Microm In Group Research Articles

Protective effect of zinc over lead toxicity on testes.

To determine the effects of lead and zinc on testes. Randomized control trial. Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi, from August 2003 to December 2005. Sixty adult (90 days old) albino rats were obtained from animal house JPMC for the study and divided into 3 groups. Group A received injection normal saline 1 cc intraperitoneally daily for 8 weeks. Group B received lead chloride in a dose of 10 mg/kg body weight intraperitoneally daily. Group C received zinc chloride in a dose of 1 mg/kg body weight before half an hour of injection of lead chloride in a dose of 10 mg/kg body weight intraperitoneally daily so that to provide pre-treatment. On the day of completion of treatment the animals were sacrificed testes removed and fixed in Bouin's fluid. Testes were dehydrated in the ascending strength of alcohol, 5 mum thick sections were cut and stained with PAS Iron Hematoxylin. Student's t-test was used for statistical analysis with significance at p < 0.05. The mean diameter of seminiferous tubule was 291.91 + or - 1.18, 198.53 + or - 1.67 and 288.77 + or - 1.11 microm in groups A, B and C respectively. Diameter of seminiferous tubules decreased by 31.99% in group B (p < 0.001; CI 89.023 to 97.736) as compared group A and while group B comparing with group C, the diameter of seminiferous tubules was decreased by 31.25% (p-value = 0.076; CI -94.264 to -86.203). Mean thickness of germinal epithelium was 96.19 + or - 1.01, 50.69 + or - 1.20 and 94.94 + or - 0.54 microm in groups A, B and C respectively. Thickness of germinal epithelium decreased by 47.30 in group B (P < 0.001; CI 42.503 to 48.496) as compared to group A and while comparing group B with group C, the thickness of germinal epithelium was decreased by 46.61% (p=-44.25; CI -46.704 to -41.787). Zinc prevented toxic effects of lead on germinal epithelium in the albino rats.

Histological Analysis of Single Peripheral Nerve Fiber in Acute Nerve Elongation Process

To observe the histological alterations of single nerve fiber structures after nerve elongation by employing a rabbit peroneal nerve stretching model. 14 rabbits weighing mean 3. 0 kg (2.02-3.31 kg.) were used in the experiment. Two rabbits were used as control when only a sham operation was done (group one, 0% stretch). Acute stretching of the peroneal nerves to elongate them by 10% was done in 6 rabbits (group two, 10% elongation) and by 20% (group three, 20% elongation) in another 6 rabbits. All animals were evaluated by tissue staining technology in a teased-fiber study. The internodal lengths were measured, and nodes of Ranvier and Schmidt-Lanterman notch were observed. The nerve fiber length was increased after stretching. The mean internodal length was 1208.31 microm in group one, 1347.26 microm in group two, and 1411.35 microm in group three. Compared with the control group, mean internodal length was elongated by 11.50% in group two and 16.80% in group three. The difference was statistically significant. The node of Ranvier and Schmidt-Lanterman notch was wider in both group two and group three. Rupture of nerve fiber at the node of Ranvier was observed in group three. The peroneal nerve in rabbits can adapt to mild stretching by internodal length elongation. Elongation by 20% will cause structural rupture and therefore is the limit for nerve elongation.

Corneal aberrometric and refractive performance of 2 intrastromal corneal ring segment models in early and moderate ectatic disease

To evaluate and compare visual, refractive, and corneal aberrometric outcomes after implantation of 2 types of intrastromal corneal ring segments (ICRS) in eyes with early to moderate ectatic disease. Vissum Corporation-Instituto Oftalmológico de Alicante, Alicante, Spain. This retrospective analysis comprised consecutive eyes with grade I or grade II corneal ectasia (keratoconus, pellucid marginal degeneration, ectasia after laser in situ keratomileusis) that had Intacs (Group I) or KeraRings (Group K) ICRS implantation using femtosecond technology. Visual, refractive, and corneal aberrometric outcomes were analyzed and compared between groups over a 6-month follow-up. Group I had 17 eyes and Group K, 20 eyes. One month postoperatively, there was a statistically significant reduction in sphere in both groups (P<or=.02). At 6 months, there was a statistically significant reduction in manifest cylinder in Group K that was consistent with the significant reduction in corneal astigmatic aberration (both P = .04). The uncorrected distance visual acuity increased significantly in Group K (P = .04) but not in Group I; 41.18% of eyes in Group I and 52.94% in Group K gained 1 or more lines of corrected distance visual acuity. Both groups had significant corneal flattening (P<or=.02). At 1 month, the mean primary spherical aberration was -0.17 microm +/- 0.52 (SD) in Group I and 0.40 +/- 0.35 microm in Group K; the difference was statistically significant (P<.01). Astigmatism correction in early to moderate ectatic corneas was more limited with the Intacs ICRS, which induced negative primary spherical aberration in the initial postoperative period. No author has a financial or proprietary interest in any material or method mentioned.

