Tunable four-wave mixing enabled by a self-phase modulation of chirped pulses

We experimentally demonstrate how a concatenation of the standard and microstructure fiber segments permits adjusting the four-wave mixing sideband position over a large spectral range by varying the chirp of an input pulsed pump at a fixed wavelength in the presence of a self-phase modulation. The blue- and redshifted sidebands can stand aside over ∼200 nm and ∼450 nm from the pump, respectively, which agrees well with the numerical simulations. We validate our approach by showing the feasibility of CARS imaging.

Three octave visible to mid-infrared supercontinuum generation seeded by multimode silica fiber pumped at 1064 nm

Hyperspectral spectroscopy requires light sources with wide spectral ranges from the visible to the mid-infrared. Here, we demonstrate the first fiber-based mid-infrared supercontinuum covering three octaves of frequency by leveraging 1-µm laser technology. The process consists in spectral broadening of a 1064-nm pump toward 0.48-2.5 µm in a graded-index multimode fiber, followed by a fluoro-indate fiber used to reach deeper into the near infrared (4.3 µm). Finally, an arsenic selenide chalcogenide fiber allows us to reach the 6-µm wavelength region, providing a 0.75-6-µm supercontinuum. We illustrate the potential of this light source by recording mid-infrared absorption spectra of organic compounds.

Observation of Light Thermalization to Negative-Temperature Rayleigh-Jeans Equilibrium States in Multimode Optical Fibers

Although the temperature of a thermodynamic system is usually believed to be a positive quantity, under particular conditions, negative-temperature equilibrium states are also possible. Negative-temperature equilibriums have been observed with spin systems, cold atoms in optical lattices, and two-dimensional quantum superfluids. Here we report the observation of Rayleigh-Jeans thermalization of light waves to negative-temperature equilibrium states. The optical wave relaxes to the equilibrium state through its propagation in a multimode optical fiber-i.e., in a conservative Hamiltonian system. The bounded energy spectrum of the optical fiber enables negative-temperature equilibriums with high energy levels (high-order fiber modes) more populated than low energy levels (low-order modes). Our experiments show that negative-temperature speckle beams are featured, in average, by a nonmonotonic radial intensity profile. The experimental results are in quantitative agreement with the Rayleigh-Jeans theory without free parameters. Bringing negative temperatures to the field of optics opens the door to the investigation of fundamental issues of negative-temperature states in a flexible experimental environment.

Continuous spatial self-cleaning in GRIN multimode fiber for self-referenced multiplex CARS imaging

We demonstrate how spatial beam self-cleaning and supercontinuum generation in graded-index multimode optical fibers can be directly applied in multiplex coherent anti-Stokes Raman Scattering (M-CARS) spectroscopy. Although supercontinuum generation causes pump depletion mainly in the center of the beam, the partial recovery of the pump brightness due to self-cleaning may enable self-referenced M-CARS, with no additional delay lines to synchronize pump and Stokes waves. As a proof-of-principle, we report examples of imaging of single chemical compounds and polystyrene beads. The new scheme paves the way towards simpler M-CARS systems based on multimode fiber sources.

Frequency-resolved spatial beam mapping in multimode fibers: application to mid-infrared supercontinuum generation

We present a new, to the best of our knowledge, spatial-spectral mapping technique permitting measurement of the beam intensity at the output of a graded-index multimode fiber (GIMF) with sub-nanometric spectral resolution. We apply this method to visualize the fine structure of the beam shape of a sideband generated at 1870 nm by geometric parametric instability (GPI) in a GIMF. After spatial-spectral characterization, we amplify the GPI sideband with a thulium-doped fiber amplifier to obtain a microjoule-scale picosecond pump whose spectrum is finally broadened in a segment of InF₃ optical fiber to achieve a supercontinuum ranging from 1.7 up to 3.4 µm.

Correlation of morphological and radiological characteristics of degenerative disc disease in lumbar spine: a cadaveric study

BACKGROUND

Intervertebral disc (IVD) degeneration plays a crucial role in the pathophysiology of low back pain. Several grading systems have been developed for both morphological and radiological assessment. The aim of this study was to assess the morphological and radiological characteristics of IVD degeneration and validate popular radiological Pfirrmann scale against morphological Thompson grading system.

