Effects of Intracameral Drugs and Dyes on Corneal Endothelial Cell Apoptosis in a Rat Model: An In Vivo and In Vitro Analysis.

Objectives: To evaluate the effects of intracameral drugs and dyes on rat corneal endothelial apoptosis and cell morphology. Materials and Methods: The right eyes of 72 rats were injected intracamerally with 1% lidocaine, 0.01% adrenaline, triamcinolone acetonide (TA) 4 mg/mL, 1% trypan blue (TB), 0.5% indocyanine green (ICG), and fortified balanced salt solution as control. Corneal samples were taken 1 day and 1 week post-injection. Corneal endothelial apoptosis was assessed by the TUNEL technique, and the ratio of apoptotic cells in each group was compared with the control. Corneal endothelial cell morphology was evaluated in each specimen by transmission electron microscopy. Results: The mean apoptotic endothelial cell ratio was significantly higher at 1 day and 1 week after intracameral adrenaline injection when compared to controls (p=0.03 and 0.021, respectively). TB caused a significantly higher apoptotic cell ratio when compared to controls at 1 week after injection (p=0.043). Lidocaine caused a higher apoptotic cell ratio compared to TA and ICG at 1 week, although not statistically significant (p=0.058, 0.09, 0.69, respectively). In all experimental specimens, transmission electron microscopy showed morphological changes associated with apoptosis. Conclusion: This study showed that intracameral adrenaline, TB, and lidocaine injections may have toxic effects on corneal tissue, as indicated by ultrastructural and histopathological alterations. Therefore, these agents should be used with caution in intraocular surgery.

Human Breast Milk Drops Promote Corneal Epithelial Wound Healing.

PURPOSE: To investigate the effects of human breast milk on corneal epithelial wound healing. METHODS: The effects of human breast milk on epithelial healing is compared with autologous serum and artificial tears on 24 female Bal-b/C mice. A central corneal epithelial defect was created using a 2 mm trephine. Four groups were formed. By a random pick-up, topical human breast milk 4 × 1 was given to Group 1, topical mouse autologous serum 4 × 1 was applied to Group 2, and preservative-free artificial tears 4 × 1 was applied to Group 3.Group 4 was evaluated as control. Biomicroscopical examination was performed on days 1, 2, and 3. Mice were sacrificed on the third day. Histopathological and electron microscopic examinations were performed as well. RESULTS: The fastest and best healing group was Group 1, followed by Group 2. Re-epithelization was not complete even at the end of the second day in groups 3 and 4. CONCLUSIONS: The rich content of human breast milk may be an alternative to epithelial healers and artificial tears.

Comparison of efficacy of topical phenytoin with hypericin in second-degree burn wound healing: an experimental study in rats.

BACKGROUND: This experiment was performed to compare the effects of Phenytoin (PHT) and Hypericin (HP) cream on healing of burn wounds in rats. MATERIAL AND METHODS: Twenty rats were divided into 3 groups and second-degree burn wounds were created. The burn wounds in the first, second, and third groups were covered twice daily with PHT cream, HP cream, and saline (control), respectively. At the end of days 3, 7, 14, and 21, full-thickness skin biopsies were done for histopathologic and immunohistochemical analyses. RESULTS: Histopathologic evaluations at the 14th day showed that re-epithelialization scores were greater in the HP group than the PHT group, but on day 21, re-epithelialization scores were higher in the PHT group than the HP group. Collagen content on days 3 and 14 in the PHT group was found to be higher than in the HP group. Well-vascularized granulation tissue on day 7 in the PHT group was higher than in other groups. HP and PHT groups had a significant increase in VEGF and TGF-b expression in burn wound healing area compared to the control group on all days. CONCLUSIONS: Topical application of HP can promote re-epithelialization in burn wounds to shorten the wound healing time for superficial burns. Phenytoin, on the other hand, contributes to healing by increasing vascularized granulation tissue and collagen synthesis through re-epithelialization. The increased VEGF and TGF-b expression following PHT and HP treatment strongly indicate that PHT and HP treatment promotes VEGF and TGF-b production and action in the burn wound area.