A novel rat model of abdominal aortic aneurysm using a combination of intraluminal elastase infusion and extraluminal calcium chloride exposure

An ideal animal model of abdominal aortic aneurysm (AAA) is of great importance for clarifying unknown complex mechanisms of the pathogenesis. We introduce a new, simple technique to create reliable AAAs that simulate human aneurysms. Experimental models of AAAs were created in 71 rats by means of a 20-minute application of intraluminal elastase (30 U) and extraluminal calcium chloride (0.5M) in the 1-cm segment of infrarenal abdominal aorta (group EC, n = 26). A single application of elastase (group E, n = 24) or calcium chloride (group C, n = 21) was used as control. The treated aorta in each group was measured under physiologic conditions and harvested at 1 and 4 weeks. Successful AAA formation was defined as a dilation ratio >50%. Inflammatory response, elastolytic activity, and histology in the treated aorta were evaluated among the three groups. The surgical procedure in each group was similarly completed for approximate 30 minutes and performed without any technical failure or operative death. At 4 weeks, the dilation ratio and wall thickness were 94.8% +/- 9.9% and 125.4 +/- 5.6 microm in group EC, 43.3% +/- 6.3% and 149.6 +/- 6.5 microm in group E, and 10.9% +/- 4.2% and 152.9 +/- 7.2 microm in group C. The success rate of AAA formation in group EC (92.7%) was significantly higher than that in group E (25.0%) and group C (0.0%). Less elastin content in the aortic wall was observed in group EC. At 1 week, tumor necrosis factor-alpha and interleukin-1beta messenger RNA (mRNA) expressions were significantly upregulated, and CD3+ and CD11b+ cells were significantly infiltrated into the treated aorta of group EC, compared with groups E or C. Gelatinolytic activities and mRNA expressions of matrix metalloproteinase (MMP)-2 and MMP-9 were also significantly activated in group EC. The rat AAA model using a combination of intraluminal elastase infusion and extraluminal calcium chloride exposure is simple and easy to perform and is highly reliable and reproducible to create a saccular aneurysm similar to human AAAs. This model could be more useful to clarify AAA pathogenesis, mechanisms, and treatment interventions in experimental researches.

Femtosecond laser versus mechanical microkeratomes for flap creation in laser in situ keratomileusis and effect of postoperative measurement interval on estimated femtosecond flap thickness

To prospectively compare laser in situ keratomileusis (LASIK) flaps created with a femtosecond laser or a mechanical microkeratome and analyze the effect of the postoperative measurement interval on estimated femtosecond flap thickness using ultrasound (US) pachymetry. Department of Ophthalmology, University Hospital of Coimbra, and Coimbra Surgical Centre, Coimbra, Portugal. Flaps were created with a Hansatome Zero Compression microkeratome (Group 1), Zyoptix XP keratome (Group 2), or IntraLase 60 kHz femtosecond laser (Groups 3 and 4). Flap thickness was determined by intraoperative US pachymetry immediately after flap creation in Groups 1, 2, and 3. In Group 4, pachymetry was performed 20 minutes after the laser treatment. The main outcome measures were flap thickness and deviation from the target value. Eighty patients had LASIK for myopia or myopic astigmatism. The mean flap thickness was 149.1 microm +/- 24.9 (SD) in Group 1, 124.7 +/- 23.8 microm in Group 2, 143.1 +/- 18.4 microm in Group 3, and 115.5 +/- 12.5 microm in Group 4. The difference in flap thickness between Group 3 and Group 4 was statistically significant (P<.01). The flap thickness deviation from the target value was 22.8 microm in Group 1, 19.0 microm in Group 2, 26.1 microm in Group 3, and 10.4 microm in Group 4. Results indicate that the time of measurement after femtosecond affects the estimated flap thickness. Waiting 20 minutes after laser treatment permitted easier separation and may eliminate the effect of variable corneal dehydration on flap measurement by subtraction pachymetry.

