission features of conjugated light-emitting materials, we study the operational principle of the pattern transfer and the modifications induced by the imprinting and microfluidic procedures on the optical properties of the compounds investigated. The combination of high-resolution silicone and perfluoropolyether elastomeric templates and low-viscosity, light-emitting polymeric blends offers the possibility to easily produce active organic structures with 100 nm scale resolution, thus extending current nanopatterning routes to this important class of composite material.

Ultraviolet-based bonding for perfluoropolyether low aspect-ratio microchannels and hybrid devices

Producing solvent-resistant microfluidic devices is a challenge for analytical chemistry and biochemistry. We demonstrate a simple and low-cost fabrication approach for the realization of solvent-resistant microchannels based on perfluoropolyether elastomers, exhibiting very low aspect ratios (0.01). The strength of the microchannels sealing is evaluated through the maximum internal pressure (1.52 MPa) prior to device failure, due to delamination at the bonded interface. This approach allows the elastic properties of silicone elastomers, suitable for high quality external connections, to be combined with the non-swelling character of perfluoropolyethers.

Weekly topotecan as a salvage therapy in heavily pre-treated patients with recurrent platinum-resistant epithelial ovarian cancer

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Background: The prognosis of patients with recurrent epithelial ovarian cancer is extremely poor after several lines of chemotherapy; this situation becomes more and more difficult to manage in the presence of a platinum-resistance condition. Topotecan 1.5mg/m2 on days 1 through 5 of a 21-day cycle is often employed as a second-line chemotherapy also for platinum-resistant epithelial ovarian cancer. In this phase II study we investigated the safety as well response rate of weekly topotecan as a salvage therapy in heavily pretreated patients with recurrent platinum-resistant epithelial ovarian cancer (RprEOC). Methods: To be elegible for the study patients had to be considered resistant to platinum and paclitaxel pretreated. Eleven patients (median age 51 yrs, range 45 - 70) with performance status 0–2 affected by RprEOC with measurable disease, were planned to receive weekly topotecan. They had received at least 3 prior lines of chemotherapy. Topotecan was administered at the dose of 2.0 mg/m2 via a 30-minute i.v. infusion once every week until disease progression or unacceptable toxicity. Results: All patients were evaluable for toxicity and clinical response. All the 11 pts enrolled had stage III-IV disease. Median number of chemotherapy cycles was 5 (range 3 - 8). A total of 62 cycles were administered. Dose reduction was necessary for 12% of the cycles. Main toxicities included anemia (12%), leucopenia (18%), thrombocytopenia (15%) and asthenia (20%). No deaths were attributable to therapy. No one showed complete response, while two partial response (18.2%) and four stable disease (36.4%) were observed. Five pts (45.4%) progressed on therapy. The median progression-free interval was 13 weeks. Conclusion: Salvage therapy for patients with ovarian cancer who failed several platinum and paclitaxel treatments remains a therapeutic challenge. Topotecan administered at low weekly dosage (2.0 mg/m2) is an active option in the subset of heavily RprEOC and it seems also to be a more tolerable regimen compared to the classical 5-day schedule.

No significant financial relationships to disclose.

Low-loss and highly polarized emission from planar polymer waveguides

The waveguiding properties and amplified spontaneous emission (ASE) of a blend of light-emitting gain-conjugated polymers were investigated. ASE-induced line narrowing occurs for excitation fluences larger than 100 microJ cm(-2), with a maximum optical-gain coefficient of 8 cm(-1). Energy transfer between the host and guest polymers, significantly reducing the self-absorption, leads to a loss coefficient of the waveguide as low as 0.3 cm(-1), which is believed to be the lowest value reported for active organic gain slabs and a highly polarized emission, with a polarization contrast up to 0.65. These results indicate that gain-conjugated polymer blends are state-of-the-art organic materials for lasing devices.

Very high-quality distributed Bragg reflectors for organic lasing applications by reactive electron-beam deposition

We report on the realisation of a few pairs dielectric Distributed Bragg Reflectors fabricated by reactive electron-beam deposition, with state-of-the-art performances, such as very high reflectance (up to about 99.4%), wide stop band (up to 160 nm) in the visible range, and smooth interfaces (roughness as low as 1.5 nm). As a demonstrator of the very high quality of the mirrors we realized a polymer-based vertical microcavity laser by an imprinting-like approach. The device exhibits laser action at 519 nm, indicating low-loss dielectric reflectors grown by electron-beam techniques as promising tools for organic solid-state lasers.