MATERIAL AND METHODS

Full spinal columns (vertebrae L1-S1 and IVD between them) were harvested from cadavers through an anterior dissection. MRI scans of all samples were conducted. Then, all vertebral columns were cut in the midsagittal plane and assessed morphologically.

RESULTS

A total of 100 lumbar spine columns (446 IVDs) were included in the analysis of the degeneration grade. Morphologic Thompson scale graded the majority of discs as grade 2 and 3 (44.2% and 32.1%, respectively), followed by grade 4 (16.8%), grade 1 (5.8%) and grade 5 (1.1%). The Radiologic Pfirrmann grading system classified 44.2% of discs as grade 2, 32.1% as grade 3, 16.8% as grade 4, 5.8% as grade 1 and 1.1% as grade 5. The analysis on the effect of age on degeneration revealed significant, although moderate, positive correlation with both scales. Analysis of the agreement between scales showed weighted Cohen's kappa equal to 0.61 (p<0.001). Most of the disagreement occurred due to a 1 grade difference (91.5%), whereas only 8.5% due to a 2 grade difference.

CONCLUSIONS

With the increase of the prevalence of intervertebral disc disease in the population, reliable grading systems of IVD degeneration are crucial for spine surgeons in their clinical assessment. While overall there is agreement between both grading systems, clinicians should remain careful when using Pfirmann scale as the grades tend to deviate from the morphological assessment.

Optimum design of NOLM-driven mode-locked fiber lasers

Most of the saturable absorbers commonly used to perform mode locking in laser cavities affect the trigger conditions of laser oscillation, which requires manually forcing the laser start-up by various means such as polarization controllers. We present a procedure for designing a laser cavity driven by a nonlinear optical loop mirror, which allows the laser to operate optimally without interfering with the oscillation triggering conditions, thus opening up possibilities for integration of this type of laser.

Abstract PS1-46: Magnetic seeds to aid targeted axillary dissection

Introduction: Indications for accurate removal of a previously identified, involved or highly suspicious axillary lymph node include: 1) after neoadjuvant chemotherapy (NACT) to ensure pathological assessment of the correct index node (targeted axillary dissection, TAD) 2) for women with an abnormal/indeterminate node on imaging who may be able to avoid axillary lymph node clearance (ALNC) because they meet Z0011 criteria or may be eligible for POSNOC trial inclusion 3) guided removal of a specific axillary lymph node (eg Rotter’s node recurrence, diagnostic biopsy, inclusion of specific node in ALNC). Dual localisation is either not viable or has an unacceptably high false negative rate in these scenarios and marking of the index node is advised. Although conventional markers are often used prior to NACT, finding that marked node at surgery can pose a challenge. Wire localisation has variable outcomes and scheduling constraints. Magnetic seed localisation, with MagseedTM, allows for easy placement and excision of targeted nodes. Seeds can be accurately placed, do not migrate and can now be placed many months prior to surgery, at the start of NACT. The aim of this study was to report our early experience. Methods: Patients were identified by searching an imaging database for women who had undergone ultrasound (US)-guided MagseedTM insertion into an abnormal axillary lymph node between August 2018 and July 2020. Data on intended use and surgical outcomes were collected retrospectively from electronic patient records (EPR). Patients were categorised into 3 groups as described above. Results: 37 patients were identified, 17 in group 1, 13 in group 2 and 7 in group 3. Only 1 patient had complications with MagseedTM insertion, requiring a second attempt to successfully mark the required node. In 1 patient the MagseedTM was found on the surgical drape, thought to have been lying adjacent to the node intended for excision, this patient was therefore excluded from further evaluation in the results, as were 3 patients with missing data. One patient has yet to come to surgery, all other MagseedsTM have been successfully retrieved. Group 3 indications were disparate, and this group will not be described further. Group 1 - in 10 of 15 patients post NACT the MagseedTM-marked node was found to be the sentinel node by routine mapping techniques (Technetium 99 +/- Patent V blue dye injection), identified as either hot or hot and blue. Of the 15 patients, 6 remained node positive on intra-operative assessment and underwent ALNC whilst 9 (60%) were spared ALNC. 2 patients avoided false negative results as the Magseed™-marked node contained residual disease yet was neither hot nor blue. Group 2 - Ten patients underwent sentinel lymph node biopsy using routine mapping techniques and MagseedTM-guided excision of a specifically targeted node. In 7 the MagseedTM-marked node was found to be a sentinel node (hot or hot and blue). Only 3 patients had sufficient disease to warrant completion ALNC. Conclusion: Insertion of a magnetic seed into a biopsy-proven positive node prior to planned TAD or into an abnormal node identified at diagnosis facilitates specific node retrieval for pathological assessment, with minimal associated complications, and has wide versatility. Magnetic seed localisation reduces the false negative rate and provides confidence in the correct assessment of the axilla thereby sparing patients unnecessary ALNC if they have had a complete pathological response to NACT or have limited axillary disease. The ability to insert the seed prior to the surgical date allows for flexibility with scheduling in comparison to wire localisation.