Clear lens phacoemulsification in Alport syndrome: refractive results and electron microscopic analysis of the anterior lens capsule.

PURPOSE: To report the ocular findings of patients with Alport syndrome and the results of clear lens extraction in this patient group. METHODS: Twenty-three eyes of 15 patients with a diagnosis of Alport syndrome were included in this study. Clear corneal phacoemulsification and intraocular foldable lens implantation was performed in eyes with indeterminate refractive errors and/or poor visual acuity and anterior capsule samples were analyzed with electron microscopy. RESULTS: All patients had a history of hereditary nephritis and/or deafness as systemic involvement. Ophthalmologic examination revealed anterior lenticonus with high myopia and/or irregular astigmatism in all patients. The mean best-corrected visual acuity (BCVA) was 0.67 ± 0.17 logMAR (range 1.0-0.4) preoperatively and 0.17 ± 0.08 logMAR (range 0.3-0.0) postoperatively. Postoperative refractive lenticular astigmatism dramatically decreased and no ocular complications arose during the follow-up period. Transmission electron microscopic analysis of the lens capsules supported the diagnosis of Alport syndrome. CONCLUSIONS: Clear lens phacoemulsification and foldable intraocular lens implantation is a safe and effective therapeutic choice for the management of uncorrectable refractive errors and low visual acuity due to anterior lenticonus in patients with Alport syndrome.

Minocycline treatment inhibits lipid peroxidation, preserves spinal cord ultrastructure, and improves functional outcome after traumatic spinal cord injury in the rat.

STUDY DESIGN: A prospective, randomized experimental research. OBJECTIVE: To evaluate the short- and long-term neuroprotective effects of minocycline on the secondary injury process of an experimental traumatic spinal cord injury (SCI) model. SUMMARY OF BACKGROUND DATA: Traumatic SCI is a devastating problem of health that results in high morbidity and mortality rates. The loss of function after SCI results from both the primary mechanical insult and the subsequent, multifaceted secondary response. METHODS: A total of 80 adult male Spraque-Dawley rats (breeded by the Baskent University Animal Research Center) were randomly divided into 4 groups. A T10 contusion injury was produced by using modified Allen technique in all groups except the control group. No medication was administered to the rats in the trauma group. Minocycline was administered intraperitoneally and intravenously to the treatment groups. Short-term and/or long-term neuroprotective effects of minocycline on the lipid peroxidation (malondialdehyde, glutathione), apoptosis (terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling), ultrastructure of spinal cord (tissue electron microscopy), and behavioral assessments (Basso-Beattie-Bresnahan) were evaluated. RESULTS: As compared with the trauma group, tissue malondialdehyde and glutathione levels demonstrated that minocycline significantly diminishes lipid peroxidation. Electromicroscopic study showed that minocycline preserves the ultrastructure of spinal cord tissue in the early post-traumatic period. Minocycline treatment significantly reduced the number of terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling positive cells both 1 day and 28 days after SCI. Behavioral assessments showed significant improvement in the hind limb functions of minocycline receiving rats starting 7 days after the SCI. Any statistically significant difference was not found between intraperitoneal or intravenous routes for minocycline injection. CONCLUSION: Minocycline is neuroprotective and contributes to functional improvement after traumatic SCI by eliminating the destructive process of secondary injury. Having both satisfying anti-inflammatory and antiapoptotic effects in experimental models, it promises to be of therapeutic use in human SCI.

Ocular pharmacokinetics, safety and efficacy of intracameral moxifloxacin 0.5% solution in a rabbit model.

