Effect of Femtosecond Laser Energy Level on Corneal Stromal Cell Death and Inflammation

PURPOSE: To analyze the effects of variations in femtosecond laser energy level on corneal stromal cell death. and inflammatory cell influx following flap creation in a rabbit model. METHODS: Eighteen rabbits were stratified in three different groups according to level of energy applied for flap creation (six animals per group). Three different energy levels were chosen for both the lamellar and side cut; 2.7 mu J (high energy), 1.6 mu J (intermediate energy), and 0.5 mu J (low energy) with a 60 kHz, model II, femtosecond laser (IntraLase). The opposite eye of each rabbit served as a control. At the 24-hour time point after surgery, all rabbits were euthanized and the comeoscleral rims were analyzed for the levels of cell death and inflammatory cell influx with the terminal uridine deoxynucleotidyl transferase dUTP-nick end labeling (TUNEL) assay and immunocytochemistry for monocyte marker CD11b, respectively. RESULTS: The high energy group (31.9 +/- 7.1 [standard error of mean (SEM) 2.9]) had significantly more TUNEL positive cells in the central flap compared to the intermediate (22.2 +/- 1.9 [SEM 0.8], P=.004), low (17.9 +/- 4.0 [SEM 1.6], P <= .001), and control eye (0.06 +/- 0.02 [SEM 0.009], P <= .001) groups. The intermediate and low energy groups also had significantly more TUNEL positive cells than the control groups (P <= .001). The difference between the intermediate and low energy levels was not significant (P=.56). The mean for CD11b-positive cells/400x field at the flap edge was 26.1 +/- 29.3 (SEM 11.9), 5.8 +/- 4.1 (SEM 1.6), 1.6 +/- 4.1 (SEM 1.6), and 0.005 +/- 0.01 (SEM 0.005) for high energy, intermediate energy, low energy, and control groups, respectively. Only the intermediate energy group showed statistically more inflammatory cells than control eyes (P = .015), most likely due to variability between eyes. CONCLUSIONS: Higher energy levels trigger greater cell death when the femtosecond laser is used to create corneal flaps: Greater corneal inflammatory cell infiltration is observed with higher femtosecond laser energy levels. [J Refract Surg. 2009;25:869-874.] doi:10.3928/1081597X-20090917-08

A study of actinic cheilitis treatment by two low-morbidity CO(2) laser vaporization one-pass protocols

Therapeutic approaches to chronic actinic cheilitis focus on the removal or destruction of diseased epithelium. The CO(2) laser has become an important therapeutic alternative, achieving clinical resolution in around 90% of patients. Although many laser physical parameters have been reported, some are known for their low potential for scar induction without compromising the success of the results. The aim of this clinicohistological study was to compare the therapeutic responses to two low-morbidity protocols involving a single laser pass. A total of 40 patients with chronic multicentric and microscopically proven disease were randomly submitted to two conservative CO(2) laser protocols using a bilateral comparative model. The degree of histological atypia of the epithelium was determined in 26 patients both pre- and postoperatively for both protocols. Other histological phenomena were assessed in addition to this central analysis parameter. Clinical recurrence occurred in 12.5% of patients for each protocol, together with a significant reduction in the degree of epithelial atypia (p < 0.001), which was occasionally complete. However, no difference was found between the protocols (p > 0.05). Using these morphological parameters it was not possible to determine whether postoperative epithelial atypias in part of the sample were reactive or residual in nature. A few patients may show minor postoperative lesions. Due to their potential to achieve clinical and importantly microscopic resolution, the studied protocols may be used for mild through moderate dysplastic epithelium and clinically diffuse disease.

Percutaneous Laser Ablation of Sacrococcygeal Teratoma in a Hydropic Fetus with Severe Heart Failure - Too Late for a Surgical Procedure?

Sacrococcygeal teratoma (SCT) is the commonest solid fetal tumor. Perinatal prognosis is usually favorable, but sometimes it can be complicated by fetal hydrops being responsible for high risk of mortality. Fetal therapy in such cases has so far not been established. We report a case with a giant solid SCT associated with fetal hydrops and severe heart failure. 2D- and 3D-Doppler ultrasonography revealed great vessels originated from the medial sacral artery. Percutaneous laser ablation of these vessels was performed at 24 weeks of gestation. During the procedure, severe anemia was also diagnosed (hemoglobin 4.3 g/dl). Two days later, the fetus died and pathological examination revealed local tumor necrosis and blood hemorrhage inside the mass. We suggest that in such cases, fetal surgery may not be enough, being too late, and perhaps fetal clinical therapy for anemia and heart failure could be the best option at a gestational age of less than 28 weeks. Copyright (C) 2009 S. Karger AG, Basel

Aerobic exercise training improves the role of high-density lipoprotein antioxidant and reduces plasma lipid peroxidation in type 2 diabetes mellitus

In this study, we analyzed the effect of aerobic exercise training (AET) and of a single bout of exercise on plasma oxidative stress and on antioxidant defenses in type 2 diabetes mellitus (DM) and in healthy control subjects (C). DM and C did not differ regarding triglycerides, high-density lipoprotein cholesterol (HDL-c), insulin, and HOMA index at baseline and after AET. To measure the lag time for low-density lipoprotein (LDL) oxidation (LAG) and the maximal rate of conjugated diene formation (MCD), participants` plasma HDL(2) and HDL(3) were incubated with LDL from pooled healthy donors` plasma. In the presence of HDL(3), both LAG and MCD were similar in C and DM, but only in DM did AET improve LAG and reduce MCD. In the presence of HDL(2), the lower baseline LAG in DM equaled C after AET. MCD was unchanged in DM after AET, but was lower than C only after AET. Furthermore, after AET plasma thiobarbituric acid-reactive substances were reduced only in DM subjects. Despite not modifying the total plasma antioxidant status and serum paraoxonase-1 activity in both groups, AET lowered the plasma lipid peroxides, corrected the HDL(2), and improved the HDL(3) antioxidant efficiency in DM independent of the changes in blood glucose, insulin, and plasma HDL concentration and composition.

Scanning laser polarimetry with enhanced corneal compensation for detection of axonal loss in band atrophy of the optic nerve

PURPOSE: To compare the abilities of scanning laser polarimetry (SLP) with enhanced corneal compensation (ECC) and variable corneal compensation (VCC) modes for detection of retinal nerve fiber layer (RNFL) loss in eyes with band atrophy (BA) of the optic nerve. DESIGN. Cross-sectional study. METHODS: Thirty-seven eyes from 37 patients with BA and temporal visual field defect from chiasmal compression and 40 eyes from 40 healthy subjects were studied. Subjects underwent standard automated perimetry and RNFL measurements using an SLP device equipped with VCC and ECC. Receiver operating characteristic (ROC) curves were calculated for each parameter. Pearson correlation coefficients were obtained to evaluate the relationship between RNFL thickness parameters and severity of visual field loss, as assessed by the temporal mean defect. RESULTS: All RNFL thickness parameters were significantly lower in eyes with BA compared with normal eyes with both compensation modes. However, no statistically significant differences were observed in the areas under the ROC curves for the different parameters between GDx VCC and ECC (Carl Zeiss Meditec, Inc, Dublin, California, USA). Structure-function relationships also were similar for both compensation modes. CONCLUSIONS: No significant differences were found between the diagnostic accuracy of GDx ECC and that of VCC for detection of BA of the optic nerve. The use of GDx ECC does not seem to provide a better evaluation of RNFL loss on the temporal and nasal sectors of the peripapillary retina in subjects with BA of the optic nerve.

Nonsurgical Periodontal Therapy Combined with Laser and Photodynamic Therapies for Periodontal Disease in Immunosuppressed Rats

Background. Periodontal disease is often associated with systemic diseases and is characterized by destruction of the tissues supporting the teeth. Patients using immunosuppressive drugs such as tacrolimus are among those who suffer from tissue destruction. Objective. We sought to evaluate the effects of laser and photodynamic therapies (PDT; nonsurgical) as an adjunct to scaling and rootplaning (SRP) in the treatment of corona-induced periodontitis in rats immunosuppressed with tacrolimus (Prograf). Materials and Methods. The animals were divided into 5 groups. Each groups had 6 rats. Group I, the control group, received only saline solution throughout the study period of 42 days and did not receive periodontal treatment; group II received saline solution and SRP; group III received tacrolimus (1 mg/kg per day) and was treated with SRP; group IV animals were treated identically to group III and then administered laser treatment; and in group V, the animals were treated identically to group III and then administered PDT. Results. Statistical analysis indicated decreased bone loss with the progression of time (P = .035). There was no difference between the bone loss associated with the types of treatment administered to groups I, II, and III (P > .9) or groups IV and V (P > .6). The analysis also indicated that immunosuppression was not a bone loss-determining factor. Conclusion. Laser and PDT therapies were effective as an adjunctive treatment to SRP in reducing bone loss caused by experimental periodontitis induced in animals being treated systemically with tacrolimus.

Role of promoter polymorphisms in the plasma glutathione peroxidase (GPx-3) gene as a risk factor for cerebral venous thrombosis

Background and Purpose-Plasma glutathione peroxidase (GPx-3) is a major antioxidant enzyme in plasma and the extracellular space that scavenges reactive oxygen species produced during normal metabolism or after oxidative insult. A deficiency of this enzyme increases extracellular oxidant stress, promotes platelet activation, and may promote oxidative posttranslational modification of fibrinogen. We recently identified a haplotype (H-2) in the GPx-3 gene promoter that increases the risk of arterial ischemic stroke among children and young adults. Methods-The aim of this study is to identify possible relationships between promoter haplotypes in the GPx-3 gene and cerebral venous thrombosis (CVT). We studied the GPx-3 gene promoter from 23 patients with CVT and 123 young controls (18 to 45 years) by single-stranded conformational polymorphism and sequencing analysis. Results-Over half of CVT patients (52.1%) were heterozygous (H1H2) or homozygous (H2H2) carriers of the H-2 haplotype compared with 12.2% of controls, yielding a more than 10-fold independent increase in the risk of CVT (OR=10.7; 95% CI, 2.70 to 42.36; P<0.0001). Among women, the interaction of the H2 haplotype with hormonal risk factors increased the OR of CVT to almost 70 (P<0.0001). Conclusions-These findings show that a novel GPx-3 promoter haplotype is a strong, independent risk factor for CVT. As we have previously shown that this haplotype is associated with a reduction in transcriptional activity, which compromises antioxidant activity and antithrombotic benefits of the enzyme, these results suggest that a deficiency of GPx-3 leads to a cerebral venous thrombophilic state.

Effects of low level laser therapy (808 nm) on physical strength training in humans

Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8 +/- 2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P = 0.033) and in the CG subjects (0.27%, P < 0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P = 0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.

Comparative effects of wavelengths of low-power laser in regeneration of sciatic nerve in rats following crushing lesion

Peripheral nerves are structures that, when damaged, can result in significant motor and sensory disabilities. Several studies have used therapeutic resources with the aim of promoting early nerve regeneration, such as the use of low-power laser. However, this laser therapy does not represent a consensus regarding the methodology, thus yielding controversial conclusions. The objective of our study was to investigate, by functional evaluation, the comparative effects of low-power laser (660 nm and 830 nm) on sciatic nerve regeneration following crushing injuries. Twenty-seven Wistar rats subjected to sciatic nerve injury were divided into three groups: group sham, consisting of rats undergoing simulated irradiation; a group consisting of rats subjected to gallium-aluminum-arsenide (GaAlAs) laser at 660 nm (10 J/cm(2), 30 mW and 0.06 cm(2) beam), and another one consisting of rats subjected to GaAlAs laser at 830 nm (10 J/cm(2), 30 mW and 0.116 cm(2)). Laser was applied to the lesion for 21 days. A sciatic functional index (SFI) was used for functional evaluation prior to surgery and on days 7, 14, and 21 after surgery. Differences in SFI were found between group 660 nm and the other ones at the 14th day. One can observe that laser application at 660 nm with the parameters and methods utilised was effective in promoting early functional recovery, as indicated by the SFI, over the period evaluated.

LOCAL LOW POWER LASER IRRADIATION ACCELERATES THE REGENERATION OF THE FIBULAR NERVE IN RATS

Objective: To study the influence of low power GaAsAl laser irradiation on the regeneration of a peripheral nerve, following a controlled crush injury. Material and methods: The right common fibular nerve of 30 Wistar rats was submitted to a crush injury with an adjustable load forceps (5 000 g, 10 minutes of application). The animals were divided into three groups (n=10), according to the postoperative procedure (no irradiation; sham irradiation; effective irradiation). Laser irradiation (830 nm wave-length; 100 mW emission power; continuous mode; 140 J/cm(2)) was started on the first postoperative day and continued over 21 consecutive days. Body mass, time spent on the walking track and functional peroneal index (PFI) were analyzed based on the hind footprints, both preoperatively and on the 21st postoperative day. Results: Walking time and PFI significantly improved in the group that received effective laser irradiation, despite the significant gain in body mass between the pre- and post-operative periods. Conclusion: Low Power GaAsAl laser irradiation, with the parameters used in our study, accelerated and improved fibular nerve regeneration in rats.

INFLUENCE OF LASER RADIATION IN NERVE REGENERATION IN DIFFERENT TREATMENT SITES

Objective: This study seeks to determine, through functional gait assessment in different irradiation sites, the influence of a low-intensity GaAsAl laser beam on an injury caused by crushing the peroneal nerve in rats. Methods: 53 rats were used, which were divided into six groups: normal, injured and untreated, injured and treated using placebo, injured and treated in the bone marrow, injured and treated in the nerve, and injured and treated in both (nerve and bone marrow). The peroneal nerve was crushed using a pair of tweezers, and subsequently treated with laser for 28 consecutive days. The functional gait evaluation analyzed the footprints, which were recorded with a video camera on an acrylic bridge in the preoperative period, and on postoperative days 14, 21 and 28, and assessed using PFI formula software. Results: In the functional gait evaluation, significant differences were found only on postoperative day 14. Conclusion: Based on the functional gait evaluation, low-intensity GaAs AI irradiation was able to accelerate and reinforce the process of peripheral nerve regeneration in rats on postoperative day 14, both in the bone marrow- and in the nerve-treated groups.

Altered plasma response to zinc and iron tolerance test after Roux-en-Y gastric bypass

Background: The duodenum and proximal jejunum are excluded after Roux-en-Y gastric bypass but these intestinal sites are where iron and zinc are most absorbed. Therefore, they are among the nutrients whose digestive and absorptive process can be impaired after surgery. The aim of the present study was to investigate the iron and zinc plasma response to a tolerance test before and after bariatric surgery. The study was performed at Sao Paulo University School of Medicine of Ribeirao Preto, Brazil. Methods: In a longitudinal paired study, 9 morbidly obese women (body mass index >= 40 kg/m(2)) underwent an iron and zinc tolerance test before and 3 months after surgery. The iron and zinc levels were determined at 0, 1, 2, 3, and 4 hours after a physiologic unique oral dose. The mineral concentrations in die plasma and 24-hour urine sample were assayed using an atomic absorption spectrophotometer. The anthropometric measurements and 3-day food record were also evaluated. A linear mixed model was used to compare the plasma concentration versus interval after the oral dose, before and after surgery. Results: The pre- and postoperative test results revealed a significantly lower plasma zinc response (P <.01) and a delayed response to iron intake after surgery. The total plasma iron concentration area, during the 4 hours, was not different after surgery (P >.05). The 24-hour urinary iron and zinc excretion did not differ between the pre- and postoperative phases. Conclusion: The present data showed a compromised response to the zinc tolerance test after gastric bypass surgery, suggesting an impaired absorption of zinc. More attention must be devoted to zinc nutritional status after surgery. (Surg Obes Relat Dis 2011;7:309-314.) (C) 2011 American Society for Metabolic and Bariatric Surgery. All rights reserved.

