Assisted hatching in mouse embryos using a noncontact Ho:YSGG laser system.

Purpose: A noncontact holmium:yttrium scandium gallium garnet (Ho:YSGG) laser system has been designed and tested for the micromanipulation of mammalian embryos. The purpose of this preliminary investigation was to determine the effectiveness of this laser for assisted hatching and evaluate its impact on embryo viability. The Ho:YSGG system, utilizing 250-microsecond pulses at a wavelength of 2.

Root canal preparation using the second harmonic KTP:YAG laser: a thermographic and scanning electron microscopic study.

Thermal and microstructural events resulting from KTP laser use during root canal preparation were investigated in 30 extracted single-rooted human teeth. In the first section of this study, thermal events occurring on the root surfaces of 18 teeth during and after exposure of the root canal were measured using thermography. A variety of parameters were used to determine settings that would be effective without causing thermal damage to the periodontal ligament.

Photodynamic laser cyclodestruction with chloroaluminum sulfonated phthalocyanine (CASPc) or Photofrin (PII) vs. Nd:YAG laser cyclodestruction in a pigmented rabbit model.

Background And Objective: To investigate Photofrin (PII) and CASPc for photodynamic therapy (PDT) of the ciliary body in rabbits.

Study Design/materials And Methods: PII (10 mg/kg) or CASPc (1 mg/kg) was given by ear vein. Pharmacokinetics were studied in frozen sections by fluorescence microscopy (CCD camera based low light detection system with digital image processing) at 1 and 24 h (8 rabbits; 16 eyes).

Effect of freezing on the relative escape force of sperm as measured by a laser optical trap.

Objective: To determine the possible effect of freezing on sperm escape force as measured by laser trap.

Design: Controlled clinical study.

Setting: Normal volunteers, academic setting.

Rat reproductive performance following photodynamic therapy with topically administered Photofrin.

A rat animal model was used for comparing the photodynamic efficacy of two formulations of topically administered Photofrin in the uterus: 0.7 mg/kg Photofrin and 0.7 mg/kg Photofrin + 4% Azone, a penetration-enhancing agent.

Photomedicine of the endometrium: experimental concepts.

Gynaecological photomedicine offers new diagnostic and therapeutic methods based on the interaction of light with the reproductive organs. One example is photodynamic therapy (PDT) in which photosensitizers are applied systemically or topically for selective endometrial ablation. Several studies describing the potential use of PDT for this application are reviewed.

Thermal effects of CO2 laser on the pulpal chamber and enamel of human primary teeth: an in vitro investigation.

Background And Objective: Thermal effects of direct exposure of the pulp chamber to CO2 laser irradiation were evaluated and potentially safe parameters for its clinical application were determined.

Study Design/materials And Methods: Using conventional methods, the pulp chambers of freshly extracted primary cuspids were exposed and then subjected to CO2 laser irradiation at the following parameters: 2, 4, 6, 8, 10, 15, and 20 Watts power settings; 0.76 mm diameter spot size; total energy densities between 4-1,058 J/cm2; exposure time between .

Photodynamic destruction of endometrial tissue with topical 5-aminolevulinic acid in rats and rabbits.

Objective: The goal of this study was to determine the optimal parameters for photodynamic endometrial destruction with topically applied 5-aminolevulinic acid, a precursor for the endogenous synthesis of the fluorescent photosensitizer protoporphyrin IX.

Study Design: 5-Aminolevulinic acid pharmacokinetics were measured in rat and rabbit models by analyzing tissue frozen sections 3 to 12 hours after topical administration. Dose-response studies were conducted for 100 to 400 mg/ml 5-aminolevulinic acid.

Differential vascular response to laser photothermolysis.

Individual blood vessels in the chick choriallantoic membrane were selectively coagulated through photothermolysis, using pulsed laser irradiation at 585 nm. Pulse durations were chosen to be 0.45 ms and 10 ms, which correspond to the thermal relaxation times in blood vessels of 30 microns and 150 microns diameter, respectively.

Relative force of human epididymal sperm.

Objective: To assess the relative escape force of human epididymal sperm using a laser generated optical trap and compare it with that of human ejaculated sperm.

Design: Evaluation of the relative force generated by epididymal and ejaculated sperm using an 800-nm laser-generated optical trap system (titanium-sapphire, model 899-01; Coherent Innova, Palo Alto, CA).

Setting: University-based facility at the Beckman Laser Institute and Medical Clinic and Center for Reproductive Health, University of California, Irvine.

Benzoporphyrin derivative: a potent photosensitizer for photodynamic destruction of rabbit endometrium.

Objectives: To determine the optimal pharmacokinetic characteristics for photodynamic endometrial destruction using topically applied benzoporphyrin derivative and to evaluate long-term morphologic effects in a rabbit model.

Methods: Benzoporphyrin derivative pharmacokinetics were measured by analyzing frozen tissue sections 1.5-12 hours following topical administration.

Directed movement of chromosome arms and fragments in mitotic newt lung cells using optical scissors and optical tweezers.