PURPOSE: This study was carried out to determine the ocular pharmacokinetics, efficacy and potential endothelial toxicity of moxifloxacin (MF) after a single intracameral bolus injection of 500 µg/0.1 ml in a rabbit model. MATERIALS AND METHODS: Forty-eight eyes of 24 New Zealand White Rabbits were separated into six groups, each including four rabbits. 0.1 ml of 0.5% intracameral moxifloxacin (500 µg) injection was injected to the right eyes and 0.1 ml of balanced salt solution to the left eyes (control). Aqueous humor (AH) and vitreous samples were collected at the 0.5th, 1st, 3rd, 6th, 12th and 24th hours from both eyes of group 1, 2, 3, 4, 5 and 6, respectively. MF concentrations were determined by high performance liquid chromatography. These were compared with the minimum inhibitory concentrations (MIC) and mutant prevention concentrations (MPC) for frequent endophthalmitis pathogens. Electron and light microscopical evaluation of the corneas were performed. RESULTS: Moxifloxacin reaches higher concentration than the MIC of all common endophthalmitis pathogens in the AH and exceeds the mutant prevention concentration levels for Streptococcus pneumonia, Streptococcus viridans, flouroquinolone susceptible Coagulase-negative staphylococcus and flouroquinolone susceptible Staphylococcus aureus for 6 h. The half-life of moxifloxacin in the AH was 2.2 h. Electron and light microscopic evaluation revealed no noticeable sign of toxicity. CONCLUSIONS: Peroperative intracameral moxifloxacin injection for endophthalmitis prophylaxis is a safe and effective method in uncomplicated phacoemulsification surgery.

Structural consequences after intravitreal bevacizumab injection without increasing apoptotic cell death in a retinopathy of prematurity mouse model.

PURPOSE: To evaluate the effect of different bevacizumab concentrations on retinal endothelial cell proliferation, retinal structures and apoptotic activity after intravitreal injection in a retinopathy of prematurity (ROP) mouse model. METHODS: A total of 35 of C57BL/J6 mice were exposed to 75±2% oxygen from postnatal day 7 to postnatal day 12. On day 12, 10 mice (group C) were injected with 2.5 µg intravitreal bevacizumab (IVB), 11 mice (group D) were injected with 1.25 µg IVB, and 14 mice (group E) were injected with 0.625 µg IVB in one eye. The contralateral eyes were injected with isotonic saline (control group=group B). Four nonexposed mice served as negative controls (group A). Neovascularization was quantified by counting the endothelial cell proliferation on the vitreal side of the inner limiting membrane of the retina. Histological and ultrastructural changes were examined by light and electron microscopy. Terminal deoxynucleotidyl transferase deoxy-UTP-nick end labelling (TUNEL) was used to detect apoptosis. RESULTS: The endothelial cell count per histological section was lower in groups C (p<0.0001), D (p<0.0001) and E (p<0.0001) compared with the control group B. Histological evaluation showed no retinal toxicity in any group. Electron microscopy revealed hyperoxia-induced mitochondrial dysmorphology in group B. Mitochondrial dysmorphology displayed dose-dependent gradual increase in IVB-injected eyes. Intravitreal bevacizumab induced no significant increase in apoptotic cell death. CONCLUSION: Bevacizumab suppresses endothelial cell proliferation in a ROP mouse model. In addition to hyperoxia-induced mitochondrial dysmorphology of C57BL/J6 retina, morphological findings implicate further mitochondrial vulnerability because of bevacizumab without increase in apoptotic cell death.

Antioxidant prophylaxis for cellular injury in ovarian surface epithelium resulting from CO2 pneumoperitoneum in a laparoscopic rat model.

