177 research outputs found
Three-Dimensional Radiofrequency Tissue Tightening: A Proposed Mechanism and Applications for Body Contouring
The use of radiofrequency energy to produce collagen matrix contraction is presented. Controlling the depth of energy delivery, the power applied, the target skin temperature, and the duration of application of energy at various soft tissue levels produces soft tissue contraction, which is measurable. This technology allows precise soft tissue modeling at multiple levels to enhance the result achieved over traditional suction-assisted lipectomy as well as other forms of energy such as ultrasonic and laser-generated lipolysis
Recommended from our members
n-3 Fatty Acid Supplementation for the Treatment of Dry Eye Disease.
BackgroundDry eye disease is a common chronic condition that is characterized by ocular discomfort and visual disturbances that decrease quality of life. Many clinicians recommend the use of supplements of n-3 fatty acids (often called omega-3 fatty acids) to relieve symptoms.MethodsIn a multicenter, double-blind clinical trial, we randomly assigned patients with moderate-to-severe dry eye disease to receive a daily oral dose of 3000 mg of fish-derived n-3 eicosapentaenoic and docosahexaenoic acids (active supplement group) or an olive oil placebo (placebo group). The primary outcome was the mean change from baseline in the score on the Ocular Surface Disease Index (OSDI; scores range from 0 to 100, with higher scores indicating greater symptom severity), which was based on the mean of scores obtained at 6 and 12 months. Secondary outcomes included mean changes per eye in the conjunctival staining score (ranging from 0 to 6) and the corneal staining score (ranging from 0 to 15), with higher scores indicating more severe damage to the ocular surface, as well as mean changes in the tear break-up time (seconds between a blink and gaps in the tear film) and the result on Schirmer's test (length of wetting of paper strips placed on the lower eyelid), with lower values indicating more severe signs.ResultsA total of 349 patients were assigned to the active supplement group and 186 to the placebo group; the primary analysis included 329 and 170 patients, respectively. The mean change in the OSDI score was not significantly different between the active supplement group and the placebo group (-13.9 points and -12.5 points, respectively; mean difference in change after imputation of missing data, -1.9 points; 95% confidence interval [CI], -5.0 to 1.1; P=0.21). This result was consistent across prespecified subgroups. There were no significant differences between the active supplement group and the placebo group in mean changes from baseline in the conjunctival staining score (mean difference in change, 0.0 points; 95% CI, -0.2 to 0.1), corneal staining score (0.1 point; 95% CI, -0.2 to 0.4), tear break-up time (0.2 seconds; 95% CI, -0.1 to 0.5), and result on Schirmer's test (0.0 mm; 95% CI, -0.8 to 0.9). At 12 months, the rate of adherence to treatment in the active supplement group was 85.2%, according to the level of n-3 fatty acids in red cells. Rates of adverse events were similar in the two trial groups.ConclusionsAmong patients with dry eye disease, those who were randomly assigned to receive supplements containing 3000 mg of n-3 fatty acids for 12 months did not have significantly better outcomes than those who were assigned to receive placebo. (Funded by the National Eye Institute, National Institutes of Health; DREAM ClinicalTrials.gov number, NCT02128763 .)
Patient-Reported Ocular Disorders and Symptoms in Adults with Moderate-to-Severe Atopic Dermatitis: Screening and Baseline Survey Data from a Clinical Trial
Introduction: Patients with atopic dermatitis
(AD) have a greater risk of conjunctivitis and
other ocular surface disorders than the general
population. We evaluated the burden of ocular
surface disorders and related symptoms prior to
treatment initiation in adults with moderate-tosevere AD.
Methods: Patients were enrolled in a randomized, placebo-controlled, double-blinded,
phase 3 trial of dupilumab administered with
concomitant topical corticosteroids. At the
beginning of the screening period, all enrolled
patients completed a survey of ocular disorder
diagnoses received in the past year; at baseline,
patients completed a survey of frequency and
severity of ocular symptoms (discomfort, itching, redness, and tearing) experienced in the
past month.