Citation Format: Kathryn E Harborough, V Sinnett, K Downey, K Krupa, J E Rusby, P A Barry. Magnetic seeds to aid targeted axillary dissection [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-46.

3D time-domain beam mapping for studying nonlinear dynamics in multimode optical fibers

Characterization of the complex spatiotemporal dynamics of optical beam propagation in nonlinear multimode fibers requires the development of advanced measurement methods, capable of capturing the real-time evolution of beam images. We present a new space-time mapping technique, permitting the direct detection, with picosecond temporal resolution, of the intensity from repetitive laser pulses over a grid of spatial samples from a magnified image of the output beam. By using this time-resolved mapping, we provide, to the best of our knowledge, the first unambiguous experimental observation of instantaneous intrapulse nonlinear coupling processes among the modes of a graded index fiber.

Classical Rayleigh-Jeans Condensation of Light Waves: Observation and Thermodynamic Characterization

Theoretical studies on wave turbulence predict that a purely classical system of random waves can exhibit a process of condensation, which originates in the singularity of the Rayleigh-Jeans equilibrium distribution. We report the experimental observation of the transition to condensation of classical optical waves propagating in a multimode fiber, i.e., in a conservative Hamiltonian system without thermal heat bath. In contrast to conventional self-organization processes featured by the nonequilibrium formation of nonlinear coherent structures (solitons, vortices,…), here the self-organization originates in the equilibrium Rayleigh-Jeans statistics of classical waves. The experimental results show that the chemical potential reaches the lowest energy level at the transition to condensation, which leads to the macroscopic population of the fundamental mode of the optical fiber. The near-field and far-field measurements of the condensate fraction across the transition to condensation are in quantitative agreement with the Rayleigh-Jeans theory. The thermodynamics of classical wave condensation reveals that the heat capacity takes a constant value in the condensed state and tends to vanish above the transition in the normal state. Our experiments provide the first demonstration of a coherent phenomenon of self-organization that is exclusively driven by optical thermalization toward the Rayleigh-Jeans equilibrium.

Highly efficient few-mode spatial beam self-cleaning at 1.5µm

We experimentally demonstrate that spatial beam self-cleaning can be highly efficient when obtained with a few-mode excitation in graded-index multimode optical fibers. By using 160 ps long, highly chirped (6 nm bandwidth at -3dB) optical pulses at 1562 nm, we demonstrate a one-decade reduction of the power threshold for spatial beam self-cleaning, with respect to previous experiments using pulses with laser wavelengths at 1030-1064 nm. Self-cleaned beams remain spatio-temporally stable for more than a decade of their peak power variation. The impact of input pulse temporal duration is also studied.

Spatial beam self-cleaning and supercontinuum generation with Yb-doped multimode graded-index fiber taper based on accelerating self-imaging and dissipative landscape

We experimentally demonstrate spatial beam self-cleaning and supercontinuum generation in a tapered Ytterbium-doped multimode optical fiber with parabolic core refractive index profile when 1064 nm pulsed beams propagate from wider (122 µm) into smaller (37 µm) diameter. In the passive mode, increasing the input beam peak power above 20 kW leads to a bell-shaped output beam profile. In the active configuration, gain from the pump laser diode permits to combine beam self-cleaning with supercontinuum generation between 520-2600 nm. By taper cut-back, we observed that the dissipative landscape, i.e., a non-monotonic variation of the average beam power along the MMF, leads to modal transitions of self-cleaned beams along the taper length.

Wavefront shaping for optimized many-mode Kerr beam self-cleaning in graded-index multimode fiber

We report experimental results, showing that the Kerr beam self-cleaning of many low-order modes in a graded-index multimode fiber can be controlled thanks to optimized wavefront shaping of the coherent excitation beam. Adaptive profiling of the transverse input phase was utilized for channeling the launched power towards a specific low-order fiber mode, by exploiting nonlinear coupling among all guided modes. Experiments were carried out with 7 ps pulses at 1064 nm injected in a five meters long multimode fiber operating in the normal dispersion regime. Optimized Kerr beam self-cleaning of five different LP modes is reported, with a power threshold that increases with the mode order.

