Generation of precision preclinical cancer models using regulated in vivo base editing

Although single-nucleotide variants (SNVs) make up the majority of cancer-associated genetic changes and have been comprehensively catalogued, little is known about their impact on tumor initiation and progression. To enable the functional interrogation of cancer-associated SNVs, we developed a mouse system for temporal and regulatable in vivo base editing. The inducible base editing (iBE) mouse carries a single expression-optimized cytosine base editor transgene under the control of a tetracycline response element and enables robust, doxycycline-dependent expression across a broad range of tissues in vivo. Combined with plasmid-based or synthetic guide RNAs, iBE drives efficient engineering of individual or multiple SNVs in intestinal, lung and pancreatic organoids. Temporal regulation of base editor activity allows controlled sequential genome editing ex vivo and in vivo, and delivery of sgRNAs directly to target tissues facilitates generation of in situ preclinical cancer models.

When less is more: does more Na+-cations mean more adsorption sites for toluene in faujasites?

The unique properties of zeolites make them an interesting material to be used in separation processes. The possibility of tailoring some of their characteristics, like the Si/Al ratio, allows optimizing their synthesis for a given task. Concerning the adsorption of toluene by faujasites an understanding of the effect of cations is necessary to foster the elaboration of new materials, which can capture molecules with a high degree of selectivity and sensitivity. Undoubtedly, this knowledge is relevant for a wide range of applications going from the elaboration of technologies for improving the air-quality to diagnostic procedures to prevent health risks. The studies reported here using Grand Canonical Monte Carlo simulations elucidate the role of Na-cations in the adsorption of toluene by faujasites with different Si/Al ratios. They detail how the location of the cations inhibits or enhances the adsorption. The cations located at site II are shown to be those enhancing the adsorption of toluene on faujasites. Interestingly, the cations located at site III generate a hindrance at high loading. This becomes an impediment for the organization of toluene molecules inside faujasites.

Hypofractionated postoperative stereotactic radiotherapy for large resected brain metastases

PURPOSE

The aim of the present retrospective study was to report outcomes after hypofractionated stereotactic radiotherapy (HSRT) for resected brain metastases (BM).

PATIENTS AND METHODS

We reviewed results of patients with resected BM treated with postoperative HSRT (3×7.7Gy to the prescription isodose 70%) between May 2013 and June 2020. Local control (LC), distant brain control (DBC), overall survival (OS), leptomeningeal disease relapse (LMDR), and radiation necrosis (RN) occurrence were reported.

RESULTS

Twenty-two patients with 23 brain cavities were included. Karnofsky Performance status (KPS) was≥70 in 77.3%. Median preoperative diameter was 37mm [21.0-75.0] and median planning target volume (PTV) was 23 cm³ [9.9-61.6]. Median time from surgery to SRT was 69 days [7-101] and 48% of patients had a local relapse on pre-SRT imaging. Median follow-up was 17.5 months [1.6-95.9]. One and two-year LC rates were 60.9 and 52.2% respectively. One and 2-year DBC rates were 45.5 and 40.9%. Median OS was 16.5 months. Four patients (18.2%) presented LMDR during follow-up. RN occurred in 6 patients (27.2%). Three factors were associated with OS: ECOG-PS (P=0.009), KPS (P=0.04), and cystic metastasis before surgery (P=0.037). Several factors were related to RN occurrence: PTV diameter and volume, Normal brain V21, V21 and V24 isodoses volumes.

CONCLUSION

HSRT is the most widely used scheme for larger brain cavities after surgery. The optimal dose and scheme remain to be defined as well as the optimal delay between postoperative SRT and surgery. Dose escalation may be necessary, especially in case of subtotal resection.

Base editing sensor libraries for high-throughput engineering and functional analysis of cancer-associated single nucleotide variants

Base editing can be applied to characterize single nucleotide variants of unknown function, yet defining effective combinations of single guide RNAs (sgRNAs) and base editors remains challenging. Here, we describe modular base-editing-activity 'sensors' that link sgRNAs and cognate target sites in cis and use them to systematically measure the editing efficiency and precision of thousands of sgRNAs paired with functionally distinct base editors. By quantifying sensor editing across >200,000 editor-sgRNA combinations, we provide a comprehensive resource of sgRNAs for introducing and interrogating cancer-associated single nucleotide variants in multiple model systems. We demonstrate that sensor-validated tools streamline production of in vivo cancer models and that integrating sensor modules in pooled sgRNA libraries can aid interpretation of high-throughput base editing screens. Using this approach, we identify several previously uncharacterized mutant TP53 alleles as drivers of cancer cell proliferation and in vivo tumor development. We anticipate that the framework described here will facilitate the functional interrogation of cancer variants in cell and animal models.

P1475Impact of automatic screening and parasternal rights positions in the eligibility of patients with hypertrophic cardiomyopathy for subcutaneous automatic cardioverter defibrillator implant

Background

A high percentage of failures in the detection of QRS and T wave in patients (pts) with hypertrophic cardiomyopathy (HCM) have been reported. This finding would prevent them from being eligible for an implantable subcutaneous automatic defibrillator (S-ICD). However, recently 2 changes in the detection have been proposed, automatic screening and the use of right parasternal position of the lead. 

The aim of our work was to study if the elegibility proportion of patients  was increased with both 2 advacements.

Methods

We included 31 patients (18 male)with a diagnosis of HCM and at least 1 risk factor for sudden death, in follow-up at the outdoor clinic of of 2 cardiology centers. We performed elegibility screening test in supine position and standing using both the automatic screening (AS) obtained by Boston Scientific Zoom Latitude programmer) and the manual (MS), to simulate the detection of the 3 vectors utilized in S-ICD detection. And both screens were registered with the surface electrodes in parasternal left and right position. A pte was considered eligible if at least one vector was correct in supine position and in standing position, well in parasternal left or right position.

Results

Using MS with left parasternal position, 22 patients (71%) were eligible.  Adding the right parasternal lead, the eligibility increased by 10%,  reaching 81%. In addition, in automatic screening, eligibility in right shifts (81%) it is 7% more than in the left and, with the addition of the rights to the left, the eligibility reaches up to 84%. Figure shows the three-lead ECG factors influencing screening pass vs failure.

Conclusion

AS, right parasternal lead position and the combination of right and left parasternal lead position, increase the eligibility of sICD candidates with HCM.

Abstract Figure. ECG factors influencing screening pass

Thermal effects during adsorption of n-butane on a silicalite-1 membrane: A non-equilibrium molecular dynamics study

Non-equilibrium molecular dynamic (NEMD) simulations have been used to study the kinetics of adsorption of n-butane molecules in a silicalite membrane. We have chosen this simple well-known process to demonstrate that the process is characterized by two stages, both non-isothermal. In the first stage the large chemical driving force leads to a rapid uptake of n-butane in all the membrane and a simultaneous increase in the membrane temperature, explained by the large enthalpy of adsorption, DeltaH=-61.6kJ/mol butane. A diffusion coefficient for transport across the external surface layer is calculated from the relaxation time; a value of 3.4x10(-9)m(2)/s is found. During the adsorption, a significant thermal driving force develops across the external surface of the membrane, which leads to an energy flux out of the membrane during the second stage. In this stage a thermal conductivity of 3.4x10(-4)W/Km is calculated from the corresponding relaxation time for the surface, confirming that the thermal conduction is the rate-limiting step. The aim of this paper is to demonstrate that a thermal driving force must be taken into account in addition to a chemical driving force in the description of transport in nano-porous materials.

Transfer coefficients for evaporation of a system with a Lennard-Jones long-range spline potential

Surface transfer coefficients are determined by nonequilibrium molecular dynamics simulations for a Lennard-Jones fluid with a long-range spline potential. In earlier work [A. Røsjorde, J. Colloid Interface Sci. 240, 355 (2001); J. Xu, ibid. 299, 452 (2006)], using a short-range Lennard-Jones spline potential, it was found that the resistivity coefficients to heat and mass transfer agreed rather well with the values predicted by kinetic theory. For the long-range Lennard-Jones spline potential considered in this paper we find significant discrepancies from the values predicted by kinetic theory. In particular the coupling coefficient, and as a consequence the heat of transfer on the vapor side of the surface are much larger. Thermodynamic data for the liquid-vapor equilibrium confirmed the law of corresponding states for the surface, when it is described as an autonomous system. The importance of these findings for modelling phase transitions is discussed.

Interface Film Resistivities for Heat and Mass TransfersIntegral Relations Verified by Non-equilibrium Molecular Dynamics

Integral relations that predict interface film transfer coefficients for evaporation and condensation have recently been derived. According to these relations, all coefficients can be calculated for one-component systems, using the thermal resistivity and the enthalpy profile through the interface. The integral relations were tested in this work using nonequilibrium molecular dynamics simulations for argon-like particles and n-octane molecules. The simulations confirm the integral relations within the accuracy of the calculation for both systems. Evidence is presented for the existence of an excess thermal resistivity on the gas side of the surface, and the fact that this property is decisive for interface heat and mass transfer coefficients. The integral relations were used to predict the mass transfer coefficient for n- octane as a function of surface tension. The findings are important for modeling of one-component phase transitions.

Temozolomide as initial treatment for adults with low-grade oligodendrogliomas or oligoastrocytomas and correlation with chromosome 1p deletions

PURPOSE

To determine the response rate of low-grade oligodendroglial tumors (LGOT) to temozolomide (TMZ) as initial treatment and to evaluate the predictive value of chromosome 1p deletion on the radiologic response.

PATIENTS AND METHODS

Adult patients with pathologically proven LGOT with progressive disease on magnetic resonance imaging (MRI) were eligible for the study. TMZ was administered at the starting dose of 200 mg/m2/d for 5 days, repeated every 28 days. Response was evaluated clinically and by central review of MRIs. Chromosome 1p and 19q deletions were detected by the loss of heterozygosity technique.

RESULTS

Sixty consecutive patients were included in the study. At the time of analysis, the median number of TMZ cycles delivered was 11. Clinically, 51% of patients improved, particularly those with uncontrolled epilepsy. The objective radiologic response rate was 31% (17% partial response and 14% minor response), whereas 61% of patients had stable disease and 8% experienced disease progression. The median time to maximum tumor response was 12 months (range, 5 to 20 months). Myelosuppression was the most frequent side effect, with grade 3 to 4 toxicity in 8% of patients. Loss of chromosome 1p was associated with objective tumor response (P < .004).

CONCLUSION

TMZ is well tolerated and provides a substantial rate of response in LGOT. Chromosome 1p loss is correlated with radiographic response and could be a helpful marker for guiding therapeutic decision making in LGOT.

Immunoprophylaxis with Simulect (basiliximab) in pediatric kidney transplant recipients: results from routine clinical practice at 5 kidney transplant units

BACKGROUND

Simulect (basiliximab) was introduced in Spain in February 1999, being the first anti-interleukin-2 receptor monoclonal antibody used in our country for the prevention of acute rejection in kidney transplantation. The objective of this study was to assess the efficacy and safety of Simulect (basiliximab) in routine clinical practice in pediatric Spanish kidney transplantation units.

METHODS

In this prospective, observational study, we collected data related to demographics, parameters of efficacy, immunosuppressive therapy, and safety on kidney transplant patients treated with Simulect (basiliximab) using an on-line collection system.

RESULTS

Fifty pediatric patients at 5 kidney transplant units with 12 months follow-up included recipient mean age of 10.00 years (DS 5.40). Twenty-nine (58.00%) were boys and 21 (42.00%) were girls. Cold ischemia time was 15 hours and 50 minutes (DS 9.70 h). No patient presented with a PRA >50%. For prophylactic immunosuppression, 85.70% of patients received triple therapy with CNI (cyclosporine 48.97% or tacrolimus 36.73%), MMF (87.76%) or AZA (12.24%), and steroids. Acute rejection incidence at 12 months was 22%, including 3 steroid-resistant episodes (6%). One patient lost the graft (2%), 7 adverse events (AE) were reported (1 mild, 4 moderate, and 1 severe AE), of which none were attributed to the study drug.

CONCLUSIONS

Simulect (basiliximab) treatment of pediatric patients who underwent kidney transplantations performed in routine clinical practice showed good prophylaxis against acute rejection with excellent safety.

Influence of tamoxifen on carotid intima-media thickness in postmenopausal women

BACKGROUND

Intima-media thickness of the common carotid artery (IMT-CCA) is an early marker of atherosclerosis. Tamoxifen is a selective estrogen-receptor modulator with estrogen-like effects on cardiovascular risk factors but as-yet unexplored effects on carotid artery structure. The goal of this study was to determine the influence of tamoxifen on IMT-CCA in menopausal women.

METHODS AND RESULTS

With a predefined calculation of the sample size, 67 menopausal women with cancer who were treated with tamoxifen for > or =1 year and 37 menopausal women with cancer who were never treated with tamoxifen were enrolled. IMT-CCA, internal diameter, and pulse pressure were determined with a high-definition echotracking device and applanation tonometry in a central core laboratory that was blinded to treatment. Both groups were similar for clinical characteristics, including cardiovascular risk factors. IMT and internal diameter were significantly lower in the tamoxifen group (mean duration of treatment, 2.4+/-0.9 years) than in the control group (609+/-117 microm versus 662+/-147 microm, P=0.04, and 4.89+/-0.60 mm versus 5.12+/-0.58 mm, P=0.03, respectively). Pulse pressure was not influenced by the use of tamoxifen. After adjustment for age, cardiovascular risk factors, carotid pulse pressure, duration of menopause, and previous use of hormone replacement therapy, IMT remained significantly lower among tamoxifen users (P<0.00001), with an impact on IMT (-70 microm) equivalent to spontaneous evolution with 12 years of aging (5 microm/y).

CONCLUSION

The use of tamoxifen was associated with a significantly lower carotid IMT in menopausal women with cancer. Randomized trials are needed to confirm the cardioprotective effect of selective estrogen-receptor modulators in terms of prevention of atherosclerosis.

[Comparison with dose-volume histograms of two conformal irradiation techniques used for the treatment of T2N0M0 nasopharyngeal cancer, one with association of photons and protons and another with photons alone]

Purpose- There is a relationship between the local control rate of the nasopharyngeal cancer and the total dose delivered within the tumoral volume. In contrast, the relation between the dose and the irradiated volume and the risk of complication is not clearly defined. That is why, in patients presenting with a locally advanced nasopharyngeal cancer, we compared the dose-volume distribution of irradiated tissues, obtained from two 3D conformal irradiation techniques. Patients and methods- Between January 2000 and June 2001, 5 patients, 3 males and 2 females, with a median age of 32 years and presenting with a T4N0M0 nasopharyngeal cancer received a chemoradiotherapy. Radiotherapy combined photons and protons beams and the platin-based chemotherapy was delivered in three intravenous injections at d1, 22, 43 of the irradiation. To calculate the dosimetry, a CT scan and a MRI were performed in all the patients. The gross tumor volume (GTV) was delineated from the imagery, three clinical tumor volumes were defined, the CTV1 was the GTV and the whole nasopharynx, the CTV2 was the CTV plus a 10 mm-margin and the CTV3 was the CTV2 and the nodes areas (cervical and subclavicular). Prophylactic dose within node areas was 44 Gy. Prescribed doses within CTV2 and GTV or CTV1 were 54 Gy/CGE (Cobalt Gy Equivalent, for an EBR = 1,1) and 70 Gy/CGE, respectively. Irradiation was delivered with fractions of 1.8 or 2.0 Gy/CGE, with 44 Gy or 54 Gy by photons and with 16 or 26 CGE by protons. According to dose-volume histograms obtained from the dosimetry planning by protons and photons and from the theoretical dosimetry by photons lonely, for the different volumes of interest, GTV, CTV2, and organs at risk (optic nerves, chiasm, internal ears, brainstem, temporal lobes), we compared the averages of the maximum, minimum and mean doses and the averages of the volumes of organs of interest encompassed by different isodoses.Results- Calculated averages of minimum, maximum and mean doses delivered within GTV were superior for the treatment with combined photons and protons than with photons alone. The average GTV encompassed by the 70 Gy/CGE isodose was larger by 65% with the association compared to photons alone. The conformation ratio (tissue volume encompassed by the 95% isodose/GTV encompassed by the 95% isodose) was 3.1 with the association compared to 5.7 with photons alone. For the CTV2, there were no differences in different criteria according to the both irradiation techniques. For the critical, radiosensitive organs, the comparison of the majority of the criteria was in favour of the association of protons and photons. Overall, 78% of the criteria were in favour of the association.Conclusion- For locally advanced nasopharyngeal cancer without clinical adenopathy, irradiation by photons and protons increases the tumor volume irradiated at the prescribed dose and decreases the volume or critical organs irradiated and the total dose delivered within them.

[Target-volume and critical-organ delineation for conformal radiotherapy of prostate cancer: experience of French dose-escalation trials]

The delineation of target volume and organs at risk depends on the organs definition, and on the modalities for the CT-scan acquisition. Inter-observer variability in the delineation may be large, especially when patient's anatomy is unusual. During the two french multicentric studies of conformal radiotherapy for localized prostate cancer, it was made an effort to harmonize the delineation of the target volumes and organs at risk. Two cases were proposed for delineation during two workshops. In the first case, the mean prostate volume was 46.5 mL (extreme: 31.7-61.3), the mean prostate and seminal vesicles volume was 74.7 mL (extreme: 59.6-80.3), the rectal and bladder walls varied respectively in proportion from 1 to 1.45 and from 1 to 1.16; in the second case, the mean prostate volume was 53.1 mL (extreme: 40.8-73.1), the volume of prostate plus seminal vesicles was 65.1 mL (extreme: 53.2-89), the rectal wall varied proportionally from 1 to 1, 24 and the vesical wall varied from 1 to 1.67. For participating centers to the french studies of dose escalation, a quality control of contours was performed to decrease the inter-observer variability. The ways to reduce the discrepancies of volumes delineation, between different observers, are discussed. A better quality of the CT images, use of urethral opacification, and consensual definition of clinical target volumes and organs at risk may contribute to that improvement.

[Intracerebral radiotherapy under stereotaxic conditions]

Stereotactic radiosurgery is used for treating several brain diseases. Radiosurgery is a non-invasive alternative to surgery for brain metastases, and randomized trials are on going to assess the role of radiosurgery. Radiosurgery has been advocated for patients with small benign meningioma or with vestibular schwannoma, but there is no proof of efficacy and safety of radiosurgery in comparison with other treatments. Radiosurgery can obliterate 80-90% of small arteriovenous malformations, but no information exists on the survival of treated compared with untreated patients. The limited information available suggests that radiosurgery should be fully evaluated in well-designed prospective studies.

[Gross tumor volume and clinical target volume in radiotherapy: bone metastasis]

Bone is one of the three most favored sites of solid tumor metastasis. Skeletal metastasis may be identified by four clinical imaging methods: plain film radiography, computed tomography scanning, radioisotope scanning, and magnetic resonance imaging. The dose per fraction, total dose, and anatomic distribution of the radiation (dosimetry) are important factors in determining the efficacy and normal tissue tolerance to radiotherapy. Controversies about fractionation of palliative radiotherapy for bone metastasis are steel ongoing. The most commonly used schedules are a single treatment of 8 Gy, 30 Gy in 10 fractions and 20 Gy in 5 fractions. Treatment volumes and safety margins depend on the location and the extent of the bone metastasis, and are also determined by the symptoms felt by the patient.

Shifting of localization planes in optical testing: application to a shearing interferometer

An amplitude-division two-beam interferometer illuminated by a quasi-monochromatic, spatially incoherent, and periodic source yields multiple localization planes of interference fringes. If a thick transmission sample with a few localized phase disturbances in various layers is placed in the interferometer, the disturbances in a layer can be detected, making its images through the two arms coincide with a chosen localization plane. Different layers can be analyzed by means of shifting the localization plane by a variation of the source period without any other changes in the device. Here we illustrate this method by applying it to a shearing interferometer, a classical Wollaston prism placed between crossed polarizers. Experimental images of different observation planes are obtained, and they are in good agreement with the theoretical expectations.

Radiosurgery for re-irradiation of brain metastasis: results in 54 patients

PURPOSE

To evaluate in terms of probabilities of local-regional control and survival, as well as of treatment-related toxicity, results of radiosurgery for brain metastasis arising in previously irradiated territory.

PATIENTS AND METHODS

Between January 1994 and March 2000, 54 consecutive patients presenting with 97 metastases relapsing after whole brain radiotherapy (WBRT) were treated with stereotactic radiotherapy. Median interval between the end of WBRT and radiosurgery was 9 months (range 2-70). Median age was 53 years (24-80), and median Karnofski performance status (KPS) 70 (60-100). Forty-seven patients had one radiosurgery, five had two and two had three. Median metastasis diameter and volume were 21 mm (6-59) and 1.2 cc (0.1-95.2), respectively. A Leksell stereotactic head frame (Leksell Model G, Elektra, Instrument, Tucker, GA) was applied under local anesthesia. Irradiation was delivered by a gantry mounted linear accelerator (linacs) (Saturne, General Electric). Median minimal dose delivered to the gross disease was 16.2 Gy (11.8-23), and median maximal dose 21.2 Gy (14- 42).

RESULTS

Median follow-up was 9 months (1-57). Five metastases recurred. One- and 2-year metastasis local control rates were 91.3 and 84% and 1- and 2-year brain control rates were 65 and 57%, respectively. Six patients died of brain metastasis evolution, and three of leptomeningeal carcinomatosis. One- and 2-year overall survival rates were 31 and 28%, respectively. According to univariate analysis, KPS, RPA class, SIR score and interval between WBRT and radiosurgery were prognostic factors of overall survival and brain free-disease survival. According to multivariate analysis, RPA was an independent factor of overall survival and brain free-disease survival, and the interval between WBRT and radiosurgery longer than 14 months was associated with longer brain free-disease survival. Side effects were minimal, with only two cases of headaches and two of grade 2 alopecia.

CONCLUSION

Salvage radiosurgery of metastasis recurring after whole brain irradiation is an effective and accurate treatment which could be proposed to patients with a KPS>70 and a primary tumour controlled or indolent. We recommend that a dose not exceeding 14 Gy should be delivered to an isodose representing 70% of the maximal dose since local control observed rate was similar to that previously published in literature with upper dose and side effects were minimal.

[Radiotherapy of brain astrocytomas and oligodendrogliomas of the adult]

Gliomas are moderately radiosensitive. The main prognostic factors are the anatomicopathological type and grade of glioma, the performance status, age of the patient and the extent of the surgery. According to data from the literature, high-grade gliomas should be given 60 Gy in five weekly fractions of 1.7 to 2 Gy in a volume including tumor or tumor bed, edema and a 2- to 3-cm margin. A dose of 45 Gy would be sufficient for low-grade gliomas, according to the results of a recent randomized EORTC trial. Brachytherapy and radiosurgery techniques may be indicated in selected cases.

Multilocalization and the van Cittert-Zernike theorem. 2. Application to the Wollaston prism

The van Cittert-Zernike theorem can be used to evaluate visibility at the exit of an amplitude-division interferometer with two-beam interferences. If the source illuminating the interferometer is a periodic array of slits, at the exit there is a sequence of localization surfaces. The formulas for the position and fringe spacing of the principal localization surfaces are applied to a Wollaston quartz prism, and there is good agreement between theoretical and experimental results. Moreover, the fringe localization depth and the intermediate localization surfaces obtained experimentally coincide with those predicted by theory.

Multilocalization and the van Cittert-Zernike theorem. 1. Theory

The complex degree of coherence and the resulting van Cittert-Zernike theorem are employed to analyze the exit of an arbitrary amplitude-division interferometer with two-beam interferences. Considering that the source is a periodic array of spatially incoherent slits and assuming negligible equivalent aberrations and no vignetting, an expression for the complex degree of coherence as a function of the position of an exit point is derived. Formulas for the location, fringe spacing, and fringe localization depth of the multilocalized fringes are given.

Comparison of double-contrast CT arthrography image quality with nonionic contrast agents: isotonic dimeric iodixanol 270 mg I/mL and monomeric iohexol 300 mg I/mL

RATIONALE AND OBJECTIVES

The authors evaluated the image quality on delayed CT arthrography images with the use of the nonionic dimeric contrast agent, iodixanol 270 mg I/mL, compared with iohexol 300 mg I/mL.

METHODS

A total of 132 patients with shoulder pain were included in a randomized, parallel, double-blind study. Sixty seven patients received iodixanol and 65 patients received iohexol. Patients underwent two CT-arthrography examinations: the first was performed 20 to 30 minutes after contrast injection and the second, 50 to 70 minutes after contrast injection. Data from 31 patients were excluded from the efficacy analysis. The overall quality of CT arthrography images was graded into four categories: excellent, good, moderate, and bad.

RESULTS

The overall quality of delayed CT arthrography images was significantly better in the iodixanol group (P = 0.001, alpha = 0.05). On the first CT examination, image quality was good or excellent in 88% of the cases in the iodixanol group and in 96.1% in the iohexol group. The results on the delayed CT arthrography examination indicated that image quality was good or excellent in 88% of the cases when iodixanol was used and in 63.5% when iohexol was used.

CONCLUSIONS

The overall quality of delayed images was significantly better with iodixanol than with iohexol.

[A quality reference manual for radiology]

The purpose of this article is to introduce a quality manual for radiology departments. A radiology department has implemented a quality improvement program since 1996. This manual was developed as a tool for quality improvement program. This manuscript, was based on foreign accreditation manuals as well as from French experiences and summarized. In addition, new criteria were added, especially in the field of interventional radiology. This reference book is first dedicated to the self-assessment of radiology departments. It can also be used for an external audit.

Treatment of malignant gliomas in the elderly

The benefit of standard treatment of malignant glioma in older patients is debated. In order to assess the effect of a combination of surgery, radiotherapy and chemotherapy on survival of elderly patients with high grade gliomas, 30 consecutive patients older than 70 years with malignant supratentorial gliomas were studied between 9/93 and 9/96. Median age was 73 years (70-79). The mean Karnofsky performance status (KPS) was 66 (30-100). Patients underwent maximum possible surgery, followed by a course of radiotherapy (45 Gy/25 fractions/5 weeks) with 3 or 4 orthogonal beams and a 2 cm margin around the tumor bed. The administration of chemotherapy was left at the discretion of the responsible physician and 12 patients received reduced dose nitrosourea-based chemotherapy. The overall median survival was 36 weeks. The median time to progression was 26 weeks. Three months after surgery, 26 patients were alive, 5 were in complete response, 2 in partial response and 10 were stabilized. Preradiotherapy KPS was the only significant prognostic factor with a median survival of 40 weeks in patients with KPS > or = 70 and 25 weeks when KPS was < 70 (logrank test, p = 0.05). In responding and stable patients (57% of the group) the median KPS was 68 and 66 at 1 and 3 months after the completion of radiotherapy. There was no case of radiotherapy-induced dementia with this regimen. Four out of 12 patients who received chemotherapy, experienced WHO grade 3/4 hematotoxicity. This study suggest that some patients older than 70 years with KPS > or = 70 may benefit from the treatment of malignant gliomas with surgery followed by reduced dose of limited field radiotherapy. Further studies are needed to define the most appropriate dose of radiotherapy and to evaluate further the risk/benefit ratio of a reduced dose chemotherapy in this population.

How to optimize therapeutic ratio in brachytherapy of head and neck squamous cell carcinoma?

Considerable experience has been accumulated with low dose rate (LDR) brachytherapy in the treatment of squamous cell carcinoma of the oral cavity and oropharynx, 4 cm or less in diameter. Recent analysis of large clinical series provided data indicating that modalities of LDR brachytherapy should be optimized in treating these tumours for increasing therapeutic ratio. LDR brachytherapy is now challenged by high dose rate (HDR) brachytherapy and pulsed dose rate (PDR) brachytherapy. Preliminary results obtained with the last two modalities are discussed in comparison with those achieved with LDR brachytherapy.

Assessment of the superior labrum of the shoulder joint with CT-arthrography and MR-arthrography: correlation with anatomical dissection

The ability to detect and categorize SLAP (Superior Labrum Anterior to Posterior) lesions of the scapular labrum is of practical importance to the orthopedic surgeon and the radiologist. The aim of this study, performed on cadaveric shoulders, was to determine whether CT arthrography or MR arthrography is able to show normal anatomical variation of the glenoid labrum and detect labral abnormalities. CT arthrography, MR arthrography followed by anatomical dissection were performed on twenty three fresh frozen cadaveric shoulders and analysed by a radiologist and two orthopaedic surgeons. As Gadolinium intra-articular injection is not allowed in France, we used an iodinated contrast media for both MR arthrography and CT arthrography. In this study, the sensitivity of MR arthrography seemed higher than CT arthrography (respectively 4 and 3 labral lesions diagnosed out of five), although no significant statistical conclusions can be made due to the small number of cases. In conclusion, under such specific conditions, MR arthrography seems to be the method of choice for the detection and classification of labral lesions.

[Brachytherapy in France in 1995. Final results of the national survey]

A survey questionnaire was sent to the 189 French departments of radiation Oncology and 166 responded by brachytherapy and 358 shielded rooms were available. In Low Dose Rate (LDR) 81 departments used Cesium sources (159 afterloaders, 1,060 sources). Iridium wires were used by 84 departments (673 meters used). Only six departments used other elements. Twenty-six departments were equipped with high dose rate after loaders (HDR) all of them also using LDR techniques for most of the patients. A total of 9,160 patients were treated: 7,868 with LDR and 1,292 with HDR. The common sites treated by LDR were uterovaginal (4,300), breast (1,415), head and neck (1,049), skin (610), anorectal (220) and urologic (70). HDR was used for vaginal cuff (628), bronchi (371), oesophagus (232). PDR just started (33 patients) for a feasibility trial. The rate of patients treated by brachytherapy is around 6-8% of the irradiated patients, but the indications vary is each department. The diffusion of the techniques, and new indications should increase the number of patients being treated by brachytherapy.

[Importance of radiotherapy in stereotactic conditions (radiosurgery) in brain metastasis: experience and results of the Hôpital Pitié-Salpêtrière Group]

PURPOSE

Retrospective analysis of the influence of clinical and technical factors on local control and survival after radiosurgery for brain metastasis.

PATIENTS AND METHODS

From January 1994 to December 1996, 42 patients presenting with 71 metastases underwent radiosurgery for brain metastasis. The median age was 56 years and the median Karnofsky index 80. Primary sites included: lung (20 patients), kidney (seven), breast (five), colon (two), melanoma (three), osteosarcoma (one) and it was unknown for three patients. Seventeen patients had extracranial metastasis. Twenty-four patients were treated at recurrence which occurred after whole brain irradiation (12 patients), surgical excision (four) or after both treatments (eight). Thirty-six sessions of radiosurgery have been realized for one metastasis and 13 for two, three or four lesions. The median metastasis diameter was 21 mm and the median volume 1.7 cm3. The median peripheral dose to the lesion was 14 Gy, and the median dose at the isocenter 20 Gy.

RESULTS

Sixty-five metastases were evaluable for response analysis. The overall local control rate was 82% and the 1-year actuarial rate was 72%. In univariate analysis, theoretical radioresistance (P = 0.001), diameter less than 3 cm (P = 0.039) and initial treatment with radiosurgery (P = 0.041) were significantly associated with increased local control. Only the first two factors remained significant in multivariate analysis. No prognostic factor of overall survival was identified. The median survival was 12 months. Six patients had a symptomatic oedema (RTOG grade 2), only one of which requiring a surgical excision.

CONCLUSION

In conclusion, 14 Gy delivered at the periphery of metastasis seems to be a sufficient dose to control most brain metastases, with a minimal toxicity. Better results were obtained for lesions initially treated with radiosurgery, theoretically radioresistant and with a diameter less than 3 cm.

[Radiotherapy of glioblastoma]

Glioblastoma cells appear to be inherently radioresistant and to present a significant fraction of hypoxic cells. The most significant prognostic factors to compare results achieved in several series of patients are the age, performance status and quality of surgical resection. Several randomized trials have provided evidence supporting the efficacy of radiation therapy in the treatment of glioblastoma. Prescription of a 60-Gy dose delivered according to a conventional dose-fractionation scheme (single daily fractions of 1.7 to 2 Gy five times per week) in a target volume with a 2-3 cm margin of tissue surrounding the perimeter of the contrast enhancing lesion on computerized tomography and magnetic resonance imaging is derived from observations made in several retrospective and prospective studies. Evidence of improvement in survival was observed neither in patients receiving hyperfractioned and accelerated radiotherapy, nor in patients for whom radiation sensitizers such as nitroimidazole compounds or halogenated pyrimidine analogs were associated to radiation therapy. The addition of nitrosourea to radiotherapy increases the 2-year survival rate by about 10%. Combination of full-dose external beam radiotherapy and brachytherapy or radiosurgery boost in selected patients with glioblastoma leads to an increase in the median survival, while external beam radiation alone in patients with similar prognosis does not.

Combined percutaneous antegrade and cystoscopic retrograde ureteral stent placement: an alternative technique in cases of ureteral discontinuity

We describe an alternative method of double J stent placement for ureteral transection following the failure of traditional antegrade and retrograde approaches. Cystoscopically, a guidewire was placed across the distal ureteral segment and was advanced into a urinoma cavity at the level of the transected ureter. Subsequently, an antegrade approach was used to place a gooseneck snare through the proximal ureteral segment into the urinoma cavity. The guidewire was grasped with the snare and pulled through the percutaneous access site. A double J ureteral stent was then placed using the typical antegrade method.

[Postoperative radiotherapy in non-small cell lung cancer. Apropos of a series of 374 cases]

PURPOSE

Several randomized trials have led us to address the usefulness of post-surgical external beam therapy (EBT) in non-oat cell bronchial carcinoma. Results that were obtained in a group of 374 patients submitted between 1977 and 1994 to identical therapy-the follow-up being done by the same team-and results of six randomized trials are analyzed.

PATIENTS AND METHODS

The tumor stages were the following: T1, 13%; T2, 56%; T3, 29%; and T4, 2%; N0, 31%; N1, 34%; and N2, 35%. There were 85% histologically complete resections. EBT was administered according to either the classical irradiation scheme (C) or as an 'equivalent hypofractionated dose' (H) in the case of complete resection. When resection was not complete, 60 to 65 Gy were administered according to a C or an H irradiation scheme. The irradiation scheme was C in 73% of the cases and H in 27%. The EBT technique has been chosen to ensure maximum lung sparing. Following a 45 Gy-irradiation with anteroposterior beams, orthogonal or, when necessary, oblique beams were used. Non homogeneity of the lungs was taken into account in establishing the treatment planning. The treatment file was collectively checked by the medical staff in 75% of the cases. EBT was indicated for N+(N1+N2), T3 and incomplete resections.

RESULTS

The overall survival was 42% at 5 years and 27% at 10 years. The 5-year survival was 52% for stage I cancer (T1N0-T2N0), 60% for stage II cancer (T1N1-T2N1), 31% for stage IIIa cancer (T3N0, T1-3N2), 45% for complete resection and 30% when resection was not complete.

CONCLUSION

Regarding the benefits of post-surgical radiotherapy, the analysis of the six randomized trials does not allow any conclusion. This might be due to either the insufficient number of cases, a follow-up time not long enough, incorrect radiotherapy, or insufficient available data. Comparison of the results pertaining to the six trials with those of our series shows an advantage for the current series, indicating that survival is likely to be improved if EBT is correctly done with regard to the dose, volume and technique used.

Pain management knowledge of hospital-based nurses in a rural Appalachian area

The American Pain Society cites the failure of health care providers to routinely assess pain and pain relief as the most common reason for unrelieved pain in US hospitals. Lack of knowledge on the part of nurses about pain and its treatment is one of the major barriers to achieving comfort for those in pain. Thus, the purpose of this descriptive study was to determine the pain management knowledge of hospital-based nurses in a rural Appalachian area. The nonpurposive sample consisted of 123 registered nurses. The questionnaire consisted of three sections: demographic items and two instruments designed to measure knowledge of opioid classification and pain management. The overall pain management knowledge score was 67.4%. The findings indicate a knowledge deficit specifically related to the behavioural indicators of pain, classification of opioid analgesics, properties of opioid analgesics and adjuvant medications, and incidence of addiction. This sample of rural nurses demonstrates similar pain management knowledge compared to the reported scores of urban nurses. These results may serve as the impetus to develop strategies to decrease the barriers to effective pain management. Further education about pain management is warranted.

Spinal metastases: indications for and results of percutaneous injection of acrylic surgical cement

PURPOSE

To determine the efficacy of percutaneous vertebroplasty in treating spinal metastases that result in pain or instability.

MATERIALS AND METHODS

Thirty-seven patients (20 men, 17 women; aged 33-86 years) underwent 52 percutaneous injections of surgical cement into a vertebra (vertebroplasty) with fluoroscopic guidance in 40 procedures. Vertebroplasty was performed for analgesia in 29 procedures, stabilization of the vertebral column in five procedures, and both in six procedures.

RESULTS

Twenty-four of the 33 procedures performed for analgesia that were evaluated resulted in clear improvement; seven, moderate improvement; and two, no improvement. Improvement was stable in 73% of patients at 6 months. In the procedure performed for stabilization, no displacement of treated vertebrae was observed (mean follow-up, 13 months). Three patients had transient radiculopathy due to cement extrusion, and two patients had transient difficulty in swallowing.

CONCLUSION

Vertebroplasty of metastases is a minimally invasive procedure that provides immediate and long-term pain relief and contributes to spinal stabilization.

Design of a holographic optical element for a pulse compressor

Nonlinear chirped pulse compression can be theoretically achieved to any order by using a nonplane grating with adequate groove spacing. We evaluate the holographic recording of a grating that compensates to the quadratic chirp. A suitable design is found, and the building tolerances are analyzed.