306 research outputs found

    A Note on Matter Superenergy Tensors

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    We consider Bel-Robinson-like higher derivative conserved two-index tensors H_\mn in simple matter models, following a recently suggested Maxwell field version. In flat space, we show that they are essentially equivalent to the true stress-tensors. In curved Ricci-flat backgrounds it is possible to redefine H_\mn so as to overcome non-commutativity of covariant derivatives, and maintain conservation, but they become model- and dimension- dependent, and generally lose their simple "BR" form.Comment: 3 page

    Learning effect of humphrey matrix frequency doubling technology perimetry in patients with ocular hypertension

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    Aim: To evaluate the learning effect of Frequency Doubling Technology (FDT) perimetry using the Humphrey Matrix-FDT perimetry (Matrix) 24-2 full-threshold program on patients with 7 ocular hypertension experienced with standard automated perimetry. Methods: Twenty-four patients with Ocular hypertension underwent 5 full-threshold Matrix tests at intervals of 5 2 days. Learning effect was defined as an improvement at results for duration, perimetric indices, foveal sensitivity, Glaucoma Hemifield Test, and the number of points with a P < 5% and < 1% in the total and pattern deviation maps. Eccentricity, hemifield, and quadrant sensitivities were also addressed as Sources of differences in learning effect. Test-retest variability was also calculated for each repetition as the mean of the point-to-point interindividual standard deviations. Results: A learning effect was demonstrated for mean defect (P = 0.031, analysis of variance) and foveal sensitivity (P = 0.009) and it only affected the first test for both parameters. All the other parameters did not show any significant learning effect. The effect was independent From eccentricity and quadrant or hemifield sensitivities. Conclusions: The results of this study demonstrate that the learning effect for Matrix-FDT is mild and it may affect only the first test. Caution is needed in the analysis of the first Matrix-FDT examination and retest may be advisable in the presence of low mean defect

    Titanium-coated polypropylene mesh as innovative bioactive material in conservatives mastectomies and pre-pectoral breast reconstruction

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    Breast reconstruction is rapidly evolving, thanks to the growing acceptance of synthetic meshes as innovative biomaterials. 276 patients undergoing mastectomy (total of 328 mastectomies) were analyzed in a retrospective observational study to evaluate the pre-pectoral immediate breast reconstruction (IBR) using an implant wrapped with Titanium-Coated Polypropylene Mesh (TCPM) vs. patients treated with tissue expander (TE), equally placed pre-pectorally (and wrapped with the same TCPM in 74.3% of the control group’ breasts). 163 patients, of the study group (SG), underwent mastectomy and pre-pectoral IBR with implant wrapped with TCPM, in a one-step surgery, called direct-to-implant technique (DTI), while 113 patients control group (CG) underwent mastectomy and TE. DTI technique has been performed in 192 breasts of the SG while TE procedure in 136 breasts of the CG. The BREAST-Q questionnaire has been provided before the treatment and 2 years later. Baker scale has been used to evaluate capsular contracture. Oncologic, surgical, and aesthetic outcomes along with BREAST-Q scores were analyzed. Additionally, a histologic evaluation was conducted in 11 capsules' samples randomly chosen (6 derived from SG patients and 5 derived from CG). Complications were recorded in 43 cases (29SG-14CG): 8 skin-nipple necrosis (5SG-3CG), 8 wound dehiscence (6SG-2CG), 3 hematomas (1SG-2CG), and 24 infections (8SG-16CG). Grade IV capsular contracture was detected in 9 breasts (1SG-8CG), whereas 254 breasts were grade I (110SG-144CG), 33 (10SG-23CG) grade II, and 32 (4SG-28CG) grade III. Implant wrinkling was detected in 18 cases (10SG-8CG) after 30 months. The local tumor recurrence rate was 5.8%. Three recurrences were on the nipple-areola complex (1.9%). SG patients showed significantly higher rates in the BREAST-Q overall Satisfaction with Outcome (74.1), overall Satisfaction with Breasts (69.1), Psychosocial Well-being (81.9), and Sexual Well-being (63.1), versus CG's patients (p &lt; 0.05). Histological analysis showed a process of normal tissue repair with a complete mesh integration and normal healing. Conservative mastectomies with pre-pectoral IBR assisted by TCPM proved themselves oncologically safe, biologically integrated into native tissues, and highly accepted in terms of quality of life guaranteeing a more natural and aesthetic breast appearance. Core tip: This retrospective observational study provided clinical and histological outcomes of the pre-pectoral IBR using an implant wrapped with TCPM vs. patients treated with TE, equally placed pre-pectorally. The efficacy of IBR using an implant wrapped with TCPM was confirmed by the cosmetic results obtained and by a rate of side effects comparable to TE. All the histological analyses performed confirmed the TCPM mesh complete integration with the physiological aspects of healing: The Collagen 1 and 3 expressions did not differ, between TCPM and NO TCPM samples to confirm a process of healing overlapping to perfect device incorporation and normal healing

    Circadian variations in central corneal thickness and intraocular pressure in patients with glaucoma

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    AIM: To analyse 24 hour variations in intraocular pressure (IOP) and central corneal thickness (CCT) in a group of glaucomatous patients. METHODS: 30 patients with primary open angle glaucoma were hospitalised and underwent circadian evaluations (at 8 pm, midnight, 4 am, 8 am, noon, and 4 pm) of supine and sitting IOP, respectively, measured using a Perkins and a Goldmann tonometer, and CCT measured using an ultrasonic pachymeter (the mean value of three measurements within 5 mum). All patients were treated with timolol 0.5% twice daily and latanoprost 0.005% once daily. RESULTS: Mean supine IOP was 15.3 (SD 3.7) mm Hg (range 10-25), with circadian fluctuations of 7.3 (3.3) mm Hg. Mean sitting IOP was 15.1 (3.9) mm Hg (range 8-26), with circadian fluctuations of 5.4 (3.1) mm Hg. Mean CCT was 534 (39) microm (range 443-637 microm) with circadian fluctuations of 16.5 (6.2) microm (range 6-31 microm). Both the within patient and within time point fluctuations in CCT were statistically significant (p<0.0001, ANOVA). CONCLUSIONS: The authors found considerable fluctuations in 24 hour IOP. The circadian fluctuations in CCT were small and, although statistically significant, did not seem to interfere with the circadian IOP assessment

    The circadian curve of intraocular pressure : can we estimate its characteristics during office hours?

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    PURPOSE: To verify whether office-hour measurements in patients in different body positions can estimate the characteristics of 24-hour intraocular pressure (IOP). METHODS: The 24-hour IOP curves of 29 healthy subjects (10 young adults, 19 elderly) and 30 patients with untreated glaucoma were analyzed. Measurements were taken at 9 AM; 12, 3, 6, and 9 PM; and 12, 3, and 6 AM, both in the supine and sitting (Goldmann tonometer) positions. Peak, mean, and fluctuation of 24-hour IOP curves were compared with office-hour measurements obtained in subjects in the sitting position alone and with combined pressures obtained in the sitting and supine positions (four measurements in each body position from 9 AM to 6 PM). The percentage of subjects with estimates of all IOP parameters within a cutoff of +/-1 (peak and mean) and +/-2 mm Hg (fluctuation) was calculated. RESULTS: Office-hour sitting measurements correctly identified peak, mean, and IOP fluctuation in 10% of the young adults, 32% of the elderly control subjects, and 20% of the patients with glaucoma, whereas the combination of supine and sitting measurements correctly identified them in 30%, 85%, and 46% of cases, respectively. It is noteworthy that office-hour measurements did not characterize any 24-hour parameter in 20% of patients with glaucoma. CONCLUSIONS: Compared with sitting measurements alone, the collection of supine and sitting office-hour measurements may enhance the correct identification of 24-hour IOP characteristics in both control subjects and untreated patients with glaucoma, thus reducing the need for obtaining 24-hour curves to a minority of patients

    Correlation between the progression of optic disc and visual field changes in glaucoma