Hydrodynamic 2D Turbulence and Spatial Beam Condensation in Multimode Optical Fibers

We show that Kerr beam self-cleaning results from parametric mode mixing instabilities that generate a number of nonlinearly interacting modes with randomized phases-optical wave turbulence, followed by a direct and inverse cascade towards high mode numbers and condensation into the fundamental mode, respectively. This optical self-organization effect is an analogue to wave condensation that is well known in hydrodynamic 2D turbulence.

Effect of exogenous butyrate on the gastrointestinal tract of sheep. I. Structure and function of the rumen, omasum, and abomasum

The aim of this study was to determine the effect of exogenous butyrate on the structure and selected functions of the stomach in sheep. Eighteen rams (30.8 ± 2.1 kg; 12 to 15 mo of age) were allocated to the study and fed a diet for 14 d without (CTRL) or with sodium butyrate (BUT; 36 g/kg of offered DM). Neither DMI nor initial BW differed between treatments (P ≥ 0.61), but final BW was greater for BUT compared with CTRL (P = 0.03). Butyrate concentration in the reticuloruminal fluid and abomasal digesta was greater for BUT compared with CTRL (P ≤ 0.01), but total short-chain fatty acids (SCFA) concentration, as well as concentration of other SCFA, did not differ between treatments (P ≥ 0.07). Relative to BW, reticuloruminal tissue mass tended (P = 0.09) to be greater and omasal digesta was less (P = 0.02) for BUT compared with CTRL. Dietary butyrate did not affect ruminal papillae length, width, and density nor did it affect ruminal epithelium thickness (P ≥ 0.12) in the ventral sac of the rumen. However, the DM of ruminal epithelium (mg/cm2) tended (P = 0.06) to be greater for BUT compared with CTRL. Omasal and abomasal epithelium thicknesses were greater (P ≤ 0.05) for BUT compared with CTRL. Mitosis-to-apoptosis ratio in the abomasal epithelium was less for BUT compared with CTRL (P = 0.04). Finally, the mRNA expression of peptide transporter 1 in the omasal epithelium was less (P = 0.02) and mRNA expression of monocarboxylate transporter 1 in the abomasal epithelium tended (P = 0.07) to be greater for BUT compared with CTRL. It can be concluded that exogenous butyrate supplementation affected not only the rumen but also omasum and abomasum in sheep.

Abstract P3-03-14: Clinical utility of one-step nucleic acid amplification (OSNA) in axillary surgery after neoadjuvant chemotherapy (NAC)

Introduction

NAC has been used for downsizing of the tumour in breast and axilla to allow more conservative surgery. In the NAC setting, intraoperative assessment of sentinel lymph node(s) (SLN) is still considered necessary1. Current awareness of the prognostic value for axillary nodal down-staging has renewed interest in analysis of SLN post-NAC.

In this study we want to examine the clinical utility of OSNA (based on CK19 mRNA detection) as a method of intra-operative analysis of SLN to assist real-time decision-making for axillary surgery post-NAC in early breast cancer (EBC).

Methods

Retrospective analysis of prospective data on 399 consecutive patients with EBC who received NAC followed by breast surgery with SLN biopsy (408 axillae) and assessment by OSNA, from September 2011 to January 2018 at the Royal Marsden Hospital (UK). OSNA readouts from the Sysmex RD-100i were collected separate to and blinded from clinico-pathological data. A negative or benign pre-treatment axillary ultrasound scan or indeterminate ultrasound with negative or benign axillary cytology/histology prior to NAC was considered cN0. Univariate analysis (significance at p&lt;0.05) was used to identify risk of recurrence. Patients had a median (mean) follow up of 32.5 (36) months.

Results

The median age at diagnosis was 49 years, median BMI 26, 41 EBC (10%) were screen-detected, 292 (72%) were grade 3 and the most frequent phenotype was receptor triple negative (n=132, 32%).

Of 408 axillae, 248 (60%) were initially cN0, of which 113 (46%) had a pathological complete response (pCR) in the breast. SLN in 54 (22%) cN0 patients were positive on OSNA, of which only 6 (9%) had further involved axillary nodes all 6 of which were ER+ Her2-.