Plasma nitrate/nitrite (NOx) is not a useful biomarker to predict inherent cardiopulmonary bypass inflammatory response

Background and Aim: There were strong evidences that nitric oxide has capital importance in the progressive vasodilatation associated with varied circulatory shock forms, including systemic inflammatory response syndrome (SIRS), in patients undergoing cardiac surgeries for cardiopulmonary bypass (CPB). If CPB procedures, per se, are the inciting stimulus for inflammation, plasma nitrate/nitrite (NOx) excretion would be expected to be higher in these patients rather than in patients operated without CPB. In consequence, we hypothesized that increased levels of NOx would be predictive for vasoplegic syndrome. Methods: Thirty patients were assigned to three groups: Group 1-coronary artery bypass graft (CABG) roller pump CPB; Group 2-CABG centrifugal vortex pump CPB; and Group 3-heart valve surgery roller pump CPB. Sampling of venous blood for chemiluminescence plasma NOx dosage was achieved at the following time points: (1) before anesthesia induction; (2) after anesthesia induction; (3) before heparin infusion; (4) after heparin infusion; (5) CPB-30 minutes; (6) CPB-60 minutes; (7) before protamine infusion; (8) after protamine infusion; and (9) on return to the recovery area. Results: There were no intergroup differences regarding age and anesthetic regimen, and the number of arteries grafted was not different between the CABG groups. There were no NOx statistic differences, neither among the three groups of patients or among the surgery time. In addition, there was no correlation among NOx, lactate, and hemoglobin. Conclusions: Considering the inflammatory process intrinsic to CPB, this study reinforces the idea that plasma NOx is not useful as a biomarker of inflammatory response onset, which may or may not lead to SIRS and/or vasoplegic syndrome.

Enantioselective Determination of Mexiletine and Its Metabolites p-Hydroxymexiletine and Hydroxymethylmexiletine in Rat Plasma by Normal-Phase Liquid Chromatography-Tandem Mass Spectrometry: Application to Pharmacokinetics

Mexiletine (MEX), hydroxymethylmexiletine (HMM) and P-hydroxy-mexiletine (PHM) were analyzed in rat plasma by LC-MS/MS. The plasma samples were prepared by liquid-liquid extraction using methyl-tert-butyl ether as extracting solvent. MEX, HMM, and PHM enantiomers were resolved on a Chiralpak (R) AD column. Validation of the method showed a relative standard deviation (precision) and relative errors (accuracy) of less than 15% for all analytes studied. Quantification limits were 0.5 ng ml(-1) for the MEX and 0.2 ng ml(-1) for the HMM and PHM enantiomers. The validated method was successfully applied to quantify the enantiomers of MEX and its metabolites in plasma samples of rats (n = 6) treated with a single oral dose of racemic MEX. Chirality 21:648-656, 2009. (C) 2008 Wiley-Liss, Inc.

Effects of a Low-Protein Diet on Plasma Amino Acid and Homocysteine Levels and Oxidative Status in Rats

Background/Aims: Transmethylation reactions and antioxidant metabolism are linked by transsulfuration, where homocysteine (Hcy) is converted to cysteine and reduced glutathione (GSH). Low protein intake can modulate the balance of this metabolic reaction. The aim of the present investigation was to study the effect of a low-protein diet on Hcy metabolism by monitoring levels of the amino acids involved in these pathways, and relating these levels to GSH levels and lipid peroxidation in rats. Methods: Sixteen rats were divided into 2 groups: control (C; standard AIN-93 diet, 20% protein) and low-protein diet (LPD; 8% protein diet). Rats in both groups were placed on the diets for 28 days. Results: A significant reduction (p < 0.05) in plasma Hcy concentration was found in LPD rats (0.16 +/- 0.04 mu mol/mg protein) versus C rats (0.25 +/- 0.03 mu mol/mg protein). Methionine levels were not significantly different between the 2 groups (C: 1.24 +/- 0.22 mu mol/mg protein; LPD: 1.03 +/- 0.27 mu mol/mg protein). A significant reduction (p ! 0.05) in hepatic GSH concentrations (C: 44 8 10 mu mol/mg protein; LPD: 17.4 +/- 4.3 mu mol/mg protein) was accompanied by an increase in lipid peroxidation (C: 0.13 +/- 0.01 mu mol/mg protein; LPD: 0.17 +/- 0.02 mu mol/mg protein; r = -0.62, p < 0.01). Conclusion: Hcy levels were reduced under a low-protein diet, resulting in modulated methyl balance and reduced GSH formation leading to increased susceptibility of hepatic cells to oxidative events. Copyright (C) 2009 S. Karger AG, Basel