Transmyocardial laser revascularization limits in vivo adenoviral-mediated gene transfer in porcine myocardium.
(41/1373)
OBJECTIVE: Transmyocardial laser revascularization (TMR) is emerging as a potential treatment option for patients with end-stage CAD, and adjuvant gene therapy may be helpful in further improving the results of the procedure. However, the effects of TMR on gene transfer are unknown. METHODS: Swine underwent left thoracotomy. TMR was performed to create five channels at 2-cm intervals in the anterolateral free wall of the left ventricle (LV) followed by injection of 1 x 10(9) plaque-forming units (pfu) of a replication-deficient adenovirus vector carrying the reporter gene beta-galactosidase (Ad.Pac beta-gal). An additional five direct injections of 1 x 10(9) pfu Ad.Pac beta-gal were made at 2-cm intervals in the posterolateral LV of each heart. Control animals underwent TMR alone/vehicle alone (n = 3) or empty virus alone/no treatment (n = 3) of the anterolateral/posterolateral LV, respectively. RESULTS: ELISA revealed significantly greater transgene expression in the direct Ad.Pac beta-gal injection versus TMR plus Ad.Pac beta-gal inject regions at both 3 (n = 6) (273.0 +/- 58.5 vs. 133.4 + 28.1 pg beta-gal/g protein, P = 0.02) and 7 days (n = 6) (180.0 + 59.9 vs. 56.7 + 18.1 pg beta-gal/g protein, P = 0.02) postoperatively. At 14 days postoperatively (n = 2), no transgene expression was detected in either region. No transgene expression was detected in any of the control regions at 3 days postoperatively. CD-18 staining revealed significantly greater inflammation in the TMR plus Ad.Pac beta-gal and TMR alone regions as compared to Ad.Pac beta-gal or vehicle (P < 0.001). CONCLUSIONS: Adenoviral-mediated gene transfer in conjunction with TMR is possible, although TMR appears to limit the degree of transgene expression attained as compared to direct intramyocardial injection alone, likely due to the greater immune response observed with the former. These findings may have important implications for therapeutic strategies aimed at combining TMR with gene therapy for CAD. (+info)
Analgesic effect of topical sodium diclofenac 0.1% drops during retinal laser photocoagulation.
(42/1373)
AIMS: To evaluate the analgesic effect of topical sodium diclofenac 0.1% during retinal laser photocoagulation. METHODS: 87 patients, 45 with proliferative diabetic retinopathy treated with two sessions of panretinal photocoagulation (group A), and 42 patients with non-proliferative diabetic retinopathy who underwent grid treatment of the posterior pole (19 bilaterally) (group B). Sodium diclofenac 0.1% or sodium chloride 0.9% drops were topically applied 30-135 minutes before laser treatment in a masked fashion. Patients who had two sessions were given the alternate drug in the second one. Pain level was evaluated immediately after laser treatment with the visual analogue scale (VAS). The results were statistically analysed. RESULTS: Patients in group A reported pain in 85/90 sessions (94%). The average pain level was 44.2% with sodium diclofenac 0.1% drops and 53.1% with sodium chloride 0.9% drops (p = 0.011 by paired t test). Patients in group B reported pain in only 16/60 sessions (26. 7%), and the pain level ranged from 10% to 60% regardless of the kind of drops used. There was no correlation in either group between level of pain and time interval from application of the drops to laser treatment (30-135 minutes) or average energy level used (100-500 mW). CONCLUSION: Sodium diclofenac 0.1% is useful for pain reduction and should be applied before panretinal photocoagulation. (+info)
Electric and laser energy for endoscopic surgery.
(43/1373)
Improvements in surgery have focused on refinements in the ability to dissect and limit blood loss. The electrosurgery unit (ESU) and laser (light amplification by stimulated emission of radiation) have been widely used in recent endoscopic surgery. ESU is a form of surgery in which high-frequency (100 kHz-5 MHz) electric currents are used to incise, destroy, and remove tissue and to seal blood vessels in order to maintain hemostasis. The use of lasers in surgery has added a new dimension to operative technique through increased precision, improved hemostasis, and less tissue manipulation. This paper aims to explain the basic principles and applications of electrosurgery and lasers. (+info)
Sensitive immunoassay of tissue cell proteins procured by laser capture microdissection.
(44/1373)
Coupling laser capture microdissection (LCM) with sensitive quantitative chemiluminescent immunoassays has broad applicability in the field of proteomics applied to normal, diseased, or genetically modified tissue. Quantitation of the number of prostate-specific antigen (PSA) molecules/cell was conducted on human prostate tissue cells procured by LCM from fixed and stained frozen sections. Under direct microscopic visualization, laser shots 30 microm in diameter captured specific cells from the heterogeneous tissue section onto a polymer transfer surface. The cellular macromolecules from the captured cells were solubilized in a microvolume of extraction buffer and directly assayed using an automated (1.5 hour) sandwich chemiluminescent immunoassay. Calibration of the chemiluminescent assay was conducted by developing a standard curve using known concentrations of PSA. After the sensitivity, precision, and linearity of the chemiluminescent assay was verified for known numbers of solubilized microdissected tissue cells, it was then possible to calculate the number of PSA molecules per microdissected tissue cell for case samples. In a study set of 20 cases, using 10 replicate samples of 100 laser shots per sample, the within-run (intraassay) SD was approximately 10% of the mean or less for all cases. In this series the number of PSA molecules per microdissected tissue cell ranged from 2 x 10(4) to 6. 3 x 10(6) in normal epithelium, prostate intraepithelial neoplasia (PIN), and invasive carcinoma. Immunohistochemical staining of human prostate for PSA was compared with the results of the soluble immunoassay for the same prostate tissue section. Independent qualitative scoring of anti-PSA immunohistochemical staining intensity paralleled the LCM quantitative immunoassay for each tissue subpopulation and verified the heterogeneity of PSA content between tissue subpopulations in the same case. Extraction buffers were successfully adapted for both secreted and membrane-bound proteins. This technology has broad applicability for the quantitation of protein molecules in pure populations of tissue cells. (+info)
Mediation of laser trabeculoplasty-induced matrix metalloproteinase expression by IL-1beta and TNFalpha.
(45/1373)
PURPOSE: Laser trabeculoplasty of the anterior uveal region of the trabecular meshwork induces sustained matrix metafloproteinase expression within the juxtacanalicular region of the meshwork. Studies were conducted to test the hypothesis that a factor mediates this response and to identify the factor. METHODS: Human anterior segment organ cultures were subjected to laser treatment using standard clinical parameters and were returned to culture for 8 hours. The resultant 8-hour-conditioned culture medium was then tested for factor activity by evaluating its ability to produce two typical trabecular responses to laser treatment, that is, to induce stromelysin expression or to trigger cell division, when applied to fresh organ cultures or to cell cultures. Confocal immunohistochemistry of the laser-treated organ cultures and western immunoblot analysis of the conditioned medium were used to evaluate changes in potential candidates for the factor activity. The ability of the interleukin (IL)-1 receptor antagonist (IL-1ra)- and of tumor necrosis factor alpha (TNFalpha)- blocking antibodies to eliminate the stromelysin induction was evaluated. RESULTS: Medium conditioned for 8 hours induced typical trabecular cell division in anterior segment organ cultures. Medium conditioned for 8 hours, but not for 30 minutes, induced typical increases in stromelysin expression in these organ cultures and in cell cultures. After 8 hours, both trabecular cells in laser-treated organ cultures and in the conditioned medium contained elevated levels of IL-1beta and TNFalpha. The laser-treated organ cultures contained elevated levels of IL-1alpha, but it was not secreted into the medium. The ability of conditioned media to induce stromelysin expression was partially blocked by either the IL-1ra- or the TNFalpha-blocking antibody. CONCLUSIONS: Laser trabeculoplasty induces the expression and secretion of both IL-1beta and TNFalpha within the first 8 hours after treatment. These cytokines then mediate increased trabecular stromelysin expression. Putatively, this initiates remodeling of the juxtacanalicular extracellular matrix, a likely site for the aqueous outflow resistance, and thus restores normal outflow facility. (+info)
Erbium: YAG laser ablation of retinal tissue under perfluorodecaline: determination of laser-tissue interaction in pig eyes.