The remaining 160 (40%) axillae were cN1 of which 87 (54%) had conversion to ypN0 including 55 (34%) with both ypT0ypN0.

Axillary lymphadenectomy (AL) was performed in 79 (19%) patients overall, of which n=22 (28%) were cN0 and 57 (72%) were cN1. Of these, 30 (53%) of the cN1 and 6 of 22 (45%) of cN0 had at least 1 additional positive AL node.

Overall 59 (14.4%) patients relapsed. A significantly worse rate of relapse was observed in cN1 compared to cN0 patients (37/159 (23.3%) versus 22/244 (9%), p&lt;0.001). Combined pCR of both breast and axilla (in cN1, n=54) was associated with a significantly reduced risk of relapse and death (p&lt;0.001) compared to those without pCR of either breast or axilla (n=62). Of the latter 18 (29%) relapsed (including 10 deaths).

The mean of both the single highest node tumour load (and total nodal tumour load), as measured by CK19mRNA copies/ul on OSNA, were significantly higher at 90,000 (98,300) for those who relapsed versus 23,100 (25,100) for those without relapse (p=0.027).

Conclusions

The OSNA assay is an accurate tool for axillary SLN analysis in patients after NAC and was helpful in intra-operative axillary management. OSNA reduces the need for a second surgery for AL in 20% of breast cancer patients with a positive-SLN after NAC and might offer additional prognostic value.

Reference

1. NCCN. National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology Breast Cancer.2016.Version 2.2016.

Citation Format: Muscara F, Christaki G, Richardson C, O'Connell R, Padmanabhan P, Warwick J, Lee Y, Smith I, Nerurkar A, Osin P, Krupa K, Rusby J, Roche N, Gui G, MacNeil F, Barry P. Clinical utility of one-step nucleic acid amplification (OSNA) in axillary surgery after neoadjuvant chemotherapy (NAC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-14.

Magnetically confined electron beam system for high resolution electron transmission-beam experiments

A novel experimental setup has been implemented to provide accurate electron scattering cross sections from molecules at low and intermediate impact energies (1-300 eV) by measuring the attenuation of a magnetically confined linear electron beam from a molecular target. High-resolution electron energy is achieved through confinement in a magnetic gas trap where electrons are cooled by successive collisions with N₂. Additionally, we developed and present a method to correct systematic errors arising from energy and angular resolution limitations. The accuracy of the entire measurement procedure is validated by comparing the N₂ total scattering cross section in the considered energy range with benchmark values available in the literature.

A process to describe radiation damage at the molecular level. Application to the 125I seeds in water

The correlation between the absorbed energy and the induced biological damage still has unclear aspects, especially in the low energy and low dose rate irradiation regimes. From the knowledge of the molecular-induced effects (dissociations), it would be possible to better understand the side effects of radiation, such as induced cancers or damage to healthy tissue. With this in view, this paper presents results of a simulation of a ¹²⁵I-seed treatment with an event-by-event MC code (LEPTS) specifically designed to account for the low energy secondary particle interactions, such as electron attachment, vibro-rotational and neutral dissociation interactions. This calculation allowed us to analyze the potential radiation damage not only in connection with the energy deposition, but also in terms of induced molecular dissociations by taking into account ionizing and non-ionizing dissociative processes. We propose that this description of the molecular level damage be the basis for nanodosimetric evaluations.

Interplay of Kerr and Raman beam cleaning with a multimode microstructure fiber

We experimentally study the competition between Kerr beam self-cleaning and Raman beam cleanup in a multimode air-silica microstructure optical fiber. Kerr beam self-cleaning of the pump is observed for a certain range of input powers only. Stokes Raman beam generation and cleanup lead to both depletion and degradation of beam quality for the pump. The interplay of modal four-wave mixing and Raman scattering in the infrared domain leads to the generation of a multimode supercontinuum ranging from 500 nm up to 1800 nm.

Nonlinear beam self-cleaning in a coupled cavity composite laser based on multimode fiber

We study a coupled cavity laser configuration where a passively Q-switched Nd:YAG microchip laser is combined with an extended cavity, including a doped multimode fiber. For appropriate coupling levels with the extended cavity, we observed that beam self-cleaning was induced in the multimode fiber thanks to nonlinear modal coupling, leading to a quasi-single mode laser output. In the regime of beam self-cleaning, laser pulse duration was reduced from 525 to 225 ps. We also observed a Q-switched mode-locked operation, where spatial self-cleaning was accompanied by far-detuned nonlinear frequency conversion in the active multimode fiber.