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    Visual field test and optic disc evaluation are the standard examination techniques used to detect the onset and progression of glaucoma. This explorative study was performed to assess the temporal correlation between visual field and optic disc changes in eyes with ocular hypertension and well-established glaucoma. Eighty-six hypertensive and 16 glaucomatous eyes were followed up for a period of up to 9 years (average 4.4 yrs) using kinetic and computerized static perimetry and optic disc manual morphometry. Perimetric changes were based on a series of strict criteria and optic disc changes were based as a reduction in the baseline rim area/disc area ratio (R/D) measurement exceeding the 99% confidence interval for intraobserver reproducibility (7.7%). Optic disc changes were found prior to visual field changes in four hypertensive eyes, whereas visual field changes were found prior to disc changes in six glaucomatous eyes (p = 0.042). The results of our explorative study suggest that quantitative optic disc analysis may be more sensitive than visual field examination in detecting early glaucomatous changes, whereas visual field examination may be more sensitive than quantitative optic disc analysis in detecting glaucomatous progressions in eyes with well established glaucoma

    An Evaluation of Therapeutic Noninferiority of 0.005% Latanoprost Ophthalmic Solution and Xalatan in Patients With Glaucoma or Ocular Hypertension.

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    PURPOSE: To assess the therapeutic noninferiority of 0.005% latanoprost ophthalmic solution versus Xalatan in the treatment of patients with primary open-angle glaucoma or ocular hypertension. PATIENTS AND METHODS: This was a double-masked, randomized, multicenter study. A total of 184 patients with a diagnosis of unilateral or bilateral primary open-angle glaucoma or ocular hypertension were randomly assigned to either 0.005% latanoprost ophthalmic solution or Xalatan for 12 weeks. The primary end-point was the change in intraocular pressure (IOP) at 12 weeks in the 2 groups. Noninferiority was reached if the 2-sided 95% confidence intervals (CI) for the difference between adjusted treatment means were entirely within the interval from -1.5 to +1.5 mm Hg. RESULTS: The difference between treatments in the change of IOP from baseline to the end of treatment was 0.12 mm Hg (95% CI: -0.47, 0.71) in the intention-to-treat population and 0 mm Hg (95% CI: -0.58, 0.57) in the per protocol population. There was no statistically significant difference between the 2 groups in terms of drug-related adverse events. The most commonly reported drug-related local adverse events were: ocular hyperemia, eyelashes growth, and eye irritation. CONCLUSIONS: This study demonstrates that 0.005% latanoprost ophthalmic solution is noninferior to Xalatan in lowering IOP and is generally well tolerate

    Strategies to estimate the characteristics of 24-hour IOP curves of treated glaucoma patients during office hours

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    Background: It is known that office-hour measurements might not adequately estimate IOP mean, peaks and fluctuations in healthy subjects. The purpose of the present study is to verify whether office-hour measurements in patients in different body positions can estimate the characteristics of 24-hour intraocular pressure (IOP) in treated POAG patients. Methods: The 24-hour IOP curves of 70 eyes of 70 caucasian patients with treated glaucoma were analyzed. Measurements were taken at 9 AM; 12, 3, 6, and 9 PM; and 12, 3, and 6 AM, both in the supine (TonoPen XL) and sitting (Goldmann tonometer) positions. The ability of five strategies to estimate IOP mean, peak and fluctuation was evaluated. Each method was analyzed both with regression of the estimate error on the real value and with "hit or miss" analysis. Results: The least biased estimate of the Peak IOP was obtained using measurements from both supine and sitting positions, also yielding the highest rate of correct predictions (which was significantly different from 3 of the remaining 4 strategies proposed, p < 0.05). Strategies obtained from the combination of supine, sitting and peak measurements resulted to be least biased for the Mean IOP and the IOP Fluctuation estimate, but all strategies were not found significantly different in terms of correct prediction rate (the only significant difference being between the two strategies based on sitting or supine measurements only, with the former being the one with the highest correct prediction rate). Conclusions: The results of this study remark the concept that IOP is a dynamic parameter and that intensive measurement is helpful in determining its characteristics. All office-hour strategies showed a very poor performance of in correctly predicting the considered parameters within the thresholds used in this paper, all scoring a correct prediction rate below 52 %
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