Ultrastructural evaluation of urine alkalinization versus hydration on colistin-induced nephrotoxicity.

OBJECTIVES: Colistin is a vital antibiotic used in multidrug-resistant infections. Its most important side effect is nephrotoxicity. Colistin is a weak acid. This study aims to evaluate whether urine alkalinization is protective in the nephrotoxicity of colistin. METHODS: Twenty-eight male Sprague-Dawley rats were divided into groups. Group I (n = 4) was injected with intramuscular distilled water twice a day for 7 days. Group II (n = 8) was injected with 750,000 IU/kg/day colistin for 7 days. Group III (n = 8) was injected with the same dose of colistin after their urinary pH was ≥7 through the addition of bicarbonate in their drinking water. Group IV (n = 8) was injected with the same dose of colistin after their urine density fell below 1010 through the addition of NaCl molds in their food and 12.6 mg/L NaCl in their drinking water. RESULTS: According to tubular degenerations (scored 0-5), group I scored 0, group II scored 4.25, group III scored 2, and group IV scored 1.5. In groups III and IV, protection was achieved (p = 0.001). The bicarbonate group was not superior to the NaCl group (p = 0.789). In transmission electron microscopy, group III had more microvilli integrity and autophagic vacuoles compared to group IV. Group IV had mitochondrial swelling and cristae lysis. A lower urine density was related to lower tubular scores (p = 0.001). CONCLUSIONS: Colistin was highly nephrotoxic without protection. Light microscopy findings revealed that urinary alkalinization and NaCl hydration were similarly protective. Urine alkalinization further prevents ultrastructural changes as revealed by electron microscopy.

Histopathology of ipsilateral and contralateral ovaries and plasma interleukin 6 levels after unilateral ovarian torsion.

OBJECTIVE: The aim of the present study was to evaluate the time-dependent histopathologic changes in both ovaries and to determine the time-dependent levels of plasma interleukin 6 (IL-6) after unilateral ovarian torsion. MATERIALS AND METHODS: An experimental animal study included 48 female Sprague-Dawley rats which were distributed to six groups: control group (Group 1), sham-operated control group (Group 2), and four unilateral ovarian torsion groups with torsion duration of three, six, 12, and 24 hours (Group 3, 4, 5, and 6, respectively). Histopathologic criteria (follicular degeneration, vascular congestion, hemorrhage, inflammatory cell infiltration, and total tissue damage score) were evaluated in both ovaries, and plasma IL-6 levels were measured. RESULTS: At 24 hours after torsion began, mean total tissue damage score was similar between ovaries that had torsion and contralateral ovaries. Mean plasma IL-6 level did not change during the 24 hours after torsion began (p = 0.584). CONCLUSIONS: In addition to ovaries that had torsion, histopathologic abnormalities also occurred in contralateral ovaries. These results suggest that contralateral ovaries are not quiescent after unilateral ovarian torsion. Plasma IL-6 levels did not change significantly during the 24 hours after ovarian torsion began, resulting in a limitation of its diagnostic use in the early course of the disease.

Ultrastructural analysis of granulosa cells of IVF patients.

OBJECTIVE: To compare the percentage and ultrastructure of normal and abnormal granulosa cells and their effect on fertilization and pregnancy rate between gonadotropin releasing hormone (GnRH) agonist and antagonist treatment. MATERIALS AND METHODS: In this study, granulosa cells obtained from 22 women undergoing in vitro fertilization (IVF) treatment due to unexplained infertility with either with GnRH agonist (n = 11) or GnRH antagonist (n = 11) were evaluated by light and electron microscopy. RESULTS: GnRH agonist and antagonist therapy was found to have no effect in terms of abnormal granulosa cell percentage (0.0679 ± 0.08977 vs 0.0481 ± 0.05164; p > 0.05), fertilization [85 (45-90) vs 75 (64-93)] and pregnancy rate (37% vs 46%). Light microscopic observations showed similar features of normal cells of agonist and antagonist-treated cells. Ultrastructural evaluation also revealed that there was no difference between cells of two treatment groups. CONCLUSION: Both GnRH agonist and antagonist treatment for ovarian stimulation may have similar effects on granulosa cells at the morphological and ultrastructural level, as well as on fertilization and pregnancy rates.