Biomechanical and histological changes after corneal crosslinking with and without epithelial debridement

To test the biomechanical efficiency of corneal crosslinking with riboflavin without epithelial debridement (C3-R). Moscow Helmholtz Research Institute of Eye Diseases, Moscow, Russia. The left eyes of rabbits were crosslinked using standard crosslinking including epithelial removal (Group 1), using benzalkonium chloride-containing proxymetacaine eyedrops without epithelial removal (Group 2), or using preservative-free oxybuprocaine eyedrops without epithelial removal (Group 3). All left eyes received riboflavin solution and were irradiated with an ultraviolet-A double diode for 30 minutes (irradiance 3 mW/cm(2)). The animals were killed 1 day after crosslinking. Biomechanical and histological analyses were performed. Fourteen eyes were evaluated. There was a statistically significant increase in Young's modulus in Group 1 (102.45%) and in Group 2 (21.30%). In Group 3, no biomechanical changes were measured. Histology showed complete cell loss of keratocytes and endothelium in Group 1 and inhomogeneous keratocyte loss down to 200.0 microm in Group 2. No changes were observed in Group 3. Corneal crosslinking without epithelial debridement reduced the biomechanical effect by approximately one fifth compared with standard crosslinking, probably because of restricted and inhomogeneous stromal distribution of riboflavin. The cytotoxic damage was restricted to 200.0 microm stromal depth, which is an advantage over the standard method. Therefore, C3-R is not recommended for the routine treatment of keratoconus but primarily for cases with a corneal thickness less than 400.0 microm in which standard crosslinking cannot be used without serious risk to the endothelium.

Management of extensive subfoveal haemorrhage secondary to neovascular age-related macular degeneration

To evaluate the clinical outcomes of subfoveal haemorrhages secondary to neovascular age-related macular degeneration (AMD), which were treated with intravitreal recombinant tissue plasminogen activator (rTPA)/gas and anti-vascular endothelial growth factor (anti-VEGF) drug or with an intravitreal anti-VEGF monotherapy. This is a retrospective pilot study. Patients who received intravitreal rTPA/gas and anti-VEGF injections (n=20, bevacizumab or ranibizumab) were included in group A. Patients who refused prone positioning after rTPA/gas injections and were treated with an anti-VEGF monotherapy (bevacizumab) alone were included into group B (n=10). Changes in baseline visual acuity (VA, Snellen), central retinal thickness (CRT) and haemorrhage size were analysed. Mean baseline VA was 0.15+/-0.2 and 0.25+/-0.17 in groups A and B, respectively. At month 4, significant improvement in mean VA was observed in group A (mean difference: +0.1+/-0.14; P=0.003), and a stabilization in group B (mean difference: +0.008+/-0.2; P=0.94). CRT decreased significantly by 70 microm in group A (P=0.001) and by 84 microm in group B (P=0.03). The mean size of subfoveal haemorrhage in groups A and B was 20.2 mm(2) and 19.1 mm(2) at baseline and 0.0 mm(2) and 2.0 mm(2) at month 4, respectively. The anti-VEGF treatment rate was 1.6 in group A and 3.0 in group B. In patients with extensive subfoveal haemorrhage secondary to neovascular AMD, the combination therapy of rTPA/pneumatic displacement and anti-VEGF results in mean improvement of VA and stabilization of morphological parameters. If rTPA and pneumatic displacement combination is contraindicated, an anti-VEGF monotherapy may be performed to prevent further visual loss.

Evaluation of Corneal Topography With Orbscan II in First-degree Relatives of Patients With Keratoconus

To evaluate the corneal topographic characteristics of first-degree relatives of patients with keratoconus with corneal topography to determine the incidence of clinical keratoconus and topographic abnormalities. Between February and August 2006, Orbscan II analysis was done in 144 eyes of 72 cases who were first-degree relatives of patients diagnosed with clinical keratoconus. The findings were compared with preoperative Orbscan analyses of 52 clinically normal individuals who underwent laser in situ keratomileusis surgery and did not develop corneal ectasia in 3 years of follow-up. In 8 of the 72 first-degree relatives of patients with keratoconus, clinical keratoconus was diagnosed by the topographic pattern in Orbscan and clinical examination (group 1). The remaining 64 subjects (group 2) were compared with the control group (group 3). The central corneal thickness was 523.7 +/- 40.4 microm in group 2, whereas it was 546.3 +/- 33.1 microm in group 3 (P < 0.05). The central corneal thickness, thinnest pachymetric reading, posterior elevation value, distance between the greatest anterior/posterior elevation points, and corneal center, posterior best fit sphere (BFS) values, posterior BFS:anterior BFS ratio, and irregularity values were significantly different between group 2 and group 3 (P < 0.05). The keratoconus incidence was found to be 11% in first-degree relatives of patients with keratoconus as opposed to a reported incidence of keratoconus of 0.05% in the general population. In first-degree relatives of patients with keratoconus who did not have a topographic keratoconus pattern, abnormal corneal topographic values were detected. The asymptomatic relatives of patients with keratoconus should undergo a thorough preoperative analysis for subtle topographic abnormalities before any keratorefractive surgery.

