Comparison of endoscopic laser therapy and self expanding metal stents for palliation in patients with non-resectable oesophageal carcinoma.

BACKGROUND: There are currently limited data on the comparative success of endoscopic laser therapy (NLT) and self expanding metal stents (SEMS) as palliative measures in patients with non-resectable oesophageal cancer. This study aims to assess and compare the outcomes of these methods of endoscopic palliation. METHODS: Patients with non-curative oesophageal/gastro-oesophageal cancers with dysphagia were identified prospectively and consented to swallow assessment and follow-up. Patients underwent SEMS or NLT at the discretion of the treating endoscopist. Initial standardised swallow scores (0-4) were assessed. All subsequent interventions were recorded as well as survival. RESULTS: 31 patients were recruited (30M vs 8F, mean age 70.8). There was no significant difference in age, sex or chemotherapy treatment between groups. 19(61%)patients underwent NLT as primary procedure. 20(64.5%) patients required subsequent intervention(s) (median 1, range 0-8). Primary NLT patients were more likely to require subsequent therapy (p = 0.004) and multiple procedures (p = 0.001). 8(42.1%)patients initially undergoing NLT subsequently required SEMS, while no SEMS patients underwent subsequent NLT. Swallow scores of 1 or 2 were more likely to be maintained with NLT while scores of 3 or 4 were more likely to progress to SEMS (p = 0.039). Time to repeat procedure was greater in the SEMS group (p = 0.001). Median survival was 133 days for NLT vs 60 days for SEMS (p = 0.412). CONCLUSION: In this series, patients selected for NLT had a trend towards longer survival, but were more likely to require repeated procedures. Those with lower early initial dysphagia scores were more likely to be maintained by NLT alone.

Intraoperative retrograde mesenteric angioplasty for acute occlusive mesenteric ischaemia: a case series.

Acute mesenteric ischaemia secondary to atherosclerotic disease of the superior mesenteric artery is a surgical emergency associated with a poor prognosis, and requires prompt diagnosis and early revascularisation in order to improve outcome. The traditional management of surgical resection of necrotic bowel plus mesenteric revascularisation by surgical bypass is associated with significant morbidity and mortality. We describe the use of a combined surgical and endovascular approach, using intraoperative retrograde superior mesenteric angioplasty at the time of laparotomy. Four patients have been treated by this combined technique with three surviving, although one subsequently required an open surgical revascularisation procedure.

The value of an elastic tissue stain in detecting venous invasion in colorectal cancer.

BACKGROUND: Venous invasion by tumour is an independent prognostic indicator of both prognosis and risk of development of distant metastases in colorectal carcinoma. The use of special stains to aid its detection in pathology specimens is not currently universally recommended. AIMS: To determine whether an elastica stain significantly increases the incidence of detection of vascular invasion compared with routinely stained sections. METHODS: Serial sections from the 75 cases of colorectal carcinoma were stained by haematoxylin and eosin (H&E) only and elastica counterstained with H&E. The incidence of both intramural and extramural venous invasion was recorded and compared with that seen when the tumours were originally reported. RESULTS: Extramural venous invasion had been noted in 14 of the pathology reports and was seen in 18 cases when only the H&E sections were viewed in the study. It was present in 32 cases when elastica stained sections were analysed. Intramural venous invasion was seen in eight cases on H&E sections and 30 cases on elastica stained sections. CONCLUSION: The use of elastica stained serial sections to detect venous invasion in tumours should be recommended in guidelines for the reporting of colorectal carcinomas.

Depletion of cells of monocyte lineage prevents loss of renal microvasculature in murine kidney transplantation.

BACKGROUND: Acute rejection increases the risk of late renal allograft loss with tubular atrophy, interstitial fibrosis, and microvascular rarefaction. Evidence supports a role for macrophages in promoting allograft injury, but the pathogenic mechanisms are unclear. Using a model of acute rejection, we sought evidence of macrophage-mediated endothelial cell cytotoxicity leading to loss of the renal microvasculature. METHODS: We used a transgenic conditional ablation strategy to deplete circulating monocytes and infiltrating renal macrophages after kidney transplantation. CD11b-DTR mice (FVB/nj strain) are transgenic for the human diphtheria toxin receptor gene under the control of the CD11b promoter. Administration of diphtheria toxin results in rapid ablation of circulating monocytes and resident/infiltrating renal macrophages. Transplants were performed between fully mismatched strains (Balb/c donor into control nontransgenic FVB/nj recipient; allograft group), between FVB/nj littermates (isograft group), and from Balb/c donors into CD11b-DTR mice (DT-treated group). Diphtheria toxin was administered at days 3 and 5, and the effect of monocyte/macrophage depletion on changes in renal microvasculature was determined at day 7. RESULTS: Conditional monocyte and macrophage ablation effectively depleted infiltrating macrophages in murine renal allografts at day 7. Macrophage ablation reduced histologic features of rejection (arteritis, tubulitis) and the accompanying rarefaction of peritubular capillaries at 7 days. The identification of macrophages immunopositive for inducible nitric oxide synthase implicated nitric oxide generation as a possible mechanism of endothelial cell cytotoxicity. CONCLUSION: These data indicate a significant role for macrophages in causing acute rejection-related tissue injury that is, at least in part, targeted to the microcirculation.

Fast surface profiling by spectral analysis of white-light interferograms with fourier transform spectroscopy.

We present a fast white-light interference method for measuring surface depth profiles at nanometer scales. Previously reported white-light profilers have relied either on path difference scanning or on spectral analysis of the reflection from a fixed interferometer. We show that by performing this spectral analysis with an imaging Fourier transform spectrometer, the high speed of spectral techniques may be combined with the simple data interpretation characteristic of the scanning method. Giving experimental results from a profiler based on this principle, we show that real-time visualization of surface profiles is possible and we report measurements with a repeatability of approximately 5 nm rms. We also demonstrate good agreement with stylus profiler measurements.

Development of a spatial light modulator: a randomly addressed liquid-crystal-over-nMOS array.

The construction of a 50- x 50-pixel spatial light modulator based on an active silicon backplane and using the hybrid field effect in nematic liquid crystals as the light modulating process is described. The design and electrical evaluation of the pixel array, which is fabricated in 1.5-microm nMOS and has an individual memory cell within each pixel, are discussed. The performances of a 16 x 16 prototype SLM and the new 50- x 50-pixel device are compared to provide an indication of progress toward high performance spatial light modulators with onboard pixel memory.

Time-multiplexed optical Hadamard image transforms with ferroelectric-liquid-crystal-over-silicon spatial light modulators.

The Hadamard transform is an example of a matrix transform that allows images to be represented in terms of orthogonal basis functions with binary-valued matrix elements. Such basis functions can be displayed on binary amplitude modulating ferroelectric-liquid-crystal-over-silicon spatial light modulators, permitting novel, real-time, and high-speed implementation of the transform on incoherently illuminated input scenes. An example of an optical Hadamard transform performed in real time by using a spatial light modulator is described. To show the validity of this optical decomposition, we electronically reconstruct the transformation data for comparison with the original input scene.

Mirror quality and efficiency improvements of reflective spatial light modulators by the use of dielectric coatings and chemical-mechanical polishing.

To date, silicon backplane spatial light modulators have been characterized by poor-quality mirrors. Hillock formation during metal sintering has been identified as the source of this problem. Here hillock elimination is achieved by constraining the metal with a low-temperature plasma-enhanced chemicalvapor deposition silicon dioxide coating. A double-layer metallization procedure increases the silicon area available for circuitry and improves the mirror fill factor. Second-layer metal mirrors require a flat, intermediate dielectric substrate. Chemical-mechanical polishing is demonstrated to provide the flatness necessary to achieve high optical quality.

Real-time binary phase holograms on a reflective ferroelectric liquid-crystal spatial light modulator.

A ferroelectric liquid-crystal spatial light modulator with an active silicon backplane is used to implement reconfigurable reflective phase holograms. Optical results are presented for an optimized computergenerated Fourier hologram.

Evolutionary development of advanced liquid crystal spatial light modulators.

Taking into account recent developments and present trends in devices and component technologies, the future development of electrically addressed liquid crystal spatial light modulators is considered. In particular, the combination of single-crystal-silicon active backplane and chiral smectic C liquid crystal technologies is shown to be promising. The ultimate limitations of such technologies for producing faster devices of higher complexity and functionality are assessed, and an advanced device, presently under development, is described.

Improving the performance of liquid-crystal-over-silicon spatial light modulators: issues and achievements.

The performance of liquid-crystal-over-silicon spatial light modulators has advanced rapidly in recent years. Most progress has centered around new device designs with increased bandwidth. In this paper we report on a number of techniques to improve the optical quality; these have applications in both current and future devices.

Measurements on ferroelectric liquid-crystal spatial light modulators: contrast ratio and speed.

The contrast ratio and the speed of a 16 × 16 electrically addressed spatial light modulator, composed of a ferroelectric liquid-crystal layer on top of a VLSI silicon backplane, are measured with different methods but consistent results. The results are presented and compared with recently reported results on a similar spatial light modulator [Appl. Opt. 33, 2775 (1994)].