OBJECTIVE: Selective cytoprotective functions of vitamin E, N-acetyl-L: -cysteine, and amifostine have been used as a preventer of ischemia injury by expelling the free oxygen radicals leading to stabilization of the cellular membranes. The purpose of this experimental study was to investigate the oxidative stress related to cellular injury in ovarian surface epithelium and the effect of prophylaxis with an anti-oxidant using laparoscopic rat model. DESIGN: Laparoscopic rat model. MATERIALS AND METHODS: Randomly allocated 40 Wistar Albino female rats have been used for the pneumoperitoneum model which was constituted to fix the intraabdominal pressure on 5 mmHg for 60 min. The antioxidants, vitamin E and NAC were given to rats 3 days before the operation and were applied for 30 days; amifostine was applied 30 min before the operation until after for 7 days. After abdominal desufflation, over biopsies were made on the 13th min, 24th h, and 7th and 30th days. By using of transmission electron microscopy, the damage on cells and organels were assessed and graded. RESULTS: In ovarian surface epithelium, the apical surface specializations were affected in all groups except Vit E group:The microvilli were irregular and coarse and had disappeared in some places. Some cells were separated from the epithelium. In addition, mitochondria degeneration was observed in all group except Vit E. CONCLUSIONS: In the early period of laparoscopy, reversible cellular damage occurs and this damage can be prevented by vitamin E.

Protective role of simvastatin on lung damage caused by burn and cotton smoke inhalation in rats.

BACKGROUND: Smoke inhalation injury is a major comorbid factor in patients with thermal injury and occurs in about 30% of patients with major burns. In addition, inhalation injury reportedly accounts for 20%-84% of the mortality in burned individuals and is associated with higher mortality rates for every age and burn size category. The aim of the present study was to investigate the effects of simvastatin on lung damage with burn and cotton smoke inhalation. METHODS: Wistar rats were randomly assigned to three groups: saline treated control group, via an orogastric route (group 1, n = 6), burn (30%) and cotton smoke inhalated group (group 2, n = 6), and simvastatin treated (25 mg/kg/d, via an orogastric route) burn (30%) and cotton smoke inhalated group (group 3, n = 6). Rats were sacrificed at 48 h of the treatments and the trachea and lungs were removed completely. Tissue samples were taken for histopathologic, immunohistopathologic, and biochemical analyses. Univariate analysis of variance coupled with Duncan's post-hoc test was performed for statistical evaluation. RESULTS: Lung parenchymal and tracheoepithelial damage was confirmed in group 2 by histopathologic examination. Lung malonedialdehyde (MDA) levels were significantly decreased (P < 0.001), while glutathione (GSH) concentration did not alter in group 2 compared with group 1. Also, immunopathologic data revealed that epithelial iNOS level was elevated, while no modulation was detected in the level of myeloperoxidase (MPO). Simvastatin administration resulted in decreasing the lung parenchymal and tracheoepithelial damage. Tissue MDA levels were decreased significantly (P < 0.001), whereas GSH concentrations were elevated in group 3 compared with group 1 and group 2 (P < 0.001). Simvastatin treatment caused a decrease in epithelial iNOS levels, while MPO levels were not modulated. In addition, simvastatin significantly reduced pulmonary apoptosis in lung injury. CONCLUSIONS: Our results have indicated that simvastatin administration seems to play beneficial role in lung injury of rats promoted by combined burn and smoke inhalation. Thus, simvastatin may represent a potential approach to prevent smoke inhalation-associated lung dysfunction. However, the significant decrease in basal oxidant production may cause impairment in cellular signalling processes.

Electron microscopic evaluation of the secretory mechanisms of renin from juxtaglomerular cells / Evaluación con microscopía electrónica de los mecanismos secretorios de renina desde las células juxtaglomerulares

Although the structure and the functions of juxtaglomerular cells (JG) have been well defined, there is still a controversy about the secretory mechanisms of renin from these cells. It has been assumed that exocytosis is the main secretory mechanism in these cells in many studies, while others suggest that secretion occurs in a quite different way in these cells. There are several studies suggesting that diacrine secretion, which is very difficult to visualize, might be the other mechanism for secretion of renin. This study is an attempt to find the answers of these questions by identifying the fine structural features of the secretory granules in juxtaglomerular cells. Cyclosporin A (CyA) has been used in the current experimental study since it has already been reported that this drug increases the number of JG cells and stimulates secretion of Renin. Twelve female Sprague-Dawley rats had daily intraperitoneal injections of CyA for ten weeks. Tissue specimens from the kidneys of these animals were examined by electron microscopy. Fine structural characteristics of the secretory granules of juxtaglomerular cells have been examined. Considerable amount of granules, which goes to the exocytotic process, have been observed. Additionally, several cells, which their granules had been secreting their contents in a different way, were found. This was interpreted as the secretion type of diacrine secretion. In conclusion, this in vivo study presents morphologic evidences demonstrating that both exocytosis and diacrine secretion might occur in JG cells. We also had a chance to observe secretory granule probably exhibiting "diacrine secretion", which is very difficult to visualize, at electron microscope level for the first time. This report also provides morphologic proof which shows that these two distinct secretory mechanisms might occur simultaneously in the same juxtaglomerular cell.