The effect of radiofrequency radiation generated by a Global System for Mobile Communications source on cochlear development in a rat model.

OBJECTIVE: This study aimed to determine the effect of radiofrequency radiation generated by 900 and 1800 MHz Global System for Mobile Communications sources on cochlear development in the rat model. METHODS: Eight pregnant albino Wistar rats were divided into three groups: control, 900 MHz and 1800 MHz. The latter two groups of pregnant rats were exposed to radiofrequency radiation for 1 hour per day starting on the 12th day of pregnancy until delivery. The rats in the control, 900 MHz and 1800 MHz groups gave birth to 24, 31 and 26 newborn rats respectively. Newborn rats in the 900 MHz and 1800 MHz groups were exposed to radiofrequency radiation for 1 hour per day for 21 days after delivery. Hearing evaluations of newborn rats were carried out using distortion product otoacoustic emissions testing. Eight newborn rats were randomly selected from each group for electron microscopic evaluation. RESULTS: Distortion product otoacoustic emission tests revealed no significant difference among the groups, but electron microscopic evaluation revealed significant differences among the groups with regard to the number of normal, apoptotic and necrotic cells. CONCLUSION: The findings indicated cellular structural damage in the cochlea caused by radiofrequency radiation exposure during cochlear development in the rat model.

Histologic changes caused by nonabsorbable sutures after ovarian suspension.

PURPOSE: To evaluate intraovarian histologic changes caused by polypropylene and silk sutures that commonly are used in ovarian suspension. MATERIALS AND METHODS: Twenty-four female rats were randomly allocated to three study groups: a sham group receiving no ovarian suspension; the other two groups that had right ovarian suspension with polypropylene and silk sutures. At 90 days after surgery, the histologic changes and ovarian weight reduction in the suspended ovaries and severity of pelvic adhesions were evaluated. RESULTS: There were no differences between study groups in focal inflammation, cystic structures, or vascularity. Adhesion severity and ovarian weight reduction in suspended ovaries and cysts around the suspended ovary were significantly greater in the silk than sham group. The frequency of hematoma within the suspended ovary was significantly greater in the polypropylene than sham group. CONCLUSIONS: Polypropylene suture caused less adhesion severity or ovarian weight reduction than silk suture. This suggests that polypropylene suture may be the better suture for ovarian suspension procedures.

The role of ascorbic acid on collagen structure and levels of serum interleukin-6 and tumour necrosis factor-alpha in experimental lathyrism.

Lathyrism is characterized by defective collagen synthesis due to inhibition of lysyl oxidase, an enzyme essential for interfibrillar cross-linking. The lathyritic agent beta-aminoproprionitrile (beta-APN) is considered an appropriate agent for studying connective tissue metabolism. We investigated the effects of ascorbic acid on collagen structure and serum cytokine levels in experimentally induced lathyrism. Forty Wistar rats weighing 200-300 g were used in the study: three test groups of 10 rats each (groups 2, 3 and 4) and 10 rats used as a control group (group 1). Experimental lathyrism was induced with daily subcutaneous injections of beta-APN in the test groups for 40 days. On the 40th day, skin biopsies were taken from the control group (group 1) and group 2, to evaluate the effect of beta-APN on dermal collagen. After the 40th day, 10 rats received ascorbic acid 100 mg/kg intraperitoneally daily for 15 days (group 3) and 10 rats (group 4) received no medication and served as a control for group 3. On the 55th day, skin biopsies were taken from groups 3 and 4. Serum concentrations of interleukin-6 and tumour necrosis factor-alpha were assessed in each group by enzyme-linked immunosorbent assay. Ultrastructural examination of the skin biopsies in group 1 revealed normal-appearing epidermal and dermal structures. Group 2 showed disorganization of the epidermis and collagen structure, and vacuolization of the endoplasmic reticulum in fibroblasts. In group 3, ultrastructural examination revealed significant improvement in the structure of dermal collagen after administration of ascorbic acid, whereas the changes in group 4 were unremarkable. Ascorbic acid administration significantly decreased the concentrations of serum cytokines in group 3 compared with group 2 (P < 0.001). Ascorbic acid administration significantly improved dermal collagen structure and serum cytokine levels in experimental lathyrism.