Photocontrolled variations in the wetting capability of photochromic polymers enhanced by surface nanostructuring

The wetting characteristics of surfaces of polymers doped with photochromic spiropyran molecules can be tuned when irradiated with laser beams of properly chosen photon energy. The hydrophilicity is enhanced upon UV laser irradiation since the embedded nonpolar spiropyran molecules convert to their polar merocyanine isomers. The process is reversed upon green laser irradiation. Structuring of the photochromic polymeric surfaces with soft lithography enhances significantly the hydrophobicity of the system, indicating that the water droplets on the patterned features interact with air that is trapped in the microcavities, thus creating superhydrophobic air-water contact areas. Furthermore, the light-induced wettability variations of the structured surfaces are enhanced by a factor of 3 compared to those on the flat surfaces. This significant enhancement is attributed to the photoinduced reversible volume changes to the imprinted gratings, which additionally contribute to the wettability changes due to the light-induced photochromic interconversions.

Optical Gain from the Open Form of a Photochromic Molecule in the Solid State

This work presents evidence for line-narrowing from the UV photoexcited open form of the photochromic molecule, indolinospiropyran (1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2'-(2H)-indole]) in the solid state. The line-narrowing is attributable to amplified spontaneous emission induced by optical gain and assisted by the waveguiding within the organic film. Optical gain throughout a band as large as 28 nm, with a maximum gain coefficient of 5.6 cm(-1), is observed in the merocyanine emission region (660-730 nm). These results open the way to the realization of hybrid devices based on the coupling between photochromic behavior and stimulated emission from conjugated molecules, such as lasing optical memories, and lasers gated by optical molecular switches.

Multilevel, room-temperature nanoimprint lithography for conjugated polymer-based photonics

We demonstrate the multilevel patterning of organic light-emitting polymers by room-temperature nanoimprint lithography (RT-NIL), which is impossible to obtain by conventional hot embossing. In particular, we realize one- and two-dimensional photonic crystals with 500 nm periodic features and investigate the changes in the optical properties (luminescence and quantum yield) of the organic active layer. An increase of the quantum yield by 2.4% for the patterned film with respect to the untextured one and the enhancement of the output light emitted at a particular angle (Theta = 69 degrees) are observed for gratings whose Bragg periodicity matched the emission wavelength of the polymer. The employment of RT-NIL to pattern polymer semiconductors without degradation of their optical properties represents a strategic route for the realization of novel nanopatterned optoelectronic devices.

Emission properties of printed organic semiconductor lasers

We investigated the emission properties of a distributed-feedback resonator based on an organic semiconductor patterned by a novel printing technology. We observed the peak splitting of the photonic bandstructure of the periodic grating and extracted the effective refractive index of the outcoupled guided modes. The laser works at the second diffraction order, exhibiting narrow single-mode emission at 637 nm, with a threshold as low as 37 microJ/cm2. The results suggest that direct printing is a promising fabrication technique for optically confined integrated optoelectronics.

Hypertension and the risk of acute myocardial infarction in Argentina. The Argentine Factores de Riesgo Coronario en America del Sur (FRICAS) Investigators

The relationship between a history of hypertension and the quality of its control in routine clinical practice and the risk of acute myocardial infarction was examined in a multicenter, case-control study conducted in Argentina between November 1991 and August 1994, within the framework of the FRICAS study. The cases were 939 patients with acute myocardial infarction and without a history of ischemic heart disease. The controls were 949 subjects identified in the same centers as the cases and admitted with a wide spectrum of acute disorders unrelated to known or suspected risk factors for acute myocardial infarction. The odds ratios and the 95% confidence intervals were derived from multiple logistic regression equations, including terms for age, gender, education, social status, exercise, smoking status, cholesterolemia, history of diabetes, body mass index, and family history of myocardial infarction. The quality of hypertension control was assessed with the most recent blood pressure reading reported by the subjects. Seventy-two percent of hypertensive cases and 62.6% of hypertensive controls had a history of antihypertensive therapy by self-report, when admitted to the medical center. The adjusted odds ratio for acute myocardial infarction due to hypertension was 2.58 (95% confidence interval, 2.08-3.19). The odds ratio was 2.42 (95% confidence interval, 1.88-3.11) when hypertensives reported that their greatest systolic value was below 200 mm Hg (moderate status) and 4.12 (95% confidence interval, 2.87-5.89) when it was above 200 mm Hg (severe status). When the highest diastolic blood pressure value was below 120 mm Hg (moderate status), the risk increased to 2.48 (95% confidence intervals, 1.90-3.24) and to 4.12 (95% confidence interval, 2.83-5.99) when it was above 120 mm Hg (severe status). If the most recent systolic blood pressure was less-than-or-equal140 mm Hg, the odds ratio was 2.59 (95% confidence interval, 1.96-3.41), and it was 3.42 (95% confidence interval, 2.40-4.87) when the value was >140 mm Hg. If the most recent diastolic blood pressure was less-than-or-equal90 mm Hg, the risk increased more than two fold (odds ratio=2.48; 95% confidence interval, 1.91-3.22), and if it was >90 mm Hg, it increased nearly four-fold (odds ratio=3.72; 95% confidence interval, 2.33-5.96). In smokers, the odds ratio was 2.28 in the absence of hypertension and increased to 7.51 when hypertension was present. In this Argentine population, hypertension is a strong and independent risk factor for acute myocardial infarction. In routine clinical practice, the control of blood pressure to levels below 140/90 seems to be required in order to reduce part (but not all) of the risk of acute myocardial infarction in hypertensive patients. (c) 2001 by CHF, Inc.