Aunque la estructura y las funciones de las células yuxtaglomerulares (JG) han sido bien definidas, todavía existe controversia acerca de los mecanismos de secreción de renina en estas células. Se ha supuesto, en muchos estudios, que la exocitosis es el principal mecanismo de secreción de estas células, mientras que otros autores sugieren que la secreción se produce de una manera muy diferente en estas células. Hay varios estudios que plantean que la secreción diacrina, que es muy difícil de visualizar, podría ser otro mecanismo para la secreción de renina. Este estudio tiene como objetivo encontrar las respuestas a estas interrogantes mediante la identificación de las características estructurales de la secreción de gránulos en las células yuxtaglomerulares. Ciclosporina A (CyA) se ha utilizado en el estudio experimental actual, debido a que se ha informado que este medicamento aumenta el número de células JG y estimula la secreción de renina. Doce ratas hembras Sprague-Dawley fueron diariamente inyectadas por vía intraperitoneal, con CyA durante diez semanas. Las muestras de tejido renal de estos animales fueron examinadas a través de microscopía electrónica. Detalladas características estructurales han sido examinadas en los gránulos secretores de las células yuxtaglomerulares. Se ha observado una cantidad considerable de gránulos, que va con el proceso de exocitosis. Además, se encontaron células que habían secretado el contenido de sus gránulos de manera diferente. Esto fue interpretado como secreción de tipo diacrina. En conclusión, este estudio in vivo presenta evidencias morfológicas que demuestran que tanto la exocitosis y la secreción diacrina podría ocurrir en células JG. También tuvimos la oportunidad de observar probables gránulos secretores, que mostrarían "la secreción diacrina", que es muy difícil de visualizar, a nivel de microscopía electrónica. Este informe también proporciona la prueba morfológica que demuestra que estos dos mecanismos...

Induction of apoptosis of rabbit corneal endothelial cells by preservative-free lidocaine hydrochloride 2%, ropivacaine 1%, or levobupivacaine 0.75%.

PURPOSE: To determine and compare the amount of apoptosis and changes in rabbit corneal endothelial cell morphology after intracameral administration of different anesthetic agents. SETTING: Department of Ophthalmology, Baskent University Medical Faculty, Ankara, Turkey. METHODS: Right eyes of 64 Vienna white rabbits were injected intracamerally with preservative-free lidocaine hydrochloride 2%, ropivacaine 1%, levobupivacaine 0.75%, or fortified balanced salt solution (BSS Plus) (control). Animals were humanely killed 1 day or 7 days later. Terminal deoxynucleotidyl transferase deoxy-UTP-nick end labeling was used to detect apoptosis. Corneal endothelial cells and apoptotic cells were counted by light microscopy. The morphologic appearance was determined by transmission electron microscopy (TEM). RESULTS: Apoptotic cell density was high in the anesthetic groups on day 1 (P<.01); there was no significant difference between groups at 7 days. Apoptotic cell density declined significantly between 1 day and 7 days in the anesthetic groups (P<.05) but not in the control group. There was no difference in endothelial cell density between the 4 groups at 1 or 7 days. All anesthetic groups showed degenerative changes on TEM, with the least change in the preservative-free lidocaine hydrochloride 2% group. CONCLUSIONS: Intracameral injections of preservative-free lidocaine, ropivacaine, and levobupivacaine induced significantly more apoptotic endothelial cell loss than BSS Plus and led to morphologic changes in the corneal endothelial cells in the early period. This effect was temporary, with recovery by 7 days. Considering the limited proliferative capacity in human eyes, the induced apoptosis might result in the permanent cell loss and enlargement in human corneal endothelium.