Results: A total of 712 of 740 patients enrolled
in the trial provided responses to the survey. At
screening, 286 of 740 patients (38.6%) reported
having at least one ocular disorder in the past
year. At baseline, 499 of 712 respondents
(70.1%) reported having at least one symptom
within the past month. Of these patients, 4.4%,
6.0%, 5.5%, and 4.4%, respectively, reported
h
Fluorophotometry as a diagnostic tool for the evaluation of dry eye disease
BACKGROUND: Dry eye disease is a common debilitating ocular disease. Current diagnostic tests used in dry eye disease are often neither sensitive nor reproducible, making it difficult to accurately diagnose and determine end points for clinical trials, or evaluate the usefulness of different medications in the treatment of dry eye disease. The recently developed fluorophotometer can objectively detect changes in the corneal epithelium by quantitatively measuring its barrier function or permeability. The purpose of the study is to investigate the use of corneal fluorescein penetration measured by the fluorophotometer as a diagnostic tool in the evaluation of dry eye patients. METHODS: Dry eye patients (16 eyes), who presented with a chief complaint of ocular irritation corresponding with dry eye, low Schirmer's one test (<10 mm after 5 minutes) and corneal fluorescein staining score of more than two, were included in the study. Normal subjects (16 eyes), who came for refraction error evaluation, served as controls. Institutional Review Board (IRB) approved consent was obtained before enrolling the subjects in the study and all questions were answered while explaining the risks, benefits and alternatives. All Fluorophotometry of the central corneal epithelium was done utilizing the Fluorotron Master (TradeMark). Each eye had a baseline fluorescein scan performed, after which 50 l of 1% sodium fluorescein dye was instilled. Three minutes later, the fluorescein was washed with 50 ml of normal saline. Fluorescein scans were then started immediately after washing and were recorded at 10, 20, 40, and 60 minutes thereafter. The corneal peak values of fluorescein concentration were recorded within the central cornea in both dry eyes and in controls. RESULTS: Ten minutes after fluorescein installition, patients with dry eye disease averaged a five-fold increase in corneal tissue fluorescein concentration (mean = 375.26 ± 202.67 ng/ml) compared with that of normal subjects (mean = 128.19 ± 85.84 ng/ml). Sixty minutes after dye installation, patients with dry eye disease still revealed higher corneal tissue fluorescein concentration (mean = 112.87 ± 52.83 ng/ml) compared with that of controls (mean = 40.64 ± 7.96 ng/ml), averaging a three-fold increase. CONCLUSION: Patients with dry eye disease demonstrated an increased corneal permeability and a slower rate of elimination to topically administered fluorescein when measured by the fluorophotometer. This suggests that fluorophotometry may serve as a valuable quantitative and objective tool for the diagnosis of dry eye disease, and in following patients' response to new treatment modalities. Fluorophotometry may serve as an objective non-invasive tool for end-point analysis in clinical trials of new treatments for dry eye disease
Intensity modulated radiotherapy for high risk prostate cancer based on sentinel node SPECT imaging for target volume definition
BACKGROUND: The RTOG 94-13 trial has provided evidence that patients with high risk prostate cancer benefit from an additional radiotherapy to the pelvic nodes combined with concomitant hormonal ablation. Since lymphatic drainage of the prostate is highly variable, the optimal target volume definition for the pelvic lymph nodes is problematic. To overcome this limitation, we tested the feasibility of an intensity modulated radiation therapy (IMRT) protocol, taking under consideration the individual pelvic sentinel node drainage pattern by SPECT functional imaging. METHODS: Patients with high risk prostate cancer were included. Sentinel nodes (SN) were localised 1.5–3 hours after injection of 250 MBq (99m)Tc-Nanocoll using a double-headed gamma camera with an integrated X-Ray device. All sentinel node localisations were included into the pelvic clinical target volume (CTV). Dose prescriptions were 50.4 Gy (5 × 1.8 Gy / week) to the pelvis and 70.0 Gy (5 × 2.0 Gy / week) to the prostate including the base of seminal vesicles or whole seminal vesicles. Patients were treated with IMRT. Furthermore a theoretical comparison between IMRT and a three-dimensional conformal technique was performed. RESULTS: Since 08/2003 6 patients were treated with this protocol. All patients had detectable sentinel lymph nodes (total 29). 4 of 6 patients showed sentinel node localisations (total 10), that would not have been treated adequately with CT-based planning ('geographical miss') only. The most common localisation for a probable geographical miss was the perirectal area. The comparison between dose-volume-histograms of IMRT- and conventional CT-planning demonstrated clear superiority of IMRT when all sentinel lymph nodes were included. IMRT allowed a significantly better sparing of normal tissue and reduced volumes of small bowel, large bowel and rectum irradiated with critical doses. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG) occurred. CONCLUSION: IMRT based on sentinel lymph node identification is feasible and reduces the probability of a geographical miss. Furthermore, IMRT allows a pronounced sparing of normal tissue irradiation. Thus, the chosen approach will help to increase the curative potential of radiotherapy in high risk prostate cancer patients
A study of family mediation during divorce in the Pakistani Muslim community in Bradford. Some observations on the implications for the theory and practice of conflict resolution.
