A Lipotoxic Medium Decreases the Number of Lipid Droplets in ß Cells: One Possible Explanation of the ß-Cell Failure in Patients With Hyperlipidemia Receiving Tacrolimus.

OBJECTIVES: Dyslipidemia is a risk factor for post- transplant diabetes mellitus, especially in patients who are taking tacrolimus. Although lipotoxicity of dyslipidemia leads to ß-cell failure, the handling of lipids by ß cells is a mystery in molecular endocrinology. Likewise, lipid droplet homeostasis is appreciated as a key component of lipid metabolism in cells like hepatocytes, but its role in ß cells remains to be elucidated. MATERIALS AND METHODS: To evaluate the morphologic changes in ß cells with special focus on lipid droplets, we evaluated electron micrographs under metabolic stress conditions of glucotoxicity, lipotoxicity, and glucolipotoxicity in isolated rat insulinoma INS-1E ß cells. Cells were treated with palmitic acid (0.5 mM), glucose (33 mM), or both for 16 hours, after which morphologic changes were observed with an electron microscope. RESULTS: Many lipid droplets were observed in the cytoplasm of healthy ß cells in the control group (no treatment). Lipid droplets were also visible in the cytosol, and the cytoplasm was rich in organelles and insulin vesicles under high glucose stimulation. However, after treatment with palmitic acid, almost no lipid droplets were observed. Endocrine vesicles were also depleted, with severe morphologic disruption of other organelles. Under glucolipotoxic conditions, ß cells showed a decreased number of lipid droplets and insulin vesicles compared with controls. CONCLUSIONS: Lipid droplet dynamics seemed important in the homeostasis of ß-cell metabolism. In this preliminary study, healthy ß cells appeared rich in lipid droplets under normal conditions. However, lipotoxicity depleted and glucolipotoxicity decreased the number of lipid droplets in ß cells. Because dyslipidemia causing lipotoxicity is one of the most frequent metabolic problems in transplant patients and increases risk of posttransplant diabetes mellitus, understanding the mystery of lipid droplets in ß cells and the pathophysiology of diabetes in transplant patients is important, especially for those taking tacrolimus.

Implications for thymus growth in childhood: histogenesis of cortex and medulla.

The increase in autoimmune diseases in recent years has drawn attention back to the thymus, with new approaches to improve and/or restore immune function being investigated. As the primary lymphoid organ responsible for functional T cell development, studies on the pre-/post-natal development of this organ and T lymphocytes in human and other species are of special interest. During our screening studies we observed structures that had not been described or mentioned previously, and named them "epitheliostromal sheaths". Associated with these unique structures were also small attached lobules (possibly reflecting the maturational stages of thymic lobules), which the authors consider as markers of histogenesis and the growth of the organ during early childhood; these findings are thus presented to researchers in this field. Approximately 1000 sections prepared from infantile thymic tissues of partial biopsy specimens were immunostained and examined. Specimens were taken from ten patients (with informed consent) in the age range of 4-9 years who underwent surgery due to congenital cardiovascular anomalies but were otherwise normal. Digital images of interest were captured to describe them in detail. Determining the immunophenotype of the compartments in these newly developing lobules assisted us greatly in defining compartments and their growth order. In summary, our findings suggest a niche-based thymus growth mechanism during childhood. We presented our findings, hoping to provide additional insight to researchers aiming to restore thymus function in adulthood and improve its immunological functions.

Which type of conditioning method protects the spinal cord from the ischemia-reperfusion injury in 24 hours?