Intermodal modulational instability in graded-index multimode optical fibers

We report on the experimental observation of an intermodal noise-seeded modulational instability process (MI) taking place in the normal dispersion regime of a few-mode graded-index optical fiber. Strong power dependence of the MI spectra is observed, with a peak gain modulation frequency that scales as the square root of the injected light power. These observations are in excellent agreement with the predictions of a bimodal-MI model.

Far-detuned cascaded intermodal four-wave mixing in a multimode fiber

We demonstrate far-detuned parametric frequency conversion processes in a few mode graded-index optical fibers pumped by a Q-switched picosecond laser at 1064 nm. Through a detailed analytical and numerical analysis, we show that the multiple sidebands are generated through a complex cascaded process involving inter-modal four-wave mixing. The resulting parametric wavelength detuning spans in the visible down to 405 nm and in the near-infrared up to 1355 nm.

Kerr self-cleaning of pulsed beam in an ytterbium doped multimode fiber

We experimentally demonstrate that Kerr spatial self-cleaning of a pulsed beam can be obtained in an amplifying multimode optical fiber. An input peak power of 500 W only was sufficient to produce a quasi-single-mode emission from the double-clad ytterbium doped multimode fiber (YMMF) with non-parabolic refractive index profile. We compare the self-cleaning behavior observed in the same fiber with loss and with gain. Laser gain introduces new opportunities to achieve spatial self-cleaning of light in multimode fibers at a relatively low power threshold.

Second harmonic generation in multimode graded-index fibers: spatial beam cleaning and multiple harmonic sideband generation

We study experimentally and numerically the spectral and spatial dynamics of second harmonic generation in an all-optically poled multimode graded-index fiber. In contrast with poled single-mode fibers, in a multimode graded-index fiber a pump can generate a series of sharp sidebands around its second harmonic (SH) that originate from the sub-millimetric periodic evolution of the intensity at the fundamental frequency. The mutual interaction between the fundamental and its SH may also strongly affect the spatial distribution of guided light for both colors: when increasing the pump power, both fundamental and SH output beams evolve from disordered multimode speckles into two bell-shaped beams.

Spatiotemporal characterization of supercontinuum extending from the visible to the mid-infrared in a multimode graded-index optical fiber

We experimentally demonstrate that pumping a graded-index multimode fiber with sub-ns pulses from a microchip Nd:YAG laser leads to spectrally flat supercontinuum generation with a uniform bell-shaped spatial beam profile extending from the visible to the mid-infrared at 2500 nm. We study the development of the supercontinuum along the multimode fiber by the cut-back method, which permits us to analyze the competition between the Kerr-induced geometric parametric instability and stimulated Raman scattering. We also performed a spectrally resolved temporal analysis of the supercontinuum emission.

Zero focusing via competing nonlinearities in beta-barium-borate crystals

We investigate nonlinear focusing behavior of light beams propagating in beta-barium-borate crystals under mismatched second-harmonic generation. We clearly identify experimentally multiple self-focusing and defocusing regions against the orientation angle and the condition where competing quadratic and cubic nonlinearities perfectly compensate each other (zero-focusing point).

Decreased muscle strength following management of breast cancer

PURPOSE

To assess whether muscle strength, power and endurance at the affected shoulder were reduced in women treated for breast cancer. Secondly, we assessed whether muscle performance was explained by management or other symptoms.

METHODS

Participants were 40 women (mean +/- SD: 56.7 +/- 11.6 yr) who had completed all treatments for breast cancer at least 6 m previously. We measured dynamic concentric strength at one repetition maximum (1RM), endurance at 90% 1RM, and power through a range of 40-100% 1RM for shoulder protractors, extensors and retractors. Strength and endurance, but not power, were measured for shoulder flexors. Additionally, maximal grip strength, passive shoulder range of motion and arm circumference were measured. Self-reported symptoms were recorded using a questionnaire.