The use of high-dose-rate brachytherapy alone after lumpectomy in patients with early-stage breast cancer treated with breast-conserving therapy

PURPOSE

We present the preliminary results of our in-house protocol using outpatient high-dose-rate (HDR) brachytherapy as the sole radiation modality following lumpectomy in patients with early-stage breast cancer.

METHODS AND MATERIALS

Thirty-seven patients with 38 Stage I-II breast cancers received radiation to the lumpectomy cavity alone using an HDR interstitial implant with (192)Ir. A minimum dose of 32 Gy was delivered on an outpatient basis in 8 fractions of 4 Gy to the lumpectomy cavity plus a 1- to 2-cm margin over consecutive 4 days.

RESULTS

Median follow-up is 31 months. There has been one ipsilateral breast recurrence for a crude failure rate of 2.6% and no regional or distant failures. Wound healing was not impaired in patients undergoing an open-cavity implant. Three minor breast infections occurred, and all resolved with oral antibiotics. The cosmetic outcome was good to excellent in all patients.

CONCLUSION

In selected patients with early-stage breast cancer, treatment of the lumpectomy cavity alone with outpatient HDR brachytherapy is both technically feasible and well tolerated. Early results are encouraging, however, longer follow-up is necessary before equivalence to standard whole-breast irradiation can be established and to determine the most optimal radiation therapy technique to be employed.

Opposing functions of Ki- and Ha-Ras genes in the regulation of redox signals

Ras p21 signaling is involved in multiple aspects of growth, differentiation, and stress response [1-2]. There is evidence pointing to superoxides as relays of Ras signaling messages. Chemicals with antioxidant activity suppress Ras-induced DNA synthesis. The inhibition of Ras significantly reduces the production of superoxides by the NADPH-oxidase complex [3]. Kirsten and Harvey are nonallelic Ras cellular genes that share a high degree of structural and functional homology. The sequences of Ki- and Ha-Ras proteins are almost identical. They diverge only in the 20-amino acid hypervariable domain at the COOH termini. To date, their functions remain indistinguishable [4]. We show that Ki- and Ha-Ras genes differently regulate the redox state of the cell. Ha-Ras-expressing cells produce high levels of reactive oxygen species (ROS) by inducing the NADPH-oxidase system. Ki-Ras, on the other hand, stimulates the scavenging of ROS by activating posttranscriptionally the mitochondrial antioxidant enzyme, Mn-superoxide dismutase (Mn-SOD), via an ERK1/2-dependent pathway. Glutamic acid substitution of the four lysine residues in the polybasic stretch at the COOH terminus of Ki-Ras completely abolishes the activation of Mn-SOD, although it does not inhibit ERK1/2-induced transcription. In contrast, an alanine substitution of the cysteine of the CAAX box has very little effect on Mn-SOD activity but eliminates ERK1/2- dependent transcription.

Argentine Randomized Study: Coronary Angioplasty with Stenting versus Coronary Bypass Surgery in patients with Multiple-Vessel Disease (ERACI II): 30-day and one-year follow-up results. ERACI II Investigators

OBJECTIVE

The purpose of this study was to compare percutaneous transluminal coronary revascularization (PTCR) employing stent implantation to conventional coronary artery bypass graft surgery (CABG) in symptomatic patients with multivessel coronary artery disease.

BACKGROUND

Previous randomized studies comparing balloon angioplasty versus CABG have demonstrated equivalent safety results. However, CABG was associated with significantly fewer repeat revascularization procedures.

METHODS

A total of 2,759 patients with coronary artery disease were screened at seven clinical sites, and 450 patients were randomly assigned to undergo either PTCR (225 patients) or CABG (225 patients). Only patients with multivessel disease and indication for revascularization were enrolled.