Correlation between proteinuria level and renal morphology with special reference to electron microscopy in kidney donors.

The aims of this study were to evaluate whether there is a correlation between protein level in urine and renal morphology in kidney transplant donors, as well as to detect the role of electron microscopy. For this purpose, kidney biopsies of 10 donors with urine protein levels were evaluated. Seven patients were female and three were male. Two had physiologic proteinuria (< 150 mg/24h), four had non-significant proteinuria (150-300 mg/24h), and three had significant (> 300 mg/24h) proteinuria. Serum creatinine levels were in normal ranges in all patients except for one who had a slight increase (1.76 mg/dL). Seven cases were reported to have normal or nonspecific light microscopic findings. Two of those seven cases had physiologic proteinuria, three had non-significant proteinuria, and two had significant proteinuria. One case had IgA nephropathy with significant proteinuria. One donor had early stage focal segmental glomerulosclerosis with non-significant proteinuria, and one donor had focal interstitial fibrosis with normal urine protein level. There was no statistically significant difference between score means of ultrastructural morphology of the six patients with same patients' light microscopic results and score means of light microscopic results with urine protein levels of all patients. However, there was a significant difference between score means of ultrastructural morphology with urine protein levels of those six patients. In conclusion, urine protein levels and light microscopic findings did not always reflect the detailed morphology alone and together. Therefore, combining with electron microscopic examination could be more beneficial in relieving problems occurring in long-term prognoses.

The bactericidal and morphological effects of peroxynitrite on Helicobacter pylori.

Peroxynitrite (ONOO-) is correlated with the pathogenesis of Helicobacter pylori-induced peptic ulcer diseases. We aimed to investigate the time- and concentration-dependent bactericidal and morphological effects of ONOO- on H. pylori. Authentic ONOO- was synthesized as quenched-flow method. A stock culture of H. pylori NCTC 11637 was exposed to different concentrations of ONOO- (0.1-40 micromol/L) or decomposed ONOO- or fresh medium. Samples were taken at 0, 15, 30, 60, and 120 minutes, for the evaluation of viable bacteria and bacterial morphology with gram strain and transmission electron microscopy. Decomposed ONOO- showed no bactericidal activity against H. pylori. ONOO- application caused a decrease in the number of viable bacteria within the first 15 minutes. The significant conversion of H. pylori from spiral form to coccoid form was determined with 10 micromol/L of ONOO-, and higher concentrations caused lysis of the cells. Separation of cell wall, bleb formation, vacuolization, decrease of secretory granules, and lysis of bacteria were the morphological effects of ONOO- on H. pylori. Because the morphology of the bacteria is one of the important factors in virulence; peroxynitrite-related morphological effects might have an impact in the progress of the H. pylori-induced peptic ulcer diseases.

Evaluation of ocular surface changes in a rabbit dry eye model using a modified impression cytology technique.

PURPOSE: To evaluate the ocular surface changes in a rabbit dry eye model by using a modified impression cytology technique. METHODS: Nitrocellulose filter paper with a pore diameter of 0.45 microm was used to collect the specimens from 12 rabbits that were injected with atropine every day for 3 days. Filter papers were kept in distilled water overnight and then dried to increase cell pickup. Samples were stained with periodic acid-Schiff. The mean temporal and superior bulbar conjunctival goblet cell densities were counted. The data were compared with transmission (ocular surface) and scanning electron microscopic (filter paper) examination of the ocular surface. RESULTS: In the acute stage of atropine injection, there was not a major change in the goblet cell count. Although the goblet cell distribution was variable over the ocular surface, the average cell density was 55.4+/-22 in the superior quadrant and 69.2+/-9 in the temporal quadrant. In the 3-day atropine-injection group, there was a marked decrease in goblet cells, and there was mucin accumulation rather than accumulation of the goblet cells. No morphologic differences could be observed with scanning electron microscopy between the regular nitrocellulose filter paper and the paper kept in distilled water. CONCLUSIONS: The findings indicate that keeping the filter paper in distilled water and then drying it improves cell pickup and ocular surface evaluation in rabbits.