Conflict resolution theory and practice have been increasingly criticised for ignoring the
centrality of culture in their attempts to find theories and models that are applicable
universally, not only across cultures but also across levels of society. Mediation is one
form of conflict resolution, which has come to occupy a central position in the resolution of
disputes both at international and local levels. At the level of family disputes, family
mediation has failed to engage users from different ethnic groups in England and Wales.
This thesis explores the hypothesis that culture and, in particular, culturally defined
concepts of gender are the important factors determining the success or failure of mediation
in divorce disputes.J. A. Clark Charitable Trus
Equal access, (Un)equal uptake: a longitudinal study of cataract surgery uptake in older people in England
Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments
[EN] Radio-frequency thermokeratoplasty (RF-TKP) is a technique used to reshape the cornea curvature by means of thermal lesions using radio-frequency currents. This curvature change allows refractive disorders such as hyperopia to be corrected. A new electrode with ring geometry is proposed for RF-TKP. It was designed to create a single thermal lesion with a full-circle shape. Finite element models were developed, and the temperature distributions in the cornea were analysed for different ring electrode characteristics. The computer results indicated that the maximum temperature in the cornea was located in the vicinity of the ring electrode outer perimeter, and that the lesions had a semi-torus shape. The results also indicated that the electrode thickness, electrode radius and electrode thermal conductivity had a significant influence on the temperature distributions. In addition, in vitro experiments were performed on rabbit eyes. At 5 IN power the lesions were fully circular. Some lesions showed non-uniform characteristics along their circular path. Lesion depth depended on heating duration (60% of corneal thickness for 20s, and 30% for 10s). The results suggest that the critical shrinkage temperature (55-63degreesC) was reached at the central stroma and along the entire circular path in all the cases.Berjano, E.; Saiz RodrÃguez, FJ.; Alió, J.; Ferrero, JM. (2003). Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments. Medical & Biological Engineering & Computing. 41(6):630-639. https://doi.org/10.1007/BF02349970S630639416Alió, J. L., Ismail, M. M., Artola, A., andPérez-Santonja, J. J. (1997a): ‘Correction of hyperopia induced by photorefractive keratectomy using non-contact Ho: YAG laser thermal keratoplasty’,J. Refract. Surg.,13, pp. 13–16Alió, J. L., Ismail, M. M., andSanchez, J. L. (1997b): ‘Correction of hyperopia with non-contact Ho: YAG laser thermal keratoplasty’,J. Refract. Surg.,13, pp. 17–22Alió, J. L., andPérez-Santonja, J. J. (1999): ‘Correction of hyperopia by laser thermokeratoplasty (LTK)’ inPallikaris, I., andAgarwal, S. (Eds): ‘Refractive Surgery’ (Jaypee Brothers Medical Publishers Ltd, New Delhi, 1999), pp. 583–591Alió, J. L., andPérez-Santonja, J. J. (2002): ‘Correction of hyperopia by laser thermokeratoplasty (LTK)’ inAgarwal, S., Agarwal, A., Apple, D. J., Buratto, L., Alió, J. L., Pandey, S. K., andAgarwal, A. (Eds): ‘Textbook of ophthalmology’ (Lippincott Williams & Wilkins, Philadelphia, 2002), pp. 