RESULTS

Both groups had similar clinical demographics: unstable angina in 92%; 38% were older than 65 years, and 23% had a history of peripheral vascular disease. During the first 30 days, PTCR patients had lower major adverse events (death, myocardial infarction, repeat revascularization procedures and stroke) compared with CABG patients (3.6% vs. 12.3%, p = 0.002). Death occurred in 0.9% of PTCR patients versus 5.7% in CABG patients, p < 0.013, and Q myocardial infarction (MI) occurred in 0.9% PTCR versus 5.7% of CABG patients, p < 0.013. At follow-up (mean 18.5 +/- 6.4 months), survival was 96.9% in PTCR versus 92.5% in CABG, p < 0.017. Freedom from MI was also better in PTCR compared to CABG patients (97.7% vs. 93.4%, p < 0.017). Requirements for new revascularization procedures were higher in PTCR than in CABG patients (16.8% vs. 4.8%, p < 0.002).

CONCLUSIONS

In this selected high-risk group of patients with multivessel disease, PTCR with stent implantation showed better survival and freedom from MI than did conventional surgery. Repeat revascularization procedures were higher in the PTCR group.

Analysis of cadherin/catenin complexes in transformed thyroid epithelial cells: modulation by beta 1 integrin subunit

We have analysed the expression of cadherin/catenin complex molecules in PC C13 rat thyroid cells transformed in vitro with different oncogenes. No significant downregulation of either E-cadherin, alpha-, beta- and gamma-catenin was detected following the introduction of activated forms of myc, adenovirus E1A, ras, raf, myc + ras, E1A + raf. However, ras- and raf-transformed PC C13 cells showed altered adherens junctions. An altered distribution of cadherin/catenin complexes characterized by radially oriented membrane spikes perpendicular to cell edges was the most prominent feature evidenced by immunofluorescence. No beta1 integrin localization was observed in areas where this altered pattern of E-cadherin expression was detected. However, beta1 integrin subunit expression was detected at areas of cell-cell contact where E-cadherin showed a normal pattern of expression. Furthermore, ras- and raf-transformed PC C13 cells showed the ability to migrate in collagen gels, in contrast to their normal untransformed counterpart. Overexpression of beta1 integrin was found to restore normal E-cadherin localization at cell-cell contacts and to partially inhibit the ability to migrate in collagen gels. Finally, two cell lines obtained by ras transformation in vivo, and derived from a rat primary thyroid carcinoma (TK6) and its lung metastasis (MPTK6), were found to have lost gamma-catenin expression. TK6 lost also E-cadherin expression and membrane localization of alpha-catenin. These results suggest that: i) in vitro thyroid cell transformation is associated to a change in cadherin/catenin complexes distribution rather than to a decrease in expression; ii) in vivo transformation is associated to the loss of expression of some of these molecules likely due to tumor progression; iii) alterations in beta1 integrin subunit expression can result in changes in cadherin/catenin function thus implying that an integrin-cadherin synergy may exist in thyroid cells.

[Moderating action of celiac block in experimental pancreatitis in the dog]

BACKGROUND

Pancreatic ischemia seems to be responsible of transition from edematous to hemorrhagic forms in acute pancreatitis. (AP) Sympathetic system vasoconstriction, through celiac plexus play an important role in the pathogenesis of acute pancreatitis.

OBJECTIVE

Determinate the effects of anesthetic celiac blockade in an experimental model of AP.

METHODS

Distal pancreatectomy and intraductal injection of autologous bile in 28 mongrel dogs. Blockade of celiac plexus with bupivacaine in the experimental group B. Anatomopathologic examination after 72 hours.

RESULTS

Experimental group B developed milder forms of AP, while the control group A developed severe forms.

CONCLUSIONS

Results suggest that celiac plexus blockade with bupivacaine may prevent the development of necrohemorrhagic forms of PA in a canine model.

The localization and activity of cAMP-dependent protein kinase affect cell cycle progression in thyroid cells

cAMP signals are received and transmitted by multiple isoforms of cAMP-dependent protein kinases (PKAs), typically determined by their specific regulatory subunits. We describe changes in the cAMP signal transduction pathway during cell cycle progression in synchronized rat thyroid cells. Both PKA type II (PKAII) localization and nuclear cAMP signaling are significantly modified during G(0) and G(1)-S transitions. G(1) is characterized by PKA activation and amplified cAMP signal transduction. This is associated with a decrease in the concentration of RI and RII regulatory subunits and enhanced anchoring of PKAII to the Golgi-centrosome region. Just prior to S, the cAMP pathway is depressed. Up-regulation of the pathway by exogenous cAMP in G(1) inhibited the subsequent decay of the Cdk inhibitor p27 and delayed the onset of S phase. Forced translocation of endogenous PKAII to the cytosol down-regulated cAMP signaling, advancing the timing of p27 decay and inducing premature exit from G(1). These data indicate that membrane-bound PKA amplifies the transduction of cAMP signals in G(1) and that the length of G(1) is influenced by cAMP-PKA.

Iridium-192 transperineal interstitial brachytherapy for locally advanced or recurrent gynecological malignancies

PURPOSE

To assess treatment outcome for patients with locally advanced or recurrent gynecological malignancies treated with continuous low-dose-rate (LDR) remote afterloading brachytherapy using the Martinez Universal Perineal Interstitial Template (MUPIT).

MATERIALS AND METHODS

Between 7/85 and 6/94, 69 patients with either locally advanced or recurrent malignancies of the cervix, endometrium, vagina, or female urethra were treated by 5 different physicians using the MUPIT with (24 patients) or without (45 patients) interstitial hyperthermia. Fifty-four patients had no prior treatment with radiation and received a combination of external beam irradiation (EBRT) and an interstitial implant. The combined median dose was 71 Gy (range 56-99 Gy), median EBRT dose was 39 Gy (range 30-74 Gy), and the median implant dose was 32 Gy (range 17-40 Gy). Fifteen patients with prior radiation treatment received an implant alone. The total median dose including previous EBRT was 91 Gy (range 70-130 Gy) and the median implant dose was 35 Gy (range 25-55 Gy).

RESULTS

With a median follow-up of 4.7 yr in survivors, the 3-yr actuarial local control (LC), disease-specific survival (DSS), and overall survival (OS) for all patients was 60%, 55%, and 41% respectively. The clinical complete response rate was 78% and in these patients the 3-year actuarial LC, DSS, and OS was 78%, 79%, and 63% respectively. On univariate analysis for local control, disease volume and hemoglobin were found to be statistically significant. On multivariate analysis, however, only disease volume remained significant (p = 0.011). There was no statistically significant difference in local control whether patients had received any prior treatment with radiation (p = 0.34), had recurrent disease (p = 0.13), or which physician performed the implant (p = 0.45). The grade 4 complication rate (small bowel obstruction requiring surgery, fistulas, soft tissue necrosis) for all patients was 14%. With a dose rate less than 70 cGy/hour, the grade 4 complication rate was 3% vs. 24% with dose rate > or = 70 cGy/hour (p = 0.013).

CONCLUSION

Patients with locally advanced or recurrent gynecological malignancies treated with the remote afterloader LDR MUPIT applicator can expect reasonable rates of local control that are not operator-dependent. Complication rates with this approach are acceptable and appear to be related to the dose rate.

Clinical predictors of in-hospital prognosis in unstable angina: ECLA 3. The ECLA Collaborative Group

OBJECTIVES

Because of recent changes in the treatment of unstable angina, we wanted to reassess the short-term prognostic value of clinical and echocardiographic variables.

METHODS

This was an observational, prospective study that included 1038 nonselected consecutive patients admitted to coronary care units for unstable angina.

RESULTS

Baseline characteristics were age 60.18 +/- 16 years, history of prior myocardial infarction in 336 patients (32%), and a history of previous angina in 817 patients (78.7%). Angina during the 48 hours before admission was observed in 1004 patients (96.7%) and ST-segment changes on admission electrocardiogram occurred in 385 patients (37%). In-hospital treatment consisted of nitrates in 81.4% of patients, aspirin in 88.6%, beta-blockers in 71%, intravenous heparin in 34.5%, subcutaneous heparin in 23%, and angioplasty or coronary artery bypass grafting in 25.1%. After admission, angina occurred in 443 patients (40.8%), refractory angina in 223 patients (21.5%), and death or myocardial infarction in 84 patients (8.1%). At admission, the independent predictors of myocardial infarction or death identified by multivariate logistic regression analysis were ST-segment depression (odds ratio [OR] 2.13, 95% confidence interval [CI] 1.23 to 3.68, P =.006), prior angina (OR 2.23, 95% CI 0.98 to 5.05, P =.05), number of episodes of angina within the previous 48 hours (OR 1.63, 95% CI 0.98 to 2.70, P =.05), and history of smoking (OR 0.69, 95% CI 0.56 to 0.85, P =.004). Age greater than 65 years (OR 1.49, 95% CI1.09 to 2.03, P = 0.03) was significantly related to in-hospital death. The area under the receiver operating characteristic curve for application of this model was 0.59. Sensitivity was 80% with a specificity of only 33%. Refractory angina after admission showed a strong relation with an adverse short-term outcome.

CONCLUSIONS

With current therapy, clinical and electrocardiographic variables provide useful information about the short-term outcome of unstable angina. However, this model has low specificity to identify high-risk patients. Future studies about the incremental value of the new serum markers such as troponin T and C-reactive protein to assist in identification of high-risk patients are necessary.