Experimental study on fabricating Ni-Cr alloy coping with laser rapid forming

To probe the feasibility of fabricating Ni-Cr alloy coping with laser rapid forming (LRF). The digitalized model of coping was designed using the technology of reverse engineering and computer aided design (CAD) based on the abutment. The Ni-Cr alloy coping was fabricated with LRF. The gaps between the internal surface of coping and the external surface of abutment were measured respectively at the locations of occlusal surface edge, midpoint of axial wall and shoulder edge. The results were compared with the reference of 120 microm which was accepted generally to analyze the adaptation by statistical means. With statistical analysis of the t-test, the mean of gap width of each group, (82.60 +/- 13.58) microm for group A, (45.80 +/- 16.12) microm for group B, and (57.90 +/- 9.04) microm for group C, was less than 120 pm and the differences were statistically significant (t(A) = 8.71, t(B) = 14.56, t(C) =21.72, P <0.05). The Ni-Cr alloy coping with a thickness of 0.8 mm can be fabricated with LRF successfully and the adaptation can meet the reference of 120 microm.

Influence of Rifampin on Capsule Formation Around Silicone Implants in a Rat Model

This study investigated the effect of rifampin on the thickness of capsules around silicone implants by bactericidal activity against Stapylococcus epidermidis. Silicone blocks (1 x 1 cm) were placed into pockets created for each of the 40 rats included in the study. In group 1, the operation was performed under aseptic conditions. In group 2, standard S. epidermidis was inoculated into the pocket, whereas rifampin and S. epidermidis were applied in group 3. In group 4, only rifampin was applied topically on implants. After 12 weeks, the peri-implant capsules were removed and examined under a photomicroscope and a scanning electron microscope. The mean thickness of the capsules was 63.307 microm in group 1, 111.538 microm in group 2, 43.076 microm in group 3, and 30.384 mum in group 4. The differences between groups 2 and 3 and groups 2 and 4 were found to be statistically significant (p < 0.001). Rifampin appears to be an agent for preventing peri-implant capsule formation.

Comparison of Higher-order Aberrations between Eyes with Natural Supervision and Highly Myopic Eyes in Koreans

PurposeTo describe the characteristics and investigate the differences of higher-order aberrations (HOAs) between the eyes with a natural, uncorrected visual acuity (UCVA) of 20/12 and eyes with highly myopic eyes in Korean adults.MethodsThirty-one eyes of 20 subjects with UCVA of 20/12 (Group 1) and 54 eyes of 36 myopic patients with greater than -6 diopters (Group 2) were analyzed for type and magnitude of HOAs across a 6.0 mm pupil. HOAs were measured by Wavescan (VISX, Santa Clara, CA, USA) in natural scotopic conditions and were presented as root-mean-square (RMS:µm) in Belle aberration maps.ResultsThe mean spherical equivalent (SE) of manifest refraction was -0.15±0.25 D (range: +0.37 to -0.50 D) in Group 1 and -7.25±0.78 D (range: -6.00 to -9.25 D) in Group 2. The total root-mean-square (RMS) values of HOAs for Group 1 and Group 2 were 0.28±0.09 µm and 0.27±0.087 µm, respectively (P>0.05). The mean values of coma, trefoil, and spherical aberration were 0.14±0.091 µm, 0.14±0.089 µm, 0.091±0.059 µm in Group 1 and 0.16±0.077 µm, 0.14±0.073 µm, 0.082±0.059 µm in Group 2, respectively.ConclusionsThis study helped establish ocular aberration standards for those with natural supervision and those with highly myopic eyes among Koreans. Individuals with natural supervision had significant amounts of HOAs, and there was no significant difference in the amount of HOAs between the two groups. The index of higher-order aberrations may not be a perfect predictor of the amount of refractive error.