1331–1337Ayala, M. J., Alió, J. L., Ismail, M. M., andSánchez-Castro, J. M. (2000): ‘Experimental corneal histological study after thermokeratoplasty with holmium laser’,Arch. Soc. Esp. Oftalmol.,75, pp. 619–626Asbell, P. A., Maloney, R. K., Davidorf, J., Hersh, P., McDonald, M., Manche, E., andConductive Keratoplasty Study Group (2001): ‘Conductive keratoplasty for the correction of hyperopia’,Tr. Am. Ophtalmol. Soc.,99, pp. 79–87Avitall, B., Mughal, K., Hare, J., Helms, R., andKrum, D. (1997): ‘The effects of electrode-tissue contact on radiofrequency lesion generation’PACE,20, pp. 2899–2910Avitall, B., Helms, R. W., Koblish, J. B., Sieben, W., Kotov, A. V., andGupta, G. N. (1999): ‘The creation of linear contiguous lesions in the atria with an expandable loop catheter’,J. Am. Coll. Cardiol.,33, pp. 972–984Berjano, E. J., Saiz, J., andFerrero, J. M. (2002): ‘Radio-frequency heating of the cornea: Theoretical model andin vitro experiments’,IEEE Trans. Biomed. Eng.,49, pp. 196–205Brickmann, R., Kampmeier, J., Grotehusmann, U., Vogel, A., Koop, N., Asiyo-Vogel, M., Kamm, K., andBirngruber, R. (1996): ‘Corneal collagen denaturation in laserthermokeratoplasty’,SPIE Proc.,2681, pp. 56–63Choi, B., Kim, J., Welch, A. J., andPearce, J. A. (2002): ‘Dynamic impedance measurements during radio-frequency heating of cornea’,IEEE Trans. Biomed. Eng.,49, pp. 1610–1616Curley, M. G., andHamilton, P. S. (1997): ‘Creation of large thermal lesions in liver using saline-enhanced RF ablation’. Proc. 19th Ann. Int. Conf. IEEE Eng. Med. Biol. Soc., Chicago, pp. 2516–2519Doss, J. D., andAlbillar, J. I. (1980): ‘A technique for the selective heating of corneal stroma’,Contact Intraocular Lens Med.,6, pp. 13–17Doss, J. D. (1982): ‘Calculation of electric fields in conductive media’,Med. Phys.,9(4), pp. 566–573Gruenberg, P., Manning, W., Miller, D. andOlson, W. (1981): ‘Increase in rabbit corneal curvature by heated ring application’,Ann. Ophthalmol.,13, pp. 67–70Hata, C., andRaymond Chia, W.-K. (2001): ‘Catheter for circular tissue ablation and methods thereof’. US Patent 2001/0044625 A1Jain, M. K., andWolf, P. D. (1998): ‘Effect of electrode contact on lesion growth during temperature controlled radiofrequency ablation’, Proc. 20th Ann. Int. Conf. IEEE Eng. Med. Biol. Soc. Hong Kong (IEEE, Piscataway NJ) pp. 245–247Jain, M. K., andWolf, P. D. (1999): ‘Temperature controlled and constant power radiofrequency ablation: what affects lesion growth?’,IEEE Trans. Biomed. Eng.,46, pp. 1405–1412Krasteva, V. Tz., andPapazov, S. P. (2002): ‘Estimation of current density distribution under electrodes for external defibrillation’,Biomed. Eng. OnLine,1, 7Labonté, S. (1992): ‘A theoretical study of radio-frequency ablation of the myocardium’,PhD dissertation, Department of Electrical Engineering, University of Ottawa, CanadaLabonté, S. (1994): ‘Numerical model for radio-frequency ablation of the endocardium and its experimental validation’,IEEE Trans. Biomed. Eng.,41, pp. 108–115Mannis, M. J., Segal, W. A., andDarlington, J. K. (2001): ‘Making sense of refractive surgery in 2001: Why, when, for whom, and by whom?’,Mayo Clin. Proc.,76, pp. 823–829McCally, R. L., Bargeron, R. A., andGreen, W. R. (1983): ‘Stromal damage in rabbit corneas exposed to CO2 laser radiation’,Exp. Eye Res.,37, pp. 543–550McDonald, M. B., Hersh, P. S., Manche, E. E., Maloney, R. K., Davidorf, J., andSabry, M. (2002): ‘Conductive keratoplasty for the correction of low to