Myofibroblasts defined by electron microscopy suggest the dedifferentiation of smooth muscle within the sac walls associated with congenital inguinal hernia.

OBJECTIVE: To ascertain the presence of myofibroblasts in sacs associated with inguinal hernia in children, through an ultrastructural evaluation using electron microscopy. MATERIALS AND METHODS: Sacs were obtained from 10 boys and 10 girls (of similar age, approximately 45 months) with inguinal hernia and processed for electron microscopy. Thin sections were examined specifically for the presence of myofibroblasts. RESULTS: The ultrastructural evaluation showed myofibroblasts with classical electron microscopic features within all of the sacs, regardless of the gender of origin. CONCLUSION: The persistence of smooth muscle hinders the obliteration of the processus vaginalis; myofibroblasts are found in association with smooth muscle and thus such cells within the sac walls seem to originate from the smooth muscle, reflecting the dedifferentiation of smooth muscle. This dedifferentiated state may represent attempted apoptosis, which usually causes the disappearance of the smooth muscle and obliteration of the processus vaginalis after the descent of the testis into the scrotum.

Pulpal tissue in bilateral talon cusps of primary central incisors: report of a case.

Talon cusp is a tooth anomaly that affects both the primary and the permanent dentitions. However, the occurrence of this anomalous cusp is rather infrequent in the primary dentition. Only 7 cases of bilateral talon cusps affecting the primary teeth have been reported in the dental literature. This is a case report of bilateral talon cusps on primary maxillary central incisors whose histologic evaluation revealed the existence of pulpal tissue in the anomalous cusps.

Vasculogenesis in early human placental villi: an ultrastructural study.

In this study we examined the chorionic villi of 5 normal human placentas at 12-14 weeks of gestation ultrastructurally with regard to differentiation of the vascular components. The aim of the present report is to discuss the factors influencing vasculogenesis (in situ formation of blood vessels) at the ultrastructural level. Our observations have led us to think that the cytotrophoblast influences vasculogenesis in human chorionic villi. Mesenchymal-preendothelial cell groups were always found in very close association with the cytotrophoblast at the periphery of the villi, forming blood vessels. The cytotrophoblast probably attracts mesenchymal cells towards the margin of the villi by secreting vascular endothelial growth factor (VEGF). Once cells attach to the trophoblastic basement membrane they begin to differentiate into endothelial cells. This close structural relation between two cell types (cytotrophoblast and mesenchymal cells) may not be the only mechanism controlling vasculogenesis, but it seems to be one of the factors influencing the differentiation of mesenchymal cells into the endothelial cells of blood vessels in early human chorionic villi.

Cysts in human thymus: maturational forms of Hassal's corpuscles?

Presence of extracellular cystic cavities in the thymus of many vertebrates has long been known. Various forms of such structures in human thymus were observed and examined thoroughly on immunostained and serial semithin sections. We grouped these structures into five categories according to their most characteristic features. The lympho-epithelial content of the cysts clearly reflected the structural features and antigenic profile of thymic cortical parenchyma in both elongated and ovo-spherical cysts. Our findings suggest that the various types of cystic structures observed in human thymus may represent maturational stages of classical Hassal's corpuscles. Presence of cortical lympho-epithelial content and its gradual replacement with debris material also suggests a unique mechanism of thymocyte disposal.