Central Corneal Thickness and Visual Field Progression in Patients With Chronic Primary Angle-closure Glaucoma With Low Intraocular Pressure

To determine the association of central corneal thickness (CCT) and visual field progression in patients with chronic primary angle-closure glaucoma (CPACG) with low intraocular pressure (IOP). Retrospective, comparative case series. A total of 163 eyes with CPACG and sustained IOP <18 mm Hg were included. Initial and three-year after mean deviation (MD) on Humphrey field analyzer and CCT with ultrasonic pachymetry were recorded. On the basis of the CCT value, the sample was split in two groups (group 1 <540 microm; group 2 > or =540 microm). Mean CCT was 525.8 +/- 11.6 microm in group 1 and 574.4 +/- 24.0 microm in group 2. There was no significant difference for initial MD (P = .979), but a significant difference was found between two groups for follow-up MD (P = .023). Patients with CPACG with a thinner cornea are at greater risk for visual field progression even if they maintain a low IOP after treatment.

Effect of laser in situ keratomileusis and laser-assisted subepithelial keratectomy on retinal nerve fiber layer thickness

To evaluate and compare the influence of laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratectomy (LASEK) on the peripapillary retinal nerve fiber layer (RNFL) thickness. Observational case series. Twenty nonglaucomatous patients with mild to moderate myopia were included. One eye in each patient was randomly selected to have LASIK (Group 1, n = 20), and LASEK was performed in the fellow eye (Group 2, n = 20). The RNFL thickness measurements were performed using optical coherence tomography (OCT) preoperatively and 1 day and 1 month postoperatively. The RNFL thickness parameters were compared using repeated-measures 1-way analysis of variance (ANOVA) followed by multiple comparison tests in both groups. The main outcome parameter was RNFL thickness as determined by OCT before and after LASIK and LASEK. The mean age of the patients was 21 years +/- 3.2 (SD). The mean preoperative spherical equivalent was -4.23 +/- 1.71 diopters (D) in Group 1 and -4.16 +/- 1.68 D in Group 2. The mean ablation depth was 73.35 +/- 27.85 microm and 66.35 +/- 23.64 microm in groups 1 and 2, respectively. In Group 1, the mean average RNFL thickness, inferior average, superior average, temporal average, and nasal average were 98.2 +/- 5.6 microm, 128.6 +/- 11.9 microm, 120.38 +/- 10.2 microm, 65. 8+/- 7.1 microm, and 80.5 +/- 18.8 microm, respectively. None of the RNFL thickness parameters or RNFL ratios were found to have a significant change after surgery. In Group 2, the average RNFL thickness, inferior average, superior average, temporal average, and nasal average were 98.47 +/- 5.9 microm, 128.38 +/- 14.3 microm, 125.1 +/- 8.8 microm, 66.4 +/- 8.2 microm, 73.6 +/- 15.8 microm, respectively. No significant change was observed in any of the parameters following surgery. No significant alterations were noted in the RNFL parameters following LASIK or LASEK. Laser in situ keratomileusis and LASEK did not significantly affect the RNFL thickness parameters postoperatively.

Thickness Changes in the Fovea and Peripapillary Retinal Nerve Fiber Layer Depend on the Degree of Myopia

PurposeTo investigate changes in the thickness of the fovea and peripapillary RNFL associated with myopia.MethodsSixty-five Korean adults (for a total of 130 eyes) between 23 and 26 years of age were selected as test subjects. Thirty-eight test subjects were male, and 27 were female. Subjects with glaucoma or other identified ocular diseases were excluded. Patients whose manifest refraction measurement values ranged between 0 to -2D were classified as group one (emmetropia and low myopia), those between -2 to -5D were classified as group two (moderate myopia), and those more than -5D were classified as group three (high myopia). Using the OCT, the thickness of the fovea and peripapillary RNFL were measured for every subject.ResultsThe thicknesses of the fovea for each of three groups were 142.16±8.99 µm in group one (45 eyes), 153.58±17.63 µm in group two (43 eyes) and 158.86±11.93 µm in group three (28 eyes). The data showed significant differences in fovea thickness between the groups. The average thicknesses of the peripapillary RNFL for each of three groups were 113.29±10.80 µm in group one, 103.85±14.48 µm in group two and 100.74±9.15 µm in group three. A statistically significant difference was found between group one and the other groups (p<0.05).ConclusionsAs the level of myopia increased, the thickness of the fovea also increased, while the thickness of the peripapillary RNFL decreased. Therefore, when interpreting OCT results in the clinic, careful consideration should be given to various changes associated with myopia.