moderate hyperopia: U.S. clinical trial 1-year results on 355 eyes’,Ophthalmol.,109, pp. 1978–1989McRury, I. D., Mitchell, M. A., Panescu, D. andHaines, D. E. (1997): ‘Non-uniform heating during radiofrequency ablation with long electrodes: monitoring the edge effect’,Circ.,96, pp. 4057–4064Méndez-g, A., andMéndez-Noble, A. (1997): ‘Conductive keratoplasty of the correction of hyperopia’ inSher, N. A. (Ed.) ‘Surgery for hyperopia and presbyopia’ (Williams & Wilkins, Baltimore, 1997), pp. 163–171Miller, D., andManning, W.J. (1978): ‘Alterations in curvature of bovine cornea using heated rings’,Invest. Ophthalmol., p. 297Mirotznik, M. S., andSchwartzman, D. (1996): ‘Nonuniform heating patterns of commercial electrodes for radiofrequency catheter ablation’,J. Cardiovasc. Electrophysiol.,7, pp. 1058–1062Nakagawa, H., Yamanashi, W. S., Pitha, J. V., Arruda, M., Wang, X., Ohtomo, K., Beckman, K. J., McClelland, J. H., Lazzara, R., andJackman, W. M. (1995): ‘Comparison ofin vivo tissue temperature profile and lesion geometry for radiofrequency ablation with a saline-irrigated electrode versus temperature control in a canine thigh muscle preparation’,Circ.,91, pp. 2264–2273Panescu, D., Whayne, J. G., Fleischman, S. D., Mirotznik, M. S., Swanson, D. K., andWebster, J. G. (1995): ‘Three-dimensional finite element analysis of current density and temperature distributions during radio-frequency ablation’,IEEE Trans. Biomed. Eng.,42, pp. 879–890Plonsey, R., andHeppner, D. B. (1967): ‘Considerations of quasistationarity in electrophysiological systems’,Bull. Math. Biophys.,29, pp. 657–664Rowsey, J. J. (1987): ‘Electrosurgical keratoplasty: Update and retraction’,Invest. Ophthalmol. Vis. Sci.,28, p. 224Rutzen, A. R., Roberts, C. W., Driller, J., Gomez, D., Lucas, B. C., Lizzi, F. L., andColeman, D. J. (1990): ‘Production of corneal lesions using high-intensity focused ultrasound’,Cornea,9, pp. 324–330Schwan, H. P., andFoster, K. R. (1980): ‘RF-fields interactions with biological systems: electrical properties and biophysical mechanism’,Proc. IEEE,68, pp. 104–113Seiler, T., Matallana, M., andBende, T. (1990): ‘Laser thermokeratoplasty by means of a pulsed Holmium:YAG Laser for the hyperopic correction’,Refrac. Corneal Surg.,6, pp. 335–339Silvestrini, T. A. (1998): ‘Electrosurgical procedure for the treatment of the cornea’. US Patent 5,766,171Simmons, W. N., Mackey, S., He, D. S. andMarcus, F. L. (1996): ‘Comparison of gold versus platinum electrodes on myocardial lesion size using radiofrequency energy’,PACE,19, pp. 398–402Stringer, H., andParr, J. (1964): ‘Shrinkage temperature of eye collagen’,Nature,204, p. 1307Trembly, B. S., andKeates, R. H. (1991): ‘Combined microwave heating and surface cooling of the cornea’,IEEE Trans. Biomed. Eng.,38, pp. 85–91Trembly, B. S., Hashizume, N., Moodie, K. L., Cohen, K. L., Tripoli, N. K., andHoopes, P. J. (2001): ‘Microwave thermal keratoplasty for myopia: keratoscopic evaluation in porcine eyes’,J. Refract. Surg.,17, pp. 682–688Tungjitkusolmun, S., Woo, E. J., Cao, H., Tsai, J. Z., Vorperian, V. R., andWebster, J. G. (2000): ‘Thermal-electrical finite element modelling for radio frequency cardiac ablation: effects of changes in myocardial properties’,Med. Biol. Eng. Comput.,38, pp. 562–568Wiley, J. D., andWebster, J. G. (1982): ‘Analysis and control of the current distribution under circular dispersive electrodes’,IEEE Trans. Biomed. Eng,29, pp. 381–38
- …