A pulsed-laser microbeam at 532 nm wavelength (optical scissors) and a laser-induced optical trap at 1064 nm wavelength (optical tweezers) have been successively combined to dissect and manipulate chromosomes in live newt lung epithelial cells. These preliminary experimental results demonstrated that chromosome fragments dissected by laser microbeam surgery, regardless of their size, could be easily pulled or rotated by optical forces when positioned at the periphery of the mitotic spindle. In addition, chromosome arms which were not subjected to laser microsurgery also could be moved with the optical tweezers at the spindle periphery.

Intravascular ultrasound imaging after excimer laser angioplasty.

To help elucidate the mechanism of excimer laser coronary angioplasty (ELCA), intravascular ultrasound (IVUS) imaging was performed in 19 of 29 patients who were treated with ELCA. The results were compared with a non-randomized control group of 18 patients who had IVUS studies both before and after PTCA alone. After ELCA alone, lumen diameter (1.

Vasoreactivity and structure of human coronary arteries irradiated by excimer laser.

In this study the effects of excimer laser (308 nm) angioplasty on arteries have been studied. We report histology and vasoreactivity properties of human atherosclerotic and normal coronary arteries and bovine coronary arteries after exposure to pulsed excimer laser irradiation. Segments of isolated and pharmacologically active human coronary arteries were obtained within 5-8 hr postmortem.

Regional fat distribution as risk factor for clinically diagnosed gallstones in middle-aged men: a 25-year follow-up study (the Zutphen Study).

Obesity is considered to be an important risk factor for the formation of gallstones. The relationship is well established for women but not for men. In a long-term follow-up study of middle-aged men the relationship between various markers of obesity and the incidence of clinically diagnosed gallstones during 25 years of follow-up was studied.

Reproductive history and cancer of the biliary tract in women.

Although reproductive factors have been shown to be related to the composition of bile and functioning of the biliary system, their relationship with biliary tract cancer has not been studied in detail. Between 1984 and 1987 we conducted a case-control study of 75 women with cancer of the biliary tract and 252 controls from the general population. An interviewer-administered questionnaire was used to collect information on reproductive history.

Parametric study of the forces on microspheres held by optical tweezers.

Optical-trapping forces exerted on polystyrene microspheres are predicted and measured as a function of sphere size, laser spot size, and laser beam polarization. Axial and transverse forces are in good and excellent agreement, respectively, with a ray-optics model when the sphere diameter is ≥ 10 µm. Results are compared with results from an electromagnetic model when the sphere size is ≤ 1 µm.

Thoracoscopic laser ablation of pulmonary bullae. Radiographic selection and treatment response.

The purpose of this study was to develop objective preoperative selection methods for predicting outcome in patients undergoing thoracoscopic laser ablation of emphysematous pulmonary bullae. Initial radiographic presentation was correlated with physiologic function both before and after the operation in 24 patients entered into a prospective clinical protocol for evaluation of carbon dioxide laser treatment of emphysematous pulmonary bullae. Nineteen surviving patients underwent follow-up evaluation 1 to 3 months after the operation.

Exposure of human spermatozoa to the cumulus oophorus results in increased relative force as measured by a 760 nm laser optical trap.

Spermatozoa change their movement characteristics in response to different environmental conditions. To investigate the relative force of spermatozoa exhibiting different motility patterns, a laser optical trap was used. A laser beam at 760 nm was directed through a microscope objective and focused above the spermatozoa to create a three-dimensional optical trap.

Opening of the mouse zona pellucida by laser without a micromanipulator.

A contact-free laser system is described for ablation of the embryonic mouse zona pellucida using a pulsed excimer 308 nm laser. Effects on further embryonic development were evaluated. Zonae of 8- to 16-cell mouse embryos were either lased (n = 189), zona-drilled with acidified Tyrode's solution (n = 183) or left zona-intact (n = 188).

Astral and spindle forces in PtK2 cells during anaphase B: a laser microbeam study.

Rat kangaroo kidney epithelium (PtK2) cells develop prominent asters and spindles during anaphase B of mitosis. It has been shown that severing the spindle at early anaphase B in living PtK1 cells results in a dramatic increase in the rate of pole-pole separation. This result suggested that the asters pull on the spindle poles, putting tension on the spindle, while the spindle acts as a governor, limiting the rate of pole separation.

Zona opening with 308 nm XeCl excimer laser improves fertilization by spermatozoa from long-term vasectomized mice.

Spermatozoa from long-term vasectomized mice have greatly reduced fertilizing ability in vivo and in vitro, which makes this a useful animal model for male factor infertility. The purpose of this study was to evaluate the 308 nm XeCl excimer laser for opening the zona pellucida to enhance the fertilization rate with spermatozoa from vasectomized males. Inseminating zona-intact (control) oocytes with 5 x 10(6) spermatozoa/ml resulted in only 6% fertilization and 33.

Optical trapping for chromosome manipulation: a wavelength dependence of induced chromosome bridges.

Using a tunable titanium-sapphire laser, we have compared different wavelengths (from 700 to 840 nm) for their utility in optical trapping of chromosomes in mitotic rat kangaroo Potorous tridactylus (PtK2) cells. It was found that irradiation with a near-infrared light induces the sticking together of chromosome shoulders. The attached chromatids failed to separate, or separated with significant delay and formed a chromosome bridge during anaphase.