OBJECTIVE: This study was designed to test the effects of different types of preconditioning and postconditioning methods on spinal cord protection following aortic clamping. METHODS: The animals (rabbits) were divided into sham-operated, ischemic preconditioning, remote ischemic preconditioning, simultaneous aortic and ischemic remote preconditioning, and ischemic postconditioning groups. After neurological evaluations, ultrastructural analysis and immunohistochemical staining for caspase-3 were evaluated after 24 h following ischemia. RESULTS: The neurological outcomes of the remote ischemic preconditioning (4.2 ± 0.4) and ischemic postconditioning (4.6 ± 0.8) groups were significantly improved when compared with the ischemia group (2.2 ± 04). The immunohistochemical analysis revealed that the lowest percentage of apoptosis was in-group ischemic preconditioning at 12.5 ± 30.6%. In the comparison of intracellular edema in an ultrastructural analysis, the ischemic preconditioning and ischemic postconditioning groups had significantly lower values than the ischemia group. CONCLUSION: The conditioning methods attenuate ischemia-reperfusion injury for spinal cord injury. Ischemic and remote preconditioning and also postconditioning methods are simple to perform and inexpensive.

Effects of intra-articular administration of autologous bone marrow aspirate on healing of full-thickness meniscal tear: an experimental study on sheep.

OBJECTIVE: The aim of this study was to evaluate the effects of bone marrow-derived mesenchymal stem cell and bone marrow elements on the healing of meniscal tears. METHODS: This study was performed on twelve, 2-year-old male Tahirova sheep. In each subject, one knee was used for experiment purposes and the other knee was used as a control. After creating a longitudinal full-thickness tear in the red-white zone of the medial meniscus, aspirated autologous bone marrow material was injected into the tear site in the experiment group. The control group received no intervention for secondary healing. RESULTS: In the macroscopic evaluation of meniscus, a bridging reparation tissue and adhesion were observed between the rims of the tear in the experiment group. There was no statistical difference in collagen fibril formation between the groups (p=0.16). There was significantly more neovascularization in the experiment group than the control group (p=0.003). The cell count was also a significantly higher in the experiment group (p=0.004) and formation of cartilage plaques was more frequent in the experiment group (p=0.016). There was no evidence suggesting intrinsic repair in the meniscus of control group by light and electron microscopy. CONCLUSION: An injection of bone marrow into the meniscus tear site improves healing in a meniscal tear model as demonstrated by both light and electron microscopic findings.

Rosuvastatin induces apoptosis in cultured human papillary thyroid cancer cells.

Statins show antiproliferative activity in various cancer cells. The aim of this study was to evaluate the effects of rosuvastatin treatment on papillary thyroid carcinoma. The papillary thyroid carcinoma (B-CPAP) and normal (Nthy-ori 3-1) thyroid cell lines were treated with rosuvastatin at 12.5, 18.5, 25, 50, 100, and 200 µM concentrations. After 48 and 72 h of rosuvastatin treatment, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, Ki-67 immunolabeling, FACS analysis, electron microscopy, caspase-3, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) analysis were performed. Decreased cell viability and G1 phase arrest were detected in papillary thyroid cell line treated with rosuvastatin. Positive immunoreactivity of Ki-67 and dose-dependent increase in S phase on Nthy-ori 3-1 cells were also detected. B-CPAP cells showed intense vacuolisation and autophagosomes with low concentrations and 48 h incubations, while Nthy-ori 3-1 cells showed these changes at higher concentrations. A decrease in the percentage of cells showing autophagy was determined with increasing concentrations of rosuvastatin in B-CPAP cells. Rosuvastatin treatment also caused a dose- and time-dependent increase in caspase-3 activity and apoptotic index by TUNEL assay in B-CPAP cells compared with the Nthy-ori 3-1 cells. Apoptotic cells with nuclear condensation and fragmentation were observed in B-CPAP cell line. Rosuvastatin induced autophagic changes in B-CPAP papillary thyroid cancer cells in lower doses and caused a shift from autophagy to apoptosis. Rosuvastatin may be an alternative treatment for refractory papillary thyroid cancer. Further in vivo studies are necessary to clarify the effects of rosuvastatin in papillary thyroid carcinoma and the clinical implications of rosuvastatin treatment.

Fibronectