Time-resolved thermally induced aberrations in a flash-lamp pumped Nd:Glass disk amplifier using a 2 × 2 position sensitive detector array

A novel technique of measuring the prompt, thermally induced wave-front aberrations in a large aperture flash-lamp pumped Nd³⁺ glass disk amplifier is presented. Implementing a 2 × 2 lens array and a 2 × 2 position sensitive detector array as a diagnostic system, the wave-front profile was successfully reconstructed for the first five Zernike terms for a temporal window of 8.5 ms.

Towards the Optical Detection of Field Cancerization in the Buccal Mucosa of Patients with Lung Cancer

INTRODUCTION: An increase in detection of early-stage asymptomatic lung tumors could increase the overall survival rate of lung cancer patients. A new approach to cancer (pre-)screening focusses on detecting field cancerization instead of the tumor itself. The objective of this study was to investigate the use of optical spectroscopy to detect field cancerization in the buccal mucosa of lung cancer patients. METHODS: Optical buccal mucosa measurements were performed in lung cancer patients and controls using multidiameter single-fiber reflectance spectroscopy. We analyzed whether the measured optical parameters could distinguish lung cancer patients from controls. RESULTS: Twenty-three lung cancer patients, 24 chronic obstructive pulmonary disease (COPD) control patients, and 36 non-COPD controls were included. The majority of tumors were non-small-cell lung carcinomas (96%) and classified as stage I (48%). The tissue scattering properties μ_s' and γ at 800 nm and the tissue bilirubin concentration were all near-significantly different (P = .072, 0.058, and 0.060, respectively) between the lung cancer and COPD group. μ_s' at 800 nm had a sensitivity of 74% and a specificity of 63%. The microvascular blood oxygen saturation of the lung cancer patients was also higher than the COPD patients (78% vs. 62%, P = .002), this is probably a consequence of the systemic effect of COPD. CONCLUSIONS: We have demonstrated that μ_s' at 800 nm is increased in the buccal mucosa of patients with lung cancer compared to controls with COPD. This might be an indication of field cancerization in the oral cavity of patients with lung cancer.

Ultrasound Determination of the Femoral Head-Neck Alpha Angle

The femoral head-neck alpha angle is used to quantify the degree of femoral head asphericity in patients suspected of cam-type femoroacetabular impingement. The measurement was first performed using magnetic resonance imaging and, more recently, three-dimensional computed tomography (CT). We set out to determine whether the alpha angle could be reliably measured using ultrasound. Patients were recruited from a cohort presenting for CT of the hip. Alpha angles were calculated following the departmental protocol by institutionally accredited radiographers. After the CT, patients were imaged with ultrasound and the alpha angle calculated from the ultrasound image by a sonographer blinded to the CT result. Statistical comparison of the two methods was performed with the Bland-Altman test using SPSS (version 21.0, Chicago, USA), and a p < 0.05 afforded significance. Twenty-eight patients were recruited. Eleven patients were bilateral examinations, providing 39 hips for analysis. There were 15 females and 13 males, with 21 right and 18 left hips examined. Average patient age (±standard deviation) was 40 y (±13.9 y). Mean (±standard deviation) measurements for CT and ultrasound were 62.5° (±14.2°) and 64.5° (±12.6°), respectively. The mean absolute difference between the two methods was 10.5° (95% confidence interval 6.9°-14.0°). Sensitivity of each individual ultrasound measurement was 91.3%. The specificity of ultrasound was 43.75%. The positive predictive value was 0.7, and the negative predictive value was 0.78. Overall accuracy of the ultrasound-derived alpha angle was calculated at 0.718. Ultrasound demonstrates good sensitivity and good negative predictive value in calculation of the femoral head-neck alpha angle compared with CT; however, specificity is low. Ultrasound measurement of the alpha angle can provide objective evidence of cam-type femoroacetabular impingement in symptomatic patients and can direct patients to more established imaging techniques where appropriate.

Abstract P4-01-01: Phase II in-human dose escalation study of the optical molecular imaging tracer bevacizumab-800cw for molecular fluorescence guided surgery in primary breast cancer patients

Introduction

Molecular Fluorescence Guided Surgery (MFGS) might be used for intraoperative detection of positive resection margins in breast conserving surgery (BCS) for the treatment of breast cancer. Currently, the presence of tumor positive resection margins can only be assessed ex vivo by histopathological analysis of the excised tissue, which takes up to 5 working days. The current study defined the optimal dose of the near-infrared (NIR) optical imaging tracer bevacizumab-800CW to enable intraoperative detection and image-guided pathology of tumor positive resection margins in breast cancer patients.

Methods

Molecular Fluorescence Guided Surgery during BCS was performed in subjects treated for primary breast cancer. The NIR optical imaging tracer bevacizumab-800CW targeting vascular endothelial growth factor A was administered intravenously three days prior to surgery in four escalating dose groups (4.5mg, 10mg, 25mg and 50mg). NIR fluorescent signals were detected real-time using an intraoperative fluorescence camera system (SurgVision BV). Standardized ex vivo analyses of tumor-to-normal ratios (TNR) were performed to define the optimal tracer dose using a BlackBox imaging system (SurgVision BV) for imaging fresh bread loaf slices, a NIR fluorescence flatbed scanner (Odyssey, Li-Cor) for imaging 10µm slices of formalin-fixed paraffin-embedded (FFPE) blocks, NIR Confocal Laser Endomicroscopy (CLE, Mauna Kea Technologies) and multi-diameter single fiber reflectance and single fiber fluorescence (MDSFR/SFF) spectroscopy quantification to enable correction for the influence of tissue optical properties on fluorescence in tumor and normal breast tissue.

Results

Currently, 12 subjects have been included and analyzed in four dosing groups. All tumors showed specific tracer uptake at macroscopic and microscopic level during ex vivo analyses, confirmed by histopathology. Quantification of NIR fluorescent signals showed higher TNRs by increasing doses up to 25mg. No further increase in TNR was seen in the 50mg dose group. CLE showed the feasibility of visualization of the tracer accumulation in tumor tissue compared to normal tissue at a microscopic level. MDSFR/SFF spectroscopy objectively confirmed the dose dependency up to 25mg.

Conclusion and future perspective

Intravenous administration of bevacizumab-800CW in doses up to 50mg is safe and highly tumor specific, showing a plateau of TNR at 25mg and 50mg. Further expansion of the dosing cohorts of 10mg and 25mg with additional seven patients per group will be performed to establish the optimal dose for MFGS during BCS for an upcoming phase III multicenter randomized controlled trial. By enabling MFGS during BCS the surgical treatment of primary breast cancer patients might be optimized by a reduced need for re-excision surgery and thereby reducing the risk of co-morbidity, psychological burden, poor cosmesis and healthcare costs.

Citation Format: van Dam GM, Koller M, Qiu SQ, Linssen MD, de Vries J, Jansen L, Kelder W, de Jong JS, Jorritsma-Smit A, van der Vegt B, Robinson DJ, Nagengast WB. Phase II in-human dose escalation study of the optical molecular imaging tracer bevacizumab-800cw for molecular fluorescence guided surgery in primary breast cancer patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-01-01.

Extraction of intrinsic fluorescence from single fiber fluorescence measurements on a turbid medium: experimental validation

The detailed mechanisms associated with the influence of scattering and absorption properties on the fluorescence intensity sampled by a single optical fiber have recently been elucidated based on Monte Carlo simulated data. Here we develop an experimental single fiber fluorescence (SFF) spectroscopy setup and validate the Monte Carlo data and semi-empirical model equation that describes the SFF signal as a function of scattering. We present a calibration procedure that corrects the SFF signal for all system-related, wavelength dependent transmission efficiencies to yield an absolute value of intrinsic fluorescence. The validity of the Monte Carlo data and semi-empirical model is demonstrated using a set of fluorescent phantoms with varying concentrations of Intralipid to vary the scattering properties, yielding a wide range of reduced scattering coefficients (μ's = 0-7 mm (-1)). We also introduce a small modification to the model to account for the case of μ's = 0 mm (-1) and show its relation to the experimental, simulated and theoretically calculated value of SFF intensity in the absence of scattering. Finally, we show that our method is also accurate in the presence of absorbers by performing measurements on phantoms containing red blood cells and correcting for their absorption properties.

The effect of fluence rate on the acute response of vessel diameter and red blood cell velocity during topical 5-aminolevulinic acid photodynamic therapy

BACKGROUND

In a previous study it is shown that for topically applied ALA-PDT, PpIX concentration correlates with vascular changes including vasoconstriction and/or vascular leakage of small vessels and arterioles in the mouse epidermis and dermis. In this study we report on vascular responses induced by ALA-PDT for different fluence rates, including both changes in vessel diameter and dynamics in RBC velocity in arterioles, imaged using intra-vital confocal microscopy in skinfold chambers in hairless mice. Our interest is in the dynamics of vascular changes in the early stages of illumination.

METHODS

We have determined the total PDT dose to be relatively low, 13 J cm(-2), and fluence rates of 26, 65 and 130 mW cm(-2) were investigated. Local vascular effects occurred very soon after the start of the therapeutic illumination in ALA-PDT.

RESULTS

In this study, we did not find a significant difference between fluence rates. Arterioles were particularly sensitive to vasoconstriction during low dose PDT, often resulting in complete vasoconstriction. When we observed complete vasoconstriction, this coincided with changes in RBC velocity.

CONCLUSION

Since the therapeutic effects of PDT are dependent on a fine balance between the need for oxygen during illumination and disruption of the vasculature, the results of the present study add to our understanding of acute vascular effects during ALA-PDT and aid our efforts to optimize PDT using porphyrin pre-cursors.

Topical hexylaminolevulinate and aminolevulinic acid photodynamic therapy: complete arteriole vasoconstriction occurs frequently and depends on protoporphyrin IX concentration in vessel wall

Vascular responses to photodynamic therapy (PDT) may influence the availability of oxygen during PDT and the extent of tumor destruction after PDT. However, for topical PDT vascular effects are largely unknown. Arteriole and venule diameters were measured before and after hexylaminolevulinate (HAL) and aminolevulinic acid (ALA) PDT and related to the protoporphyrin IX (PpIX) concentration in the vessel wall. A mouse skin fold chamber model and an intravital confocal microscope allowed direct imaging of the subcutaneous vessels underlying the treated area. In both HAL and ALA groups over 60% of arterioles constricted completely, while venules generally did not respond, except for two larger veins that constricted partially. Arteriole vasoconstriction strongly correlated with PpIX fluorescence intensity in the arteriole wall. Total PpIX fluorescence intensity was significantly higher for HAL than ALA for the whole area that was imaged but not for the arteriole walls. In conclusion, complete arteriole vasoconstriction occurs frequently in both HAL and ALA based topical PDT, especially when relatively high PpIX concentrations in arteriole walls are reached. Vasoconstriction will likely influence PDT effect and should be considered in studies on topical HAL and ALA-PDT. Also, our results may redefine the vasculature as a potential secondary target for topical PDT.

In vivo quantification of the scattering properties of tissue using multi-diameter single fiber reflectance spectroscopy

Multi diameter single fiber reflectance (MDSFR) spectroscopy is a non-invasive optical technique based on using multiple fibers of different diameters to determine both the reduced scattering coefficient (μs') and a parameter γ that is related to the angular distribution of scattering, where γ = (1-g2)/(1-g1) and g1 and g2 the first and second moment of the phase function, respectively. Here we present the first in vivo MDSFR measurements of μs'(λ) and γ(λ) and their wavelength dependence. MDSFR is performed on nineteen mice in four tissue types including skin, liver, normal tongue and in an orthotopic oral squamous cell carcinoma. The wavelength-dependent slope of μs'(λ) (scattering power) is significantly higher for tongue and skin than for oral cancer and liver. The reduced scattering coefficient at 800 nm of oral cancer is significantly higher than of normal tongue and liver. Gamma generally increases with increasing wavelength; for tumor it increases monotonically with wavelength, while for skin, liver and tongue γ(λ) reaches a plateau or even decreases for longer wavelengths. The mean γ(λ) in the wavelength range 400-850 nm is highest for liver (1.87 ± 0.07) and lowest for skin (1.37 ± 0.14). Gamma of tumor and normal tongue falls in between these values where tumor exhibits a higher average γ(λ) (1.72 ± 0.09) than normal tongue (1.58 ± 0.07). This study shows the potential of using light scattering spectroscopy to optically characterize tissue in vivo.

Use of a coherent fiber bundle for multi-diameter single fiber reflectance spectroscopy

Multi-diameter single fiber reflectance (MDSFR) spectroscopy enables quantitative measurement of tissue optical properties, including the reduced scattering coefficient and the phase function parameter γ. However, the accuracy and speed of the procedure are currently limited by the need for co-localized measurements using multiple fiber optic probes with different fiber diameters. This study demonstrates the use of a coherent fiber bundle acting as a single fiber with a variable diameter for the purposes of MDSFR spectroscopy. Using Intralipid optical phantoms with reduced scattering coefficients between 0.24 and 3 mm(-1), we find that the spectral reflectance and effective path lengths measured by the fiber bundle (NA = 0.40) are equivalent to those measured by single solid-core fibers (NA = 0.22) for fiber diameters between 0.4 and 1.0 mm (r ≥ 0.997). This one-to-one correlation may hold for a 0.2 mm fiber diameter as well (r = 0.816); however, the experimental system used in this study suffers from a low signal-to-noise for small dimensionless reduced scattering coefficients due to spurious back reflections within the experimental system. Based on these results, the coherent fiber bundle is suitable for use as a variable-diameter fiber in clinical MDSFR quantification of tissue optical properties.

Quantification of the reduced scattering coefficient and phase-function-dependent parameter γ of turbid media using multidiameter single fiber reflectance spectroscopy: experimental validation

Multidiameter single fiber reflectance (MDSFR) spectroscopy is a method that allows the quantification of μs' and the phase-function-dependent parameter γ of a turbid medium by utilizing multiple fibers with different diameters. We have previously introduced the theory behind MDSFR and its limitations, and here we present an experimental validation of this method based on phantoms containing a fractal distribution of polystyrene spheres both in the absence and presence of the absorber Evans Blue.

Scattering phase function spectrum makes reflectance spectrum measured from Intralipid phantoms and tissue sensitive to the device detection geometry

Reflectance spectra measured in Intralipid (IL) close to the source are sensitive to wavelength-dependent changes in reduced scattering coefficient ([Formula: see text]) and scattering phase function (PF). Experiments and simulations were performed using device designs with either single or separate optical fibers for delivery and collection of light in varying concentrations of IL. Spectral reflectance is not consistently linear with varying IL concentration, with PF-dependent effects observed for single fiber devices with diameters smaller than ten transport lengths and for separate source-detector devices that collected light at less than half of a transport length from the source. Similar effects are thought to be seen in tissue, limiting the ability to quantitatively compare spectra from different devices without compensation.

Semi-empirical model of the effect of scattering on single fiber fluorescence intensity measured on a turbid medium

Quantitative determination of fluorophore content from fluorescence measurements in turbid media, such as tissue, is complicated by the influence of scattering properties on the collected signal. This study utilizes a Monte Carlo model to characterize the relationship between the fluorescence intensity collected by a single fiber optic probe (F(SF)) and the scattering properties. Simulations investigate a wide range of biologically relevant scattering properties specified independently at excitation (λ(x)) and emission (λ(m)) wavelengths, including reduced scattering coefficients in the range μ'(s)(λ(x)) ∈ [0.1 - 8]mm(-1) and μ'(s)(λ(m)) ∈ [0.25 - 1] × μ'(s)(λ(x)). Investigated scattering phase functions (P(θ)) include both Henyey-Greenstein and Modified Henyey-Greenstein forms, and a wide range of fiber diameters (d(f) ∈ [0.2 - 1.0] mm) was simulated. A semi-empirical model is developed to estimate the collected F(SF) as the product of an effective sampling volume, and the effective excitation fluence and the effective escape probability within the effective sampling volume. The model accurately estimates F(SF) intensities (r=0.999) over the investigated range of μ'(s)(λ(x)) and μ'(s)(λ(m)), is insensitive to the form of the P(θ), and provides novel insight into a dimensionless relationship linking F(SF) measured by different d(f).

Discovery of INCB8761/PF-4136309, a Potent, Selective, and Orally Bioavailable CCR2 Antagonist

We report the discovery of a new (S)-3-aminopyrrolidine series of CCR2 antagonists. Structure-activity relationship studies on this new series led to the identification of 17 (INCB8761/PF-4136309) that exhibited potent CCR2 antagonistic activity, high selectivity, weak hERG activity, and an excellent in vitro and in vivo ADMET profile. INCB8761/PF-4136309 has entered human clinical trials.

Measurement of tissue scattering properties using multi-diameter single fiber reflectance spectroscopy: in silico sensitivity analysis

Multiple diameter single fiber reflectance (MDSFR) measurements of turbid media can be used to determine the reduced scattering coefficient (μ'(s)) and a parameter that characterizes the phase function (γ). The MDSFR method utilizes a semi-empirical model that expresses the collected single fiber reflectance intensity as a function of fiber diameter (d(fiber)), μ'(s), and γ. This study investigated the sensitivity of the MDSFR estimates of μ'(s) and γ to the choice of fiber diameters and spectral information incorporated into the fitting procedure. The fit algorithm was tested using Monte Carlo simulations of single fiber reflectance intensities that investigated biologically relevant ranges of scattering properties (μ'(s) ∈ [0.4 - 4]mm(-1)) and phase functions (γ ∈ [1.4 - 1.9]) and for multiple fiber diameters (d(fiber) ∈ [0.2 - 1.5] mm). MDSFR analysis yielded accurate estimates of μ'(s) and γ over the wide range of scattering combinations; parameter accuracy was shown to be sensitive to the range of fiber diameters included in the analysis, but not to the number of intermediate fibers. Moreover, accurate parameter estimates were obtained without a priori knowledge about the spectral shape of γ. Observations were used to develop heuristic guidelines for the design of clinically applicable MDSFR probes.

Discovery of INCB3284, a Potent, Selective, and Orally Bioavailable hCCR2 Antagonist

We report the identification of 13 (INCB3284) as a potent human CCR2 (hCCR2) antagonist. INCB3284 exhibited an IC50 of 3.7 nM in antagonism of monocyte chemoattractant protein-1 binding to hCCR2, an IC50 of 4.7 nM in antagonism of chemotaxis activity, an IC50 of 84 μM in inhibition of the hERG potassium current, a free fraction of 58% in protein binding, high selectivity over other chemokine receptors and G-protein-coupled receptors, and acceptable oral bioavailability in rodents and primates. In human clinical trials, INCB3284 exhibited a pharmacokinetic profile suitable for once-a-day dosing (T 1/2 = 15 h).

Measurement of the reduced scattering coefficient of turbid media using single fiber reflectance spectroscopy: fiber diameter and phase function dependence

This paper presents a relationship between the intensity collected by a single fiber reflectance device (R(SF)) and the fiber diameter (d(fib)) and the reduced scattering coefficient ( μs') and phase function (p(θ)) of a turbid medium. Monte Carlo simulations are used to identify and model a relationship between R(SF) and dimensionless scattering ( μs'dfib). For μs'dfib > 10 we find that R(SF) is insensitive to p(θ). A solid optical phantom is constructed with μs' ≈ 220 mm-1 and is used to convert R(SF) of any turbid medium to an absolute scale. This calibrated technique provides accurate estimates of μs' over a wide range ([0.05 - 8] mm(-1)) for a range of d(fib) ([0.2 - 1] mm).

Associations between holotranscobalamin, vitamin B12, homocysteine and depressive symptoms in community-dwelling elders

BACKGROUND

Vitamin B12 and homocysteine have been shown to be associated with depression or depressive symptoms, but the relationship has not been universal. Both vitamin B12 and homocysteine may exert an effect via vascular mechanisms; it is possible that other mechanisms apply. Holotranscobalamin is a novel, more accurate measure of tissue vitamin B12.

OBJECTIVES

To examine associations between vitamin B12, serum folate, holotranscobalamin, homocysteine and depressive symptoms in a sample of healthy elderly.

METHODS

Cross-sectional, observational community based study.

RESULTS

Lower levels of holotranscobalamin and vitamin B12 were associated with higher levels of depressive symptoms when controlled for Mini-mental state examination scores and psychosocial and cardiovascular risk factors. Homocysteine was not associated with depressive symptoms when biological and psychosocial covariates were included.

CONCLUSIONS

It is possible that low levels of vitamin B12 or holotranscobalamin are associated with depressive symptoms via mechanisms other than vascular pathology.

Ultrasound of the posterior circumflex humeral artery

Quadrilateral space syndrome (QSS) is described as compression neuropathy of the axillary neurovascular bundle in the quadrilateral space of the shoulder. This neurovascular bundle includes the posterior circumflex humeral artery (PCHA). Historically, angiography and more recently magnetic resonance angiography have been used to assess occlusion and stenosis of the PCHA in cases of suspected QSS. These traditional imaging techniques have a number of disadvantages in terms of cost, availability, invasiveness and patient comfort. We undertook to examine the ability of ultrasound to reliably visualise the PCHA. Asymptomatic adult volunteers were recruited from staff, and patients attending the radiology department who presented for pathologies unrelated to the shoulder. We used a new technique to assess blood flow in the PCHA, performing the scan from a posterolateral approach on the upper arm just above the level of the surgical neck of the humerus. This technique enabled the scan to be undertaken with the patient seated comfortably. Fifty volunteers were recruited into the study. The mean (+/-SD) age was 35 (+/-14 years). The PCHA was visualised in all patients. Our method was able to maximise Doppler sensitivity and visualisation of the artery without discomfort to the patient in less than 10 min. Ultrasound can be used to reliably visualise the PCHA. Ultrasound has potential to be used in the assessment of the PCHA in cases of QSS.

Vitamin B12 status, homocysteine and mortality amongst community-dwelling Irish elders

BACKGROUND

Vitamin B12 deficiency is associated with hyperhomocysteinaemia, which is associated with atherosclerosis and increased mortality. High levels of vitamin B12 have also been associated with increased mortality in certain patient populations.

AIMS

We examined vitamin B12 and homocysteine status and mortality rates in a population of Irish community-dwelling elders over a 3-year period.

METHODS

Prospective, community-based observational cohort study.

RESULTS

Subjects in the highest quartile of homocysteine had increased mortality rates (14.68 vs. 7.32%, relative risk 2.09). This relationship was attenuated when controlled for the presence or absence of a history of stroke or myocardial infarction. There was no relationship between vitamin B12 status and mortality during the observation period.

CONCLUSION

Vitamin B12 levels are not associated with death rates in Irish community-dwelling elders. Homocysteine levels are associated with mortality and may act via the mechanism of atherosclerotic disease.

Discovery of INCB3344, a potent, selective and orally bioavailable antagonist of human and murine CCR2

Rational design based on a pharmacophore of CCR2 antagonists reported in the literature identified lead compound 9a with potent inhibitory activity against human CCR2 (hCCR2) but moderate activity against murine CCR2 (mCCR2). Modification on 9a led to the discovery of a potent CCR2 antagonist 21 (INCB3344) with IC(50) values of 5.1 nM (hCCR2) and 9.5 nM (mCCR2) in binding antagonism and 3.8 nM (hCCR2) and 7.8 nM (mCCR2) in antagonism of chemotaxis activity. INCB3344 exhibited >100-fold selectivity over other homologous chemokine receptors, a free fraction of 24% in human serum and 15% in mouse serum, and an oral bioavailability of 47% in mice, suitable as a tool compound for target validation in rodent models.

Monte Carlo analysis of single fiber reflectance spectroscopy: photon path length and sampling depth

Single fiber reflectance spectroscopy is a method to noninvasively quantitate tissue absorption and scattering properties. This study utilizes a Monte Carlo (MC) model to investigate the effect that optical properties have on the propagation of photons that are collected during the single fiber reflectance measurement. MC model estimates of the single fiber photon path length (L(SF)) show excellent agreement with experimental measurements and predictions of a mathematical model over a wide range of optical properties and fiber diameters. Simulation results show that L(SF) is unaffected by changes in anisotropy (g epsilon [0.8, 0.9, 0.95]), but is sensitive to changes in phase function (Henyey-Greenstein versus modified Henyey-Greenstein). A 20% decrease in L(SF) was observed for the modified Henyey-Greenstein compared with the Henyey-Greenstein phase function; an effect that is independent of optical properties and fiber diameter and is approximated with a simple linear offset. The MC model also returns depth-resolved absorption profiles that are used to estimate the mean sampling depth (Z(SF)) of the single fiber reflectance measurement. Simulated data are used to define a novel mathematical expression for Z(SF) that is expressed in terms of optical properties, fiber diameter and L(SF). The model of sampling depth indicates that the single fiber reflectance measurement is dominated by shallow scattering events, even for large fibers; a result that suggests that the utility of single fiber reflectance measurements of tissue in vivo will be in the quantification of the optical properties of superficial tissues.

Optimizing ALA-PDT in the management of non-melanoma skin cancer by fractionated illumination

The aim of this review was to describe briefly the mechanism and history of photodynamic therapy (PDT). The achieved preclinical and clinical results in Rotterdam are discussed in the light of a search to optimize aminolevulinic acid-photodynamic therapy (ALA-PDT). As the incidence of skin cancer is rising, an optimized treatment in non-melanoma skin cancer is needed.

A review of photodynamic therapy in cutaneous leishmaniasis

We present a review of six clinical studies investigating the use of photodynamic therapy (PDT) using porphyrin precursors for the treatment of Old World cutaneous leishmaniasis (CL). Thirty-nine patients with a total of 77 lesions received PDT using a range of treatment schedules following topical application of aminolevulinic acid (ALA) or methyl-aminolevulinate (MAL). The tissue response to PDT is accompanied by a mild burning sensation, erythema and reversible hypo- and hyperpigmentation. Few mechanistic studies have addressed the principles underlying the use of PDT for CL. All six reviewed papers suggest that PDT with porphyrin precursors is relatively effective in treating CL. Data are still limited, and PDT cannot at this point be recommended in routine clinical practice. The mechanism of action of this promising therapeutic modality needs to investigated further and additional controlled trials need to be performed.

Performance of a dedicated light delivery and dosimetry device for photodynamic therapy of nasopharyngeal carcinoma: phantom and volunteer experiments

The objective of this study was to develop a light delivery and measurement device for photodynamic therapy (PDT) in the nasopharyngeal cavity, which achieves a homogeneous and reproducible fluence rate distribution to a target area and provides proper shielding of predefined risk areas.

MATERIALS AND METHODS

A flexible silicone applicator was developed, incorporating light delivery and dosimetry fibers. The applicator can be inserted through the mouth and fixed in the nasopharyngeal cavity. Tissue optical phantoms were prepared on the basis of optical properties measured in vivo using diffuse reflectance spectroscopy (DRS). The fluence rate over the length of the applicator surface was measured in air, in tissue optical phantoms and in five healthy volunteers.

RESULTS

The fluence rate distribution over the applicator surface in air and tissue optical phantom was found to be more homogeneous (SD/mean 3.8% and 18.3%, respectively) than the fluence rate distribution in five volunteers (SD/mean ranging from 19% up to 52%). The maximum observed fluence rate build-up in the nasopharynx varied between subjects and ranged from a factor of 4.1-6.9. Shielding of the risk area such as the soft palate and tongue was effective.

CONCLUSIONS

In air and in tissue optical phantoms the fluence rate distribution of the device was highly homogeneous. The observed inter-subject and intra-subject variations in fluence rate in healthy volunteers originated from differences in optical properties and nasopharyngeal geometry. Light delivery based on a single tissue surface measurement will not be adequate. In situ dosimetric measurements are required to determine the light fluence delivered to a geometrically complex site such as the nasopharynx. These observations should be taken in consideration when developing light applicators for PDT of the nasopharynx and other non-uniform surfaces.

Fractionated illumination after topical application of 5-aminolevulinic acid on normal skin of hairless mice: The influence of the dark interval

We have previously shown that light fractionation during topical aminolevulinic acid based photodynamic therapy (ALA-PDT) with a dark interval of 2h leads to a significant increase in efficacy in both pre-clinical and clinical PDT. However this fractionated illumination scheme required an extended overall treatment time. Therefore we investigated the relationship between the dark interval and PDT response with the aim of reducing the overall treatment time without reducing the efficacy. Five groups of mice were treated with ALA-PDT using a single light fraction or the two-fold illumination scheme with a dark interval of 30 min, 1, 1.5 and 2h. Protoporphyrin IX fluorescence kinetics were monitored during illumination. Visual skin response was monitored in the first seven days after PDT and assessed as PDT response. The PDT response decreases with decreasing length of the dark interval. Only the dark interval of 2h showed significantly more damage compared to all the other dark intervals investigated (P<0.05 compared to 1.5h and P<0.01 compared to 1h, 30 min and a single illumination). No relationship could be shown between the utilized PpIX fluorescence during the two-fold illumination and the PDT response. The rate of photobleaching was comparable for the first and the second light fraction and not dependent of the length of dark interval used. We conclude that in the skin of the hairless mouse the dark interval cannot be reduced below 2h without a significant reduction in PDT efficacy.

Laser speckle imaging of dynamic changes in flow during photodynamic therapy

We present a study investigating the use of laser speckle imaging (LSI) for monitoring blood flow during photodynamic therapy (PDT) utilizing the therapeutic illumination radiation. The coherent nature of a laser source, often used in PDT, offers the possibility of obtaining information on the blood flow without interrupting treatment. We have found that in the rat skin-fold observation chamber, it is possible to monitor the vasculature response to PDT in individual arteries, veins and in tumour microvasculature with significantly higher spatial and temporal resolution than current methods. This illustrates the potential for LSI for monitoring PDT, in particular for vascular-localizing photosensitizers, where current non-invasive methods are difficult because of high absorption due to blood and the specific localization of photosensitizer within the vasculature. However, critical problems need to be further investigated and solved, like the influence of tissue sampling volume, changing of optical properties and movement artefacts from other vessels on the LSI signal. Until then, the real potential of LSI for monitoring blood flow remains of limited value.

In vivo fluence rate measurements during Foscan-mediated photodynamic therapy of persistent and recurrent nasopharyngeal carcinomas using a dedicated light applicator

The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy-induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan absorption.

Monitoring PDT by means of superficial reflectance spectroscopy

Monitoring of relevant parameters during photodynamic therapy (PDT) and correlating these with treatment response is necessary to guarantee optimal and reproducible treatment outcome. In this paper we study the correlation between changes in the local tissue optical properties (absorption and scattering coefficients) during ALA-PDT and changes in PpIX fluorescence. The optical properties are measured extremely superficially by employing a single fiber for the delivery and collection of white light to and from the tissue. The measured reflectance spectrum is modeled in terms of four relevant parameters: blood saturation, relative blood volume fraction, scattering intensity and wavelength dependence of the scattering. All these parameters, except the relative blood volume fraction, are shown to correlate with the rate of photobleaching of PpIX, which in turn has previously been shown to correlate with the response of tissues to PDT. These results yield valuable insight in the behavior of these parameters during PDT and their suitability to predict PDT-response for other photosensitizers for which monitoring through photobleaching is not possible.

Begomoviruses from mungbeans in Pakistan: epitope profiles, DNA A sequences and phylogenetic relationships

Monoclonal antibodies raised against particles of African Cassava mosaic virus, Indian Cassava mosaic virus or Okra leaf curl virus were used to test samples collected in Pakistan from begomovirus-infected plants. Epitope profiles obtained from cucurbits resembled those previously reported for Pakistani begomoviruses. In contrast, epitope profiles obtained from legumes showed little diversity and were quite distinct from these. DNA with nucleotide sequences typical of begomovirus DNA A components was amplified from selected mungbean samples. Comparisons of the sequences of the amplified DNA with other begomovirus DNA A sequences and phylogenetic analysis revealed that the Pakistani mungbean viruses were isolates of the species Mungbean yellow mosaic India virus, which together with Mungbean yellow mosaic virus represents a distinct lineage of Old World begomoviruses.

Monitoring in situ dosimetry and protoporphyrin IX fluorescence photobleaching in the normal rat esophagus during 5-aminolevulinic acid photodynamic therapy

Experimental therapies for Barrett's esophagus, such as 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT), aim to ablate the premalignant Barrett's epithelium. However, the reproducibility of the effects should be improved to optimize treatment. Accurate irradiation with light of a proper wavelength (633 nm), fluence and fluence rate has shown to be critical for successful ALA-PDT. Here, we have used in situ light dosimetry to adjust the fluence rate measured within the esophagus for individual animals and monitored protoporphyrin IX (PpIX) fluorescence photobleaching simultaneously. Rats were administered 200 mg kg-1 ALA (n = 14) or served as control (n = 7). Animals were irradiated with an in situ measured fluence rate of 75 mW cm-2 and a fluence of 54 J cm-2. However, this more accurate method of light dosimetry did not decrease the variation in tissue response. Large differences were also observed in the dynamics of PpIX fluorescence photobleaching in animals that received the same measured illumination parameters. We found that higher PpIX fluorescence photobleaching rates corresponded with more epithelial damage, whereas lower rates corresponded with no response. A two-phased decay in PpIX fluorescence could be identified in the response group, with a rapid initial phase followed by a slower rate of photobleaching. Non-responders did not show the rapid initial decay and had a significantly lower rate of photobleaching during the second phase of the decay (P = 0.012).

Monitoring In Situ Dosimetry and Protoporphyrin IX Fluorescence Photobleaching in the Normal Rat Esophagus During 5-Aminolevulinic Acid Photodynamic Therapy¶

Experimental therapies for Barrett's esophagus, such as 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT), aim to ablate the premalignant Barrett's epithelium. However, the reproducibility of the effects should be improved to optimize treatment. Accurate irradiation with light of a proper wavelength (633 nm), fluence and fluence rate has shown to be critical for successful ALA-PDT. Here, we have used in situ light dosimetry to adjust the fluence rate measured within the esophagus for individual animals and monitored protoporphyrin IX (PpIX) fluorescence photobleaching simultaneously. Rats were administered 200 mg kg-1 ALA (n = 14) or served as control (n = 7). Animals were irradiated with an in situ measured fluence rate of 75 mW cm-2 and a fluence of 54 J cm-2. However, this more accurate method of light dosimetry did not decrease the variation in tissue response. Large differences were also observed in the dynamics of PpIX fluorescence photobleaching in animals that received the same measured illumination parameters. We found that higher PpIX fluorescence photobleaching rates corresponded with more epithelial damage, whereas lower rates corresponded with no response. A two-phased decay in PpIX fluorescence could be identified in the response group, with a rapid initial phase followed by a slower rate of photobleaching. Non-responders did not show the rapid initial decay and had a significantly lower rate of photobleaching during the second phase of the decay (P = 0.012).

Umbravirus-encoded proteins both stabilize heterologous viral RNA and mediate its systemic movement in some plant species

The proteins encoded by open reading frame 3 (ORF3) of the umbraviruses pea enation mosaic virus-2 and tobacco mottle virus, like that of groundnut rosette virus, mediated the movement of viral RNA through the phloem of infected Nicotiana benthamiana or N. clevelandii plants when they were expressed from chimeric tobacco mosaic virus in place of the coat protein. However, these chimeras did not move systemically in N. tabacum. In lysates of N. benthamiana or N. tabacum protoplasts, the chimeric RNAs were more stable than was RNA of tobacco mosaic virus lacking the coat protein gene. The chimeric viruses also protected the latter in trans, suggesting that the ORF3 proteins can increase the stability of heterologous viral RNA. Umbraviral ORF3 proteins contain a conserved arginine-rich domain, and the possible roles of this motif in the functions of the proteins are discussed.

In vivo pharmacokinetics of protoporphyrin IX accumulation following intracutaneous injection of 5-aminolevulinic acid

Photodynamic therapy with 5-aminolevulinic acid (ALA) derived protoporphyrin IX (PpIX) as photosensitizer is a promising treatment for basal cell carcinomas. Until now ALA has been administered topically as an oil-in-water cream in most investigations. The disadvantage of this administration route is insufficiënt penetration in deeper, nodular tumours. Therefore we investigated intracutaneous injection of ALA as an alternative administration route. ALA was administered in 6-fold in the normal skin of three 6-week-old female Dutch pigs by intracutaneous injection of an aqueous solution of ALA (pH 5.0) in volumes of 0.1-0.5 ml and concentrations of 0.5-2% and by topical administration of a 20% ALA cream. During 8 h fluorescence of ALA derived PpIX was measured under 405 nm excitation. For the injection the measured fluorescence was shown to be dose dependent. All injected doses of 3 mg ALA or more lead to a faster initial increase rate of PpIX synthesis and significantly greater fluorescence than that measured after topical administration of ALA. Irradiation (60 Jcm(-2) for 10 min) of the spots was performed at 3.5 h after ALA administration. After 48 and 96 h visual damage scores were evaluated and biopsies were taken for histopathological examination. After injection of 2 mg ALA or more the PDT damage after illumination was shown to be significantly greater than after topical application of 20% ALA. An injected dose of 10 mg ALA (0.5 ml of a 2% solution) resulted in significantly more tissue damage after illumination than all other injected doses.

Modeling platinum group metal complexes in aqueous solution

We construct force fields suited for the study of three platinum group metals (PGM) as chloranions in aqueous solution from quantum chemical computations and report experimental data. Density functional theory (DFT) using the local density approximation (LDA), as well as extended basis sets that incorporate relativistic corrections for the transition metal atoms, has been used to obtain equilibrium geometries, harmonic vibrational frequencies, and atomic charges for the complexes. We found that DFT calculations of [PtCl(6)](2-).3H(2)O, [PdCl(4)](2-).2H(2)O, and [RhCl(6)](3-).3H(2)O water clusters compared well with molecular mechanics (MM) calculations using the specific force field developed here. The force field performed equally well in condensed phase simulations. A 500 ps molecular dynamics (MD) simulation of [PtCl(6)](2-) in water was used to study the structure of the solvation shell around the anion. The resulting data were compared to an experimental radial distribution function derived from X-ray diffraction experiments. We found the calculated pair correlation functions (PCF) for hexachloroplatinate to be in good agreement with experiment and were able to use the simulation results to identify and resolve two water-anion peaks in the experimental spectrum.

Topical 5-aminolevulinic acid-photodynamic therapy of hairless mouse skin using two-fold illumination schemes: PpIX fluorescence kinetics, photobleaching and biological effect

Light fractionation with dark periods of the order of hours has been shown to considerably increase the efficacy of 5-aminolevulinic acid-photodynamic therapy (ALA-PDT). Recent investigations have suggested that this increase may be due to the resynthesis of protoporphyrin IX (PpIX) during the dark period following the first illumination that is then utilized in the second light fraction. We have investigated the kinetics of PpIX fluorescence and PDT-induced damage during PDT in the normal skin of the SKH1 HR hairless mouse. A single illumination (514 nm), with light fluences of 5, 10 and 50 J cm-2 was performed 4 h after the application of 20% ALA, to determine the effect of PDT on the synthesis of PpIX. Results show that the kinetics of PpIX fluorescence after illumination are dependent on the fluence delivered; the resynthesis of PpIX is progressively inhibited following fluences above 10 J cm-2. In order to determine the influence of the PpIX fluorescence intensity at the time of the second illumination on the visual skin damage, 5 + 95 and 50 + 50 J cm-2 (when significantly less PpIX fluorescence is present before the second illumination), were delivered with a dark interval of 2 h between light fractions. Each scheme was compared to illumination with 100 J cm-2 in a single fraction delivered 4 or 6 h after the application of ALA. As we have shown previously greater skin damage results when an equal light fluence is delivered in two fractions. However, significantly more damage results when 5 J cm-2 is delivered in the first light fraction. Also, delivering 5 J cm-2 at 5 mW cm-2 + 95 J cm-2 at 50 mW cm-2 results in a reduction in visual skin damage from that obtained with 5 + 95 J cm-2 at 50 mW cm-2. A similar reduction in damage is observed if 5 + 45 J cm-2 are delivered at 50 mW cm-2. PpIX photoproducts are formed during illumination and subsequently photobleached. PpIX photoproducts do not dissipate in the 2 h dark interval between illuminations.

Multiple infection, recombination and genome relationships among begomovirus isolates found in cotton and other plants in Pakistan

Begomoviruses occur in many plant species in Pakistan and are associated with an epidemic of cotton leaf curl disease that has developed since 1985. PCR analysis with primer pairs specific for each of four already sequenced types of DNA-A of cotton leaf curl virus (CLCuV-PK types a, 26, 72b and 804a), or for okra yellow vein mosaic virus (OYVMV), indicated that many individual naturally infected plants of cotton and other malvaceous species contained two or three begomovirus sequences. Similarly, sequence differences among overlapping fragments of begomovirus DNA-A, amplified from individual naturally infected plants, indicated much multiple infection in malvaceous and non-malvaceous species. Some cotton plants contained DNA-A sequences typical of begomoviruses from non-malvaceous species, and some non-malvaceous plants contained sequences typical of CLCuV-PK. Some DNA-A sequences were chimaeric; they each included elements typical of different types of CLCuV-PK, or of different malvaceous and/or non-malvaceous begomoviruses. Often an apparent recombination site occurred at the origin of replication. No complete CLCuV-PK DNA-A sequence was found in malvaceous or non-malvaceous species collected in Pakistan outside the area of the cotton leaf curl epidemic but chimaeric sequences, including a part that was typical of CLCuV-PK DNA-A, did occur there. We suggest that recombination among such pre-existing sequences was crucial for the emergence of CLCuV-PK. Recombination, following multiple infection, could also explain the network of relationships among many of the begomoviruses found in the Indian subcontinent, and their evolutionary divergence, as a group, from begomoviruses causing similar diseases in other geographical regions.

Infective endocarditis in intravenous drug users: does HIV status alter the presenting temperature and white blood cell count?

The intent of this study was to determine if HIV seropositivity alters the maximum temperature (T(max)) and WBC count of febrile intravenous (i.v.) drug users with infective endocarditis (IE). A review of 497 charts of patients with endocarditis provided 228 eligible patient visits (46%), with 158 cases (69.3%) of IE among 126 patients (74 HIV+ and 52 HIV-). Mean T(max) for all patients with IE was 39.1 degrees C (102.4 degrees F). Mean T(max) was similar between the HIV+ (39.1 degrees C, 102.4 degrees F) and HIV- (39.2 degrees C, 102.5 degrees F) groups. There were no differences in mean T(max) among HIV+ patients with CD4 counts > 200 (39.0 degrees C, 102.3 degrees F), those with CD4 < or =200 (39.2 degrees C, 102.5 degrees F), and the HIV- group (39.2 degrees C, 102.5 degrees F). Nearly 8% of i.v. drug users with confirmed IE presented to the ED with a T(max) below 37.8 degrees C (100.0 degrees F). Mean WBC count was significantly lower in HIV+ (11.1 k/mm(3)) than in HIV- patients (15.4 k/mm(3)) and significantly lower in the group with CD4 < or =200 (8.0 k/mm(3)) than in the HIV- group. In conclusion, HIV infection was not associated with lower T(max), but it was associated with decreased WBC count in the general HIV+ group and in the group with CD4 < or =200.

A new system for sternal intraosseous infusion in adults

BACKGROUND

Intraosseous (IO) infusion provides an alternative route for the administration of fluids and medications when difficulty with peripheral or central lines is encountered during resuscitation of critically ill and injured patients.

OBJECTIVE

To report the first 50 uses of a new system for emergency IO infusion into the sternum in adults, the Pyng F.A.S.T.1 IO infusion system.

METHODS

Six emergency departments and five prehospital emergency medical services (EMS) sites in Canada and the United States provided clinical and/or research data on their use of the IO system in a pilot study of success rates, insertion times, and complications. Indications for use included adult patient, urgent need for fluids or medications, and unacceptable delay or inability to achieve standard vascular access. A basic data set was standardized for all sites, and some sites collected additional data.

RESULTS

The overall success rate for achieving vascular access with the system was 84%. Success rates were 74% for first-time users, and 95% for experienced users. Failure to achieve vascular access occurred most frequently in patients (5 of 9) described subjectively by the user as "very obese," in whom there was a thick layer of tissue overlying the sternum. Mean time to achieve vascular access was 77 seconds. Flow rates of up to 80 mL/min were reported for gravity drip, and more than 150 mL/min by syringe bolus. Pressure cuffs were also used successfully, although fluid rate was controlled by clamping the line. Further research on flow rates is needed. No complications or complaints were reported at two-month follow-up.

CONCLUSION

These early data indicate that sternal IO infusion using the new F.A.S.T.1 IO system may provide rapid, safe vascular access and may be a useful technique for reducing unacceptable delays in the provision of emergency treatment.

Improved response of plaque psoriasis after multiple treatments with topical 5-aminolaevulinic acid photodynamic therapy

We investigated the clinical response of 10 patients with plaque psoriasis to multiple treatments with photodynamic therapy, using topical application of 5-aminolaevulinic acid followed by exposure to broad-band visible radiation. Treatment was performed up to 3 times per week, with a maximum of 12 treatments, using a light dose of 8 Jcm(-2) delivered at a dose-rate of 15 mW cm(-2). Eight patients showed a clinical response. Out of 19 treated sites, 4 cleared, 10 responded but did not clear and 5 showed no improvement. Of the 4 sites that cleared only 1 did so fully, after 7 treatments, 45 days after the start of therapy. Of the 10 sites that responded partially, the greatest reduction in scale, erythema and induration index occurred after a minimum of 3 and a maximum of 8 treatments. The intensity of 5-aminolaevulinic acid-induced protoporphyrin IX fluorescence, recorded prior to the first treatment, varied between sites on the same patient as well as between patients. There was also a variation in fluorescence intensity recorded from the same site immediately prior to subsequent treatments, although the pretreatment levels generally decreased as the study progressed and then increased as psoriasis relapsed. Biopsies confirmed that fluorescence was localized throughout the epidermis and stratum corneum, but the level was not consistent between sections taken within the same biopsy. We also observed fluorescence at sites distant from the ones that received 5-aminolaevulinic acid, which was not present prior to the start of the treatment programme, but found no evidence of elevated levels of plasma porphyrins. The level of discomfort associated with this therapy increased with increasing values of the calculated photodynamic dose, defined as the product of the initial photosensitizer concentration and the percentage reduction in fluorescence following irradiation. Therefore, although clinical efficacy improved with multiple treatments, unpredictable response and patient discomfort make ALA-PDT unsuitable for the treatment of psoriasis.

Spatiotemporal separation of groundnut rosette disease agents

ABSTRACT Analysis by triple-antibody sandwich enzyme-linked immunosorbent assay of groundnut samples from fields in two seasons from different regions of Malawi showed the absence of groundnut rosette assistor virus (GRAV) from some plants showing groundnut rosette disease symptoms and the presence of GRAV in some symptomless plants. Viruliferous Aphis craccivora collected from fields transmitted either GRAV alone, groundnut rosette virus (GRV) with its satellite RNA (sat RNA), or all three agents together, in different proportions. More plants became infected with all three agents when increasing numbers of potentially viruliferous aphids were used per plant, suggesting a dosage response. Electrical pentration graph studies of aphid stylet activities indicated successful transmission of GRV and its sat RNA during both the "stylet pathway phase" and salivation into sieve elements, whereas GRAV was transmitted only during the latter phase. Aphids transmitted all three agents together only during the salivation phase. Reverse-transcriptase polymerase chain reaction testing of viruliferous aphids and of inoculated plants revealed no correlation between the presence of all three agents in prospective aphid vectors and their simultaneous transmission to groundnut plants. These results show that separation of the groundnut rosette disease agents occurs over time and space.

Erythroplasia of Queyrat treated by topical aminolaevulinic acid photodynamic therapy

Erythroplasia of Queyrat (EQ) is an intraepithelial carcinoma in situ affecting the mucosal surfaces of the penis, with a significant risk of invasion and metastasis. Treatment is often difficult and is associated with significant recurrence rates. Topical 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) combines a photosensitizer precursor and visible light to produce a photodynamic effect. It has been used successfully to treat benign, premalignant and malignant skin diseases. We present four patients with EQ who have been treated by topical ALA PDT. Of two patients with limited disease one has achieved a long-term complete response (36 months) and the other developed a recurrence at 18 months after a complete response. Two further patients with more extensive disease achieved a significant improvement, allowing easier treatment by laser vaporization. Although topical ALA PDT offers the advantages of tumour specificity, preservation of function and a good cosmetic result, more extensive EQ appears less responsive to this new therapeutic modality using current treatment parameters.

A plant virus-encoded protein facilitates long-distance movement of heterologous viral RNA

Transport of plant viruses from cell to cell typically involves one or more viral proteins that supply specific cell-to-cell movement functions. Long-distance transport of viruses through the vascular system is a less well understood process with requirements different from those of cell-to-cell movement. Usually viral coat protein (CP) is required for long-distance movement, but groundnut rosette umbravirus (GRV) does not code for a CP. However, this virus moves efficiently from cell to cell and long distance. We demonstrate here that the protein encoded by ORF3 of GRV can functionally replace the CP of tobacco mosaic virus (TMV) for long-distance movement. In spite of low levels of virus RNA accumulation in infected cells, chimeric TMV with a replacement of the CP gene by GRV ORF3 was able to move rapidly through the phloem. Moreover, this chimeric virus complemented long-distance movement of another CP-deficient TMV derivative expressing the gene encoding the green fluorescent protein. Thus, the GRV ORF3-encoded protein represents a class of trans-acting long-distance movement factors that can facilitate trafficking of an unrelated viral RNA.

Improvement of systemic 5-aminolevulinic acid-based photodynamic therapy in vivo using light fractionation with a 75-minute interval

We have studied different single and fractionated illumination schemes after systemic administration of 5-aminolevulinic acid (ALA) to Improve the response of nodular tumors to ALA-mediated photodynamic therapy. Tumors transplanted on the thigh of female WAG/Rij rats were transdermally illuminated with red light (633 nm) after systemic ALA administration (200 mg/kg). The effectiveness of each treatment scheme was determined from the tumor volume doubling time. A single illumination (100 J/cm2 at 100 mW/cm2, 2.5 h after ALA administration) yielded a doubling time of 6.6+/-1.2 days. This was significantly different from the untreated control (doubling time, 1.7+/-0.1 days). The only treatment scheme that yielded a significant improvement compared to all other schemes studied was illumination at both 1 and 2.5 h after ALA administration (both 100 J/cm2 at 100 mW/cm2) and resulted in a tumor volume doubling time of 18.9+/-2.9 days. A possible mechanism to explain this phenomenon is that the protoporphyrin IX formed after administration of ALA is photodegraded by the first illumination. In the 75-min interval, new porphyrin is formed enhancing the effect of the second illumination.

Satellite RNA is essential for encapsidation of groundnut rosette umbravirus RNA by groundnut rosette assistor luteovirus coat protein

Groundnut rosette disease is caused by a complex of agents comprising groundnut rosette umbravirus (GRV), GRV satellite RNA (sat-RNA)groundnut rosette assistor luteovirus (GRAV). Both GRAV and GRV sat-RNA are needed for GRV to be aphid transmissible. To understand the role of GRAVGRV sat-RNA in the aphid transmission of GRV, encapsidation of GRV genomicsatellite RNAs has been studied using transgenic Nicotiana benthamiana plants expressing GRAV coat protein (CP). GRAV CP expressed from a transgene was shown to package GRV genomicsatellite RNAs efficiently, giving a high yield of transcapsidated virus particles. GRV sat-RNA was absolutely essential for this process. GRV genomic RNA was not encapsidated by GRAV CP in the absence of the sat-RNA. Using different mutants of GRV sat-RNA, it was found that some property of full-length satellite RNA molecules, such as size or specific conformation rather than potential open reading frames, was required for the production of virus particles. A correlation between the ability of sat-RNA to stimulate encapsidation of GRV RNA by GRAV CPits capacity to promote aphid transmission of GRV was observed.