In-hospital and late results of coronary stents versus conventional balloon angioplasty in acute myocardial infarction (GRAMI trial). Gianturco-Roubin in Acute Myocardial Infarction

One hundred four patients presenting with acute myocardial infarction < 24 hours after onset were randomized to 2 groups: group I (n = 52) was treated with balloon angioplasty followed electively with Gianturco Roubin II stents, and group II was treated with conventional balloon angioplasty alone (n = 52). All lesions were suitable for stenting. Baseline clinical, demographic, and angiographic characteristics were similar in the 2 groups. Procedural success was defined as no laboratory death or emergent coronary bypass, Thrombolysis In Myocardial Infarction (TIMI) trial 2 or 3 flow after the procedure in a culprit vessel, and a residual stenosis < or = 30% for coronary angioplasty and < 20% for stent. Procedural success was 98% in group I versus 94.2% in group II, p = NS. Thirteen patients in group II (25%) had bailout stenting during the initial procedure. Adverse in-hospital events including either death, nonelective coronary bypass, recurrent ischemia, and reinfarction occurred in 3.8% in group I versus 19.2% in group II, p = 0.03. Repeat angiography performed routinely before hospital discharge revealed TIMI 3 flow in the infarct-related artery in 98% in group I versus 83% in group II, p < 0.03. At late follow-up, event-free survival was significantly better in the stent (83%) than in the coronary angioplasty (65%) group (p = 0.002). The procedural in-hospital and late outcomes of this randomized study demonstrate that balloon angioplasty followed electively by coronary stents can be used as the primary modality for patients undergoing coronary interventions for acute myocardial infarction, increasing TIMI 3 flow, reducing in-hospital adverse events, and improving late outcome compared with balloon angioplasty alone.

Spatial reproducibility of the ring and tandem high-dose rate cervix applicator

PURPOSE

High-dose rate (HDR) applicators for uterine cervix brachytherapy are used with increasing frequency. Because multiple HDR fractions are required for treatment, the applicator position reproducibility is of most importance. To study this effect, the clinical data from patients with uterine cervix cancer were examined retrospectively to evaluate the interfraction geometric variation of the HDR applicator and its potential treatment impact.

METHODS AND MATERIALS

Eighteen patients with invasive cervical cancer who were treated with definitive radiotherapy at William Beaumont Hospital were included in the study. Patients were treated with 45-50.4 Gy megavoltage external beam to the pelvis, and 35 Gy to the prescription point A from 7 fractions of HDR brachytherapy. The 3-dimensional (3D) interfraction geometrical variation of the ring and tandem (R & T) applicator was measured using predefined reference points in the 7 sets of orthogonal simulation films obtained prior to each HDR application. Spatial reproducibility of the R & T insertion and time-trend of the R & T position variation related to patient's anatomy during the treatment course were analyzed with respect to different groups of patients who had either early or advanced disease.

RESULTS

The translational variation of the applicator position for all patients was 6.5, 5.9, and 7.7 mm (one standard deviation), respectively, in the patient's superior-to-inferior (SI), right-to-left lateral (RL), and anterior-to-posterior (AP) direction. The rotational variation was 3.4, 4.6, and 6.0 degrees (one standard deviation) in the patient's coronal, transverse, and sagittal planes. When the patients were grouped based on early disease or advanced disease, the latter demonstrated substantially larger variation (factor of 2) in the applicator position than the former. Furthermore, the time-trend of position variation was observable for both groups of patients. The variations occurred primarily during the first 3 fractions.

CONCLUSIONS

Based on the good spatial reproducibility observed in our study, the current clinical procedure for the HDR R & T applicator placement is reliable. Positional reproducibility of the R & T applicator is highly dependent upon the size of tumor volume, which, in turn, deviates the applicator during the early course of HDR brachytherapy. Attention to the construction of the midline block is of paramount importance.

The use of ultrasonography in the localization of the lumpectomy cavity for interstitial brachytherapy of the breast

PURPOSE

To determine the value of breast ultrasonography (US) in defining the lumpectomy cavity for patients treated with interstitial brachytherapy.

METHODS AND MATERIALS

In March 1993, a protocol of low dose rate (LDR) interstitial brachytherapy as the sole radiation modality in selected patients with early breast cancer was initiated at William Beaumont Hospital. To date, 60 patients have been entered in this protocol, and 38 have undergone US assisted placement of interstitial brachytherapy needles. The lumpectomy cavity was outlined in all dimensions and corresponding skin marks were placed for reference at time of implantation. These US dimensions were compared to the physician's clinical estimate of the location of the lumpectomy cavity, the patient's presurgical mammogram, and the position of the surgical scar. In the intraoperative setting, the dimensions of the lumpectomy cavity were also obtained and the placement of the deep plane of interstitial needles was verified by US.