Ultrastructural examination of glomerular and tubular changes in renal allografts with acute rejection.

Acute rejection is the most important threat to transplanted kidneys in the early phase after transplantation. With the advances in renal transplant surgery and immunosuppressive therapies, one-year graft survival rates reached 90%, but long-term graft survival did not improve to a similar degree. To prevent acute rejection more effectively and decrease the risk of chronic nephropathy development, the pathogenesis and effects of acute rejection on renal grafts should be further explored. This study aimed to examine the glomerular and tubular changes ultrastructurally. Tissues were obtained from 11 renal allografts with acute rejection, fixed in 1% Osmium tetra oxide embedded in Epon. The changes in glomerular basement membrane, podocyte, mesangium, and proximal tubules were examined by electron microscope. Tubular changes such as tubular basement membrane multi-lamellation, MN and PMN cells in peritubular capillaries, tubular vacuolization, mitochondrial changes (increase in number, alterations in cristae organization, or cristae effacement), and infiltration of tubular epithelium by MN cells (mainly lymphocytes) were found statistically significant (p < 0.01) when compared to those of control group. Some forms of endothelial injury (swelling of endothelial cells or fenestrae loss) were also statistically significant (p < 0.01). Acute rejection is an important predictor of long-term graft survival, and there may be no clinical clue to make diagnosis easier. Therefore ultrastructural changes may help solve this problem together with molecular studies.

The ultrastructural alterations in rat corneas with experimentally-induced diabetes mellitus.

OBJECTIVE: To examine the ultrastructural changes of rat corneas in streptozotocin (STZ) induced diabetes mellitus and the follow-up insulin treatment. METHODS: Sprague-Dawley type rats was used for experimental procedures during the period from January to April 2003 at Baskent University, Ankara, Turkey. Rats were studied in 4 groups; group 1: controls, group 2: sham controls (single dose IV sodium citrate), group 3: STZ-induced diabetes mellitus (single dose 45 mg/kg STZ intravenously), group 4: diabetes mellitus + insulin treatment (8 U/day). RESULTS: We observed degenerative changes in the epithelial layer, stromal keratocytes and endothelial cells in diabetic group. In contrast, the corneal layers have revealed positive alterations in the insulin-treated group. The statistical analyses showed significant narrowing in the epithelial layer in the diabetic group (p=0.002), whereas thickening was observed in the epithelial basement membrane and Descemet's membrane (p=0.002). CONCLUSION: It was determined that diabetes mellitus causes degenerative changes in cornea, which are positively influenced by short-term insulin treatment.

Effects of heparin on bacterial translocation and gut epithelial apoptosis after burn injury in the rat: dose-dependent inhibition of the complement cascade.

This study investigated levels of complement inhibition, apoptosis of gut epithelium, and bacterial translocation (BT) associated with different doses of heparin in rats with severe burns. After burn injury, the animals in Groups 1, 2, 3, and 4 received intravenous tail-vein bolus heparin doses of 150, 300, 600, and 1200 U/kg, respectively. Group 5 received no heparin after burn injury. Group 6 served as control group. According to the results, Group 2 had the highest rate of positive staining for C3, and Group 4 had the lowest rate. There were significant differences between these two groups with respect to distribution of immunoflouresein scores for C3 (p=0.01). Group 5 had the highest mean TUNEL index of all the groups (258/10) (p=0.01). On electron microscopy, the connective tissue cells in the ileal submucosa from Groups 4 and 5 showed more significant apoptotic changes than the corresponding cells in the other groups. The total BT values in Group 4 (129 x 10(4) CFU) and Group 5 (100 x 10(4) CFU) were both significantly higher than those in the other groups (p=0.01). Group 1 had the lowest total BT value (6.1 x 10(2) CFU) (p=0.001). In summary, our results confirm that heparin administration after significant burn injury in rats can reduce BT, and that the effect is related to dose. The findings also indicate that levels of BT after burn injury increase in parallel with the extent of gut epithelial cell apoptosis.