(46/1373)
PURPOSE: To evaluate the effect of Er;YAG laser on pig retina using a perfluorodecaline/retina interphase with the goal of precisely determining the extent of retinal tissue ablation. METHODS: Free running (tau = 250 microsec) Er:YAG laser pulses were transmitted through a zirconium fluoride (ZrF4) fiber guarded by quartz rod (d = 1000 microm). Laser pulses were applied to the retinal surface of enucleated pig eyes. Eyes were mounted in a specially designed rotating sample holder. The fiber probe was elevated 1.0 +/- 0.3 mm above the retinal surface with perfluorodecaline serving as transmitting medium. The laser energy was applied in a circular pattern with a radius of 3.0 mm. Radiant exposures were set to 1, 3, 5, and 10 J/cm2. RESULTS: Tissue ablation linearly increased with radiant exposure from 3.2 +/- 3.7 microm at 1 J/cm2 up to 40.9 +/- 12.9 microm at 10 J/cm2. Thermal tissue changes extended 70 +/- 10 microm vertically into the retina and 25 +/- 5 microm horizontally. Distortion of outer photoreceptor segments was noticed when the retina was exposed to radiant exposures of 3 J/cm2 or higher. CONCLUSIONS: The Er:YAG laser in combination with perfluorodecaline produced precise ablation of the pig retina, which suggests the feasibility of this technique for safe ablation of epiretinal membranes. (+info)
Conization of the cervix using harmonic scalpel.
(47/1373)
Conization, as a surgical treatment for cervical intraepithelial neoplasm (CIN), is a good method that preserves reproductive functions. Technological developments have introduced a wide variety of energy sources for surgical procedures. Traditional cold knife conization has been replaced by laser conization and by the loop electrosurgical excisional procedure (LEEP). However, laser conization and LEEP have some disadvantages. Laser conization requires expensive equipment. LEEP induces electrocautery artifacts and cannot excise the cervical tissue as a single-piece, because of the various extensions and depths of lesion, so that evaluation of the margins is sometimes not possible. Laser conization and LEEP both generate smoke. The presence of smoke is not only inconvenient, but also dangerous. Harmonic Scalpel (HS), ultrasonic cutting and coagulation system, is a new surgical tool that cuts and coagulates using ultrasonic mechanical vibrations. Eleven women with CIN III underwent conization using HS. HS eliminated the major disadvantages of electrosurgery and laser surgery. No complications during conization were observed. Postoperative hemorrhage was noted in only one patient. Histological diagnosis was not affected by heat or ultrasound. This surgical method using HS is characterized by negligible bleeding, a good visual field not obscured by smoke and resection of an ideal shape that fits the size of the lesion. It is concluded that this method overcomes most problems associated with conization using conventional methods. (+info)
Supralaryngeal tubeless combined high-frequency jet ventilation for laser surgery of the larynx and trachea.
(48/1373)
We have developed a new technique of combined high-frequency jet ventilation (HFJV), characterized by simultaneous application of a low-frequency (LF) and a high-frequency (HF) jet stream. Tubeless supralaryngeal jet ventilation was delivered via a modified Kleinsasser laryngoscope. We studied 44 adults undergoing 45 elective surgical procedures of the larynx and trachea using a carbon dioxide laser during HFJV. Applied inspiratory oxygen ratios ranged from 0.4 to 1.0. Mean driving pressures of the HF and LF jet streams were 1.5 bar and 1.8 bar in adults, respectively. Mean duration of HFJV was 41 (range 10-180) min. HFJV resulted in mean PaO2 and PaCO2 values of 16.6 (range 9.8-26.9) kPa and 5.7 (3.0-7.6) kPa, respectively. Tubeless supralaryngeal HFJV was safe and effective in maintaining gas exchange in the presence of laryngeal or tracheal stenoses, providing optimal visibility of anatomical structures, offering maximum space for surgical manipulation, and avoiding the use of combustible material inside the larynx or trachea. (+info)