Ultrastructural comparison of penile cavernous tissue between hypertensive and normotensive rats

Our aim was to compare the ultrastructure of penile cavernous tissue in the spontaneous hypertensive rat (SHR) and normotensive rat, and study the relation of blood pressure with erectile function. After injection of apomorphine (APO), penile erectile frequency in 16-week-old SHR (group A) and Wistar-Kyoto rat (WKY) (group B) was observed and noted. The ultrastructure of the penile cavernous tissue was studied by scanning electron microscope and transmission electron microscope. The mean blood pressures were significantly higher in group A than in group B (P=0; 171.20+/-10.94 and 117.60+/-12.38, n=5, for group A and group B, respectively). After treatment of the two groups with APO, the erectile frequency in group A was significantly less than in group B (P=0.007; 0.40+/-0.55 and 2.40+/-1.14, n=5, for group A and group B, respectively). Significant ultrastructural pathological changes were observed in the tunica albuginea and penile cavernous tissue of SHR. The elastic fibers were decreased and the collagen fibers of the sinusoid were increased in group A. The tunica albuginea thickness (mean+/-s.d.) was 100.20+/-7.22 microm and 126.00+/-7.65 microm in group A and group B, respectively. The tunica albuginea of group A was significantly thinner than that in B (P=0.001). Some endothelial cells and smooth muscle cells exhibited damaged mitochondria, and endoplasmic reticulums and Schwann cells were degenerated in group A. Although the function of penile erection might be affected by a secondary effect related to endothelial dysfunction of hypertension, these ultrastructural pathological changes of the penile cavernous tissue might also be one of the important mechanisms of erectile dysfunction caused by hypertension.

Central corneal thickness and vascular risk factors in normal tension glaucoma

Normal tension glaucoma (NTG) has been shown to be associated with reduced central corneal thickness (CCT). The association of NTG with vascular risk factors is well documented. It has been postulated that a subset of NTG patients are misclassified due to incorrect intraocular pressure measurements on thin corneas. The aim of this study was to establish whether corneal thickness in NTG differs between patients with vascular risk factors specific to NTG and those without. The study comprised a retrospective analysis of 108 eyes of 54 patients with NTG and 54 patients with primary open-angle glaucoma (POAG). Corneal thickness was measured in all patients. Vascular risk factors were recorded. Patients with NTG were divided into two groups depending on the presence (group A) or absence (group B) of vascular risk factors. The mean CCT was 549 +/- 34 microm in patients with POAG and 528 +/- 31 microm in patients with NTG (p = 0.001). Mean CCT was 512 +/- 31 microm in group A (n = 13) and 533 +/- 31 microm in group B (n = 41) (p = 0.034). A total of 40.9% of those with thin corneas (n = 22) had vascular risk factors versus only 12.5% of those with CCT within the normal range (n = 32) (p < 0.05). Central corneal thickness in NTG was significantly lower than in POAG and corneas were thinner in NTG patients with vascular risk factors than in those without. Vascular risk factors were significantly more common in patients with thin corneas. The finding of reduced corneal thickness in NTG does not obviate the need to consider vascular risk factors in the pathophysiology of the disease.

Qualitative microanalysis of ions and ultrastructural changes in dentin exposed to laser irradiation and to metal salts solution

This study evaluated the ultrastructural changes in dentin after treatment with the Nd:YAG laser and/or metal salt solutions and verified the presence of Sn++, Sr++, and F- in dentin structure. Sixty dentin disks were randomly divided into groups (n = 10): (I) control (no treatment), (II) Nd:YAG (1.5 W, 100 mJ, 15 Hz, 125 J/cm2), (III) 10% SnF2 aqueous solution for 30 minutes, (IV) Nd:YAG+10% SnF2 aqueous solution for 30 minutes, (V) 10% SrCl2 toothpaste for 30 minutes, (VI) Nd:YAG+10% SrCl2 toothpaste for 30 minutes. Then, all samples were prepared for scanning electron microscopy (SEM) and the samples from Groups I to IV for the energy dispersive X-ray microanalysis (EDX). SEM evaluation revealed occluded dentinal tubules and a dentin surface altered by the laser irradiation. The EDX microanalysis revealed Sn++ at a depth of 250 microm in Group IV and not deeper than 100 microm in Group III. In Group V, Sr++ was not deeper than 50 microm, but it could be detected at a depth of 500 microm in Group VI. F- was found only in Group IV. Ultrastructural changes caused by laser irradiation can increase dentin uptake of Sn++, Sr++, and F-.