RESULTS

Shoulder protractors (p = 0.011), retractors (p = 0.007), and extensors (p = 0.009), but not flexors, were significantly weaker on the affected side compared to the unaffected side. Muscle power and endurance at the shoulder and grip strength were not impaired. Inter-limb differences in muscle strength were not explained by the surgical and medical management of the cancer. Self-reported weakness correlated poorly with our measures of muscle strength.

CONCLUSIONS

Long-term weakness occurs about the shoulder secondary to treatment for breast cancer. Strategies to prevent weakness need to be considered.

Automated telephone follow-up after breast cancer: an acceptability and feasibility pilot study

Traditional clinical follow-up after breast cancer is inefficient at detecting relapse and is poorly suited to detecting and ameliorating psychological problems. There is interest in developing more effective and efficient methods of follow-up. We report a prospective cohort study of the acceptability and feasibility of remote, automated telephone follow-up after breast cancer. Women with a history of breast cancer were approached at their annual follow-up visit. For participants, the follow-up questionnaire was administered on paper at baseline. In place of a clinic visit following year, the women completed the same questionnaire using an automated telephone system. All patients were given mammograms. A semi-structured interview was then conducted to assess the acceptability. The potential impact on clinic usage was assessed. In all, 110 of 121 women (91%) agreed to participate. Seventy-five patients (71%) completed follow-up using the new automated system 1 year later. Seventy-one of the 75 patients found the system easy to use. Forty-nine of the 75 (65.33%) liked the system and were happy to use it as their sole method of follow-up. A further 12% were happy to use it as part of their follow-up. In only 10.66% of participants were concerns raised which led to clinic attendance. Automated questionnaire-based telephone follow-up is acceptable to women and has the potential to reduce attendance at clinic. Further studies to validate this method further are planned.

Changing pattern of the detection of locoregional relapse in breast cancer: the Edinburgh experience

The guidelines for follow-up of breast cancer patients concentrate on the first 3-5 years, with either reduced frequency of visits or discharge after this. They also recommend mammography, but no evidence exists to inform frequency. We analyse treatable relapses in our unit from 1312 patients with early stage breast cancer treated by breast conserving surgery (BCS) and postoperative radiotherapy between 1991 and 1998 to assess appropriateness of the guidelines. A total of 110 treatable relapses were analysed. Treatable relapse developed at 1-1.5% per year throughout follow-up. Forty-eight relapses were in ipsilateral breast, 25 ipsilateral axilla, 35 contralateral breast, 2 both breasts simultaneously. Thirty-seven relapses (33.5%) were symptomatic, 56 (51%) mammographically detected, 15 (13.5%) clinically detected, 2 (2%) diagnosed incidentally. Mammography detected 5.37 relapses per 1000 mammograms. Patients with symptomatic or mammographically detected ipsilateral breast relapse had significantly longer survival from original diagnosis (P=0.0002) and from recurrence (P=0.0014) compared with clinically detected. Treatable relapse occurs at a constant rate for at least 10 years. Clinical examination detects a minority (13.5%). Relapse diagnosed clinically is associated with poorer outcome. Long-term follow-up based on regular mammography is warranted for all patients treated by BCS.

Alternative methods of follow up in breast cancer: a systematic review of the literature

Regular clinical follow up after breast cancer is a common practice. Evidence from retrospective reviews casts doubt on the efficacy of this practice and the various guidelines for follow up show little concordance. Our aim was to investigate what alternative follow-up methods (including reduced frequency of visits) have been subjected to controlled trial and to establish what evidence exists from controlled trials to advise the guidelines. The study involved systematic review of the literature using MEDLINE, Embase, CancerLit, Web of Sciences and EBM reviews as data sources. Methods included reviewing all randomised controlled trials comparing different follow-up frequencies or comparing an alternative method with clinical follow up after breast cancer. All outcome measures addressed in the trials were analysed. Two trials compared frequency of traditional follow up. Five trials assessed alternative methods. All were of inadequate power or duration to establish ideal frequency of clinic visits or safety of alternative follow-up methods. Alternative follow up had no detrimental effect on satisfaction or outcome. Few trials have been conducted, all of which are underpowered to establish safety of reducing or replacing clinic visits. Alternative methods of follow up are acceptable to patients and may be associated with other benefits. Larger trials are required.

ELISA for assessing Toxoplasma gondii antibodies in pigs

The ELISA technique was applied to assess Toxoplasma gondii antibodies in pigs. Among 925 swine examined 36.4 per cent of the animals were seropositive. Serum titres ranged from 100 to 3,200.