Apoptosis in cyclosporin A-induced gingival overgrowth: a histological study.

BACKGROUND: Cyclosporin A (CsA) is known to induce gingival overgrowth. Apoptosis plays a critical role in the regulation of inflammation and the host immune response. The aim of this study was to investigate apoptosis in CsA-induced gingival enlargement using electron microscopy examination of keratinocytes. METHODS: Gingiva specimens were collected from 12 CsA-treated renal transplant patients with gingival overgrowth and eight healthy controls with gingivitis. Clinical findings (probing depth, gingival index, and plaque index) were compared in the two groups. Histological and ultrastructural features of the specimens were also compared, and extent of keratinocyte apoptosis was scored on a three-tier scale: 0 = no apoptotic cells; 1 = one or two apoptotic cells; 2 = more than two cells. RESULTS: There were no significant differences between groups with respect to gingiva-related clinical findings or extent of keratinocyte apoptosis. CONCLUSIONS: The results indicate that the extent of keratinocyte apoptosis in the gingiva of kidney recipients with CsA-induced gingival overgrowth is similar to that observed in inflamed gingiva of healthy individuals. Further studies on apoptosis of different cell types in the presence of CsA should clarify this agent's role in the pathogenesis of drug-induced gingival enlargement.

Electron microscopy findings in the nasal mucosa of a patient with stenosis of the nasal vestibule.

The nasal mucosa humidifies, warms and filters inspired air before it passes to the lower respiratory tract. In order to maintain the physiological activity of the respiratory epithelium, a certain amount of airflow is required. This report describes electron microscopy findings in the nasal mucosa of a patient who had decreased airflow through the nose due to stenosis of the nasal vestibule. Electron microscopic examination of the nasal mucosa revealed stratified squamous epithelium composed of markedly degenerated cells. The findings of abnormal mucosal structure highlight another negative consequence of nasal obstruction in addition to abnormal physiological function of the nose. The negative impact of diminished airflow on the nasal mucosa should be considered in any case where the patient has a condition that can lead to partial or total loss of airflow through the nose.

The effect of melatonin treatment on oxidative and nitrosative stress in rats with thioacetamide-induced hepatic damage.

BACKGROUND: : The following study aimed to clarify the importance of arginase and NOS activities in thioacetamide-induced hepatic damage and to evaluate the underlying mechanism of proposed protection provided by melatonin, using commonly applied therapeutic dose. METHODS: : Rats were randomly assigned to four groups (n=5): control, melatonin (10mg/kg i.p.), thioacetamide (200mg/kg i.p., two doses with a 24h interval) and thioacetamide+three doses of melatonin (10mg/kg i.p., prior- and post-treatment with a 24h interval before thioacetamide administrations) treated groups. RESULTS: : Thioacetamide administration caused hepatic damage creating oxidative and nitrosative stress accompanying perivenous necrosis and eosinophil infiltration. The significant elevation of total nitrite level in livers of thioacetamide treated groups reflected the activation of inducible nitric oxide synthase activity. The decrease in arginase activity indicated hepatic damage. Non-altered specific activity of arginase in the livers of thioacetamide treated groups did not overcome the elevation of NO production. Melatonin treatment did not modulate the levels/activities significantly. CONCLUSIONS: : Our results have indicated that nitrosative stress seems to be essentially critical in thioacetamide-induced hepatic failure in rats. Possible regulatory effect of arginase on NO production and applied dose of melatonin could not prevent hepatic damage.