The influence of pupil center shift on wavefront-guided laser in situ keratomileusis

To evaluate the pupil center shift quantitatively after pupil dilation and to investigate its influence on the outcome of wavefront guided LASIK. Sixty-three eyes in 32 myopic patients with order RMS higher than 0.35 or were divided into groups A and B, and the Zyoptix LASIK was applied to the patients of both groups In group A, pupil center was used as the center of ablation, while in group B the ablation center was adjusted based on the pupil center shift. A (0.173 +/- 0.114) mm mean pupil center shift was observed in this study, with the maximum 0.51 mm. At 3 months after the operation, there was no significant difference in visual acuity and refraction power between the two groups. However, the reduction of coma was (0.025 +/- 0.137) microm and (0.097 +/- 0.118) microm in groups A and B respectively (t = 2.131, P = 0.037). The change in spherical aberration was significantly different between the two groups. Pupil center shift after dilation is common. Adjustment of ablation center based on the shift may improve the correction of coma.

Effects of long-term passive smoking on the diameter of glomeruli in rats: Histopathological evaluation.

Long-term smoking increases the risk of renal diseases and it also causes the progression of the diseases. The aim of this study was to evaluate the effects of smoking on glomeruli in healthy rats exposed to long-term passive smoking for a short period of time after birth. Sixty-five rats were randomly assigned into four groups. Groups 1 (18 males) and 2 (18 females) were exposed to smoke, whereas groups 3 (15 males) and 4 (14 females) were not exposed to smoke. Overall, 130 renal units were evaluated, and diameters of 10 different glomeruli were measured. The renal and bodyweights of the rats were measured. The diameter of the glomeruli was 95.51 +/- 9.25 and 100.91 +/- 4.06 microm in groups 1 and 3, respectively (P < 0.05). It was 97.32 +/- 4.06 and 98.86 +/- 6.25 microm in groups 2 and 4, respectively (P > 0.05). Irrespective of the sex, the diameter of the glomeruli was 96.42 +/- 7.15 microm in smokers and 99.92 +/- 5.56 microm in non-smokers (P < 0.05). The renal weights of the male rats affected by smoke were significantly lower than that of those that were not affected by smoke (P < 0.05). Bodyweights of male rats affected by smoke were significantly lower that of those not affected (P < 0.05). There was a weak correlation between the diameter of the glomeruli and the bodyweights of male rats affected by smoke (r = 0.474, P < 0.05). We conclude that passive smoking might have a negative affect on renal morphometry and body growth.

Prophylactic anti-inflammation inhibits cigarette smoke-induced emphysema in guinea pigs.

In this study, the effect of prophylactic anti-inflammation on the development of smoke-induced emphysema was investigated. Young male guinea-pigs aged 1.5-2 months (weighing 198.3+/-26.9 g) were randomly divided into 4 groups: group A (cigarette smoke exposure only), group B (cigarette smoke exposure plus pentoxifylline-rich (PTX, 10 mg/d) forage feeding), group C (cigarette smoke exposure plus intermittent cortical steroid injection (Triamcinolone acetonide, 3 mg, i.m., every three weeks) and control group (group D: animals with sham smoke exposure, raised under the same conditions). Animals in group A, B and C were exposed to smoke of cigarettes for 1 to 1.5 h twice a day, 5 days a week. All animals were killed at the 16th week and followed by morphometrical analysis of the midsagittal sectioned lung slices. Smoke exposure of 16 weeks resulted in visible emphysematous development in Group A but not in Group B and C. It was evidenced by the indicator of air-space size, mean linear intercept (Lm): 120.6+/-16.0 microm in Group A; 89.8+/-9.2 microm in Group B and 102.4+/-17.7 microm in Group C. The average Lm in either group B or group C was shorter than that in Group A (ANOVA and Newman-Keuls test, F=8.80, P=0.0002) but comparable to that (94.8+/-13.2 microm) in group D (P>0.05). It is concluded that long-term prophylactic anti-inflammation inhibits pulmonary emphysema induced by cigarette smoking in the guinea pigs.