RESULTS

The full extent of the lumpectomy cavity was underestimated by clinical examination (physical exam, operative report, mammographic information and location of the surgical scar) in 33 of 38 patients (87%). The depth to the chest wall was also incorrectly estimated in 34 (90%) patients when compared to US examination. Intraoperatively, US was performed in nine patients and was useful in verifying the accurate placement of the deepest plane of interstitial brachytherapy needles. In 7 of 9 patients (75%), clinical placement of needles did not ensure adequate coverage of the posterior extent of the lumpectomy cavity as visualized by intraoperative US.

CONCLUSIONS

In breast cancer patients considered for interstitial brachytherapy, US appears to be a more accurate means of identifying the full extent of the lumpectomy cavity when compared to clinical estimates. In addition, US allows real-time verification of needle placement in the intraoperative setting.

Amrinone stimulation test: ability to predict improvement in left ventricular ejection fraction after coronary bypass surgery in patients with poor baseline left ventricular function

OBJECTIVES

This study sought to determine whether the response to amrinone in patients with severe baseline left ventricular dysfunction can predict improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

BACKGROUND

Previous studies have suggested that the inotropic response to dobutamine can identify viable myocardium in the setting of chronic coronary disease and left ventricular dysfunction. However, increased oxygen demand stimulated by dobutamine can lead to superimposition of ischemia on the hibernating state, potentially confounding interpretation of results. Amrinone is an inotropic agent that does not critically augment myocardial oxygen demand and may be useful for identification of hibernating myocardium in the chronically ischemic state.

METHODS

Forty-four consecutive patients with coronary artery disease and left ventricular ejection fraction < 40% referred for coronary artery bypass graft surgery underwent amrinone stimulation (1 mg/kg body weight). Left ventricular ejection fraction was determined before amrinone stimulation, 20 min after infusion and 21 days after bypass surgery.

RESULTS

Baseline ejection fraction was 28 +/- 7% (mean +/- SD). Ejection fraction increased to 35 +/- 5% after amrinone stimulation (p < 0.0001) and to 33 +/- 6% after bypass surgery (p < 0.0001). Postbypass ejection fraction was significantly correlated with postamrinone ejection fraction (r = 0.65, p < 0.0001). Furthermore, the change in ejection fraction from baseline to after bypass surgery was highly correlated with the change in ejection fraction after amrinone stimulation (r = 0.75, p < 0.0001). Of 13 patients with an increase in ejection fraction > or = 10% after amrinone, all 13 had an increase of at least 8% and 11 (85%) of 13 had an increase > or = 10% after bypass surgery. In contrast, of 31 patients with an increase in ejection fraction < 10% after amrinone, only 2 (6%) had an increase > or = 10% (p < 0.0001) and 28 (90%) of 31 had an increase < 5% after bypass surgery.

CONCLUSIONS

Augmentation of myocardial contraction by amrinone in patients with chronic coronary artery disease and severe baseline left ventricular dysfunction predicts improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

The v-Ki-Ras oncogene alters cAMP nuclear signaling by regulating the location and the expression of cAMP-dependent protein kinase IIbeta

The v-Ki-Ras oncoprotein dedifferentiates thyroid cells and inhibits nuclear accumulation of the catalytic subunit of cAMP-dependent protein kinase. After activation of v-Ras or protein kinase C, the regulatory subunit of type II protein kinase A, RIIbeta, translocates from the membranes to the cytosol. RIIbeta mRNA and protein were eventually depleted. These effects were mimicked by expressing AKAP45, a truncated version of the RII anchor protein, AKAP75. Because AKAP45 lacks membrane targeting domains, it induces the translocation of PKAII to the cytoplasm. Expression of AKAP45 markedly decreased thyroglobulin mRNA levels and inhibited accumulation of C-PKA in the nucleus. Our results suggest that: 1) The localization of PKAII influences cAMP signaling to the nucleus; 2) Ras alters the localization and the expression of PKAII; 3) Translocation of PKAII to the cytoplasm reduces nuclear C-PKA accumulation, resulting in decreased expression of cAMP-dependent genes, including RIIbeta, TSH receptor, and thyroglobulin. The loss of RIIbeta permanently down-regulates thyroid-specific gene expression.

The v-erbA oncogene selectively inhibits iodide uptake in rat thyroid cells

v-erbA is the oncogenic form of the c-erbA proto-oncogene, which encodes the receptor for thyroid hormones. The expression of the v-erbA oncogene in thyroid differentiated cells, PC Cl 3, inhibits iodide uptake and thyrotropin-dependent growth, whereas it has no effect on the expression of the other thyroid specific markers, i.e. thyroglobulin, thyroperoxidase and thyrotropin receptor. The activity of transcription factor AP-1, evaluated by a specific DNA binding assay and by transcription of AP-induced promoter (TRE) is enhanced in PC v-erbA cells. v-erbA mutants in the DNA binding domain do not affect the iodide uptake of thyroid cells nor AP-1 activity. We suggest that this transcriptional activation mediates the selective effects of v-erbA on the expression of thyroid specific markers.

The differential response of protein kinase A to cyclic AMP in discrete brain areas correlates with the abundance of regulatory subunit II

We analyzed the expression and relative distribution of mRNA for the regulatory subunits (RIalpha, RIIalpha, and RIIbeta) and of 150-kDa RIIbeta-anchor proteins for cyclic AMP (cAMP)-dependent protein kinase (PKA) into discrete brain regions. The subcellular distribution of both holoenzyme and free catalytic subunit was evaluated in the same CNS areas. In the neocortex and corpus striatum high levels of RIIbeta paralleled the presence of specific RII-anchoring proteins, high levels of membrane-bound PKA holoenzyme, and low levels of cytosolic free catalytic activity (C-PKA). Conversely, in brain areas showing low RIIbeta levels (cerebellum, hypothalamus, and brainstem) we found an absence of RII-anchoring proteins, low levels of membrane-bound holoenzyme PKA, and high levels of cytosolic dissociated C-PKA. Response to cAMP stimuli was specifically evaluated in the neocortex and cerebellum, prototypic areas of the two different patterns of PKA distribution. We found that cerebellar holoenzyme PKA was highly sensitive to cAMP-induced dissociation, without, however, a consistent translocation of C-PKA into the nucleus. In contrast, in the neocortex holoenzyme PKA was mainly in the undissociated state and poorly sensitive to cAMP. In nuclei of cortical cells cAMP stimulated the import of C-PKA and phosphorylation of cAMP-responsive element binding protein. Taken together, these data suggest that RIIbeta (whose distribution is graded throughout the CNS, reaching maximal expression in the neocortex) may represent the molecular cue of the differential nuclear response to cAMP in different brain areas, by controlling cAMP-induced holoenzyme PKA dissociation and nuclear accumulation of catalytic subunits.

Three-year follow-up of the Argentine Randomized Trial of Percutaneous Transluminal Coronary Angioplasty Versus Coronary Artery Bypass Surgery in Multivessel Disease (ERACI)

OBJECTIVES

The purpose of this study was to report the 3-year follow-up results of the ERACI trial (Argentine Randomized Trial of Percutaneous Transluminal Coronary Angioplasty Versus Coronary Artery Bypass Surgery in Multivessel Disease).

BACKGROUND

Although coronary angioplasty has been used with increased frequency in patients with multivessel coronary artery disease, its value, compared with bypass graft surgery, has not been established. Thus, controlled, randomized clinical trials such as the ERACI are needed.

METHODS

In this trial 127 patients who had multivessel coronary artery disease and clinical indication of myocardial revascularization were randomized to undergo coronary angioplasty (n = 63) or bypass surgery (n = 64). The primary end point of this study was event-free survival (survival with freedom from myocardial infarction, angina and new revascularization procedures) for both groups of patients at 1, 3 and 5 years of follow-up.

RESULTS

Freedom from combined cardiac events (death, Q-wave myocardial infarction, angina and repeat revascularization procedures) was significantly greater for the bypass surgery group than the coronary angioplasty group (77% vs. 47%; p < 0.001). There were no differences in overall (4.7% vs. 9.5%; p = 0.5) and cardiac (4.7% vs. 4.7%; p = 1) mortality or in the frequency of myocardial infarction (7.8% vs. 7.8%; p = 0.8) between the two groups. However, patients who had bypass surgery were more frequently free of angina (79% vs. 57%; p < 0.001) and required fewer additional reinterventions (6.3% vs. 37%; p < 0.001) than patients who had coronary angioplasty.

CONCLUSIONS

1) Freedom from combined cardiac events at 3-year follow-up was greater in patients who had bypass surgery than in those who had coronary angioplasty. 2) The coronary angioplasty group had a higher incidence of recurrence of angina and the need for repeat revascularization procedures. 3) Cumulative cost at 3-year follow-up was greater for the bypass surgery group than for the coronary angioplasty group.

Inhibition of cellular ras prevents smooth muscle cell proliferation after vascular injury in vivo

Proliferation of smooth muscle cells of the arterial wall in response to local injury is an important aetiologic factor of vascular proliferative disorders such as atherosclerosis and restenosis after angioplasty. Ras proteins are key transducers of mitogenic signals from membrane to nucleus in many cell types. We investigated the role of ras proteins in the vascular response to arterial injury by inactivating cellular ras of rats in which the common carotid artery was subjected to balloon injury. DNA vectors expressing ras transdominant negative mutants, which interfere with ras function, reduced neointimal formation after injury. Our results indicate a key role for ras in smooth muscle cell proliferation and show that the local delivery of transdominant negative mutants of ras in vivo might prevent some of the acute vascular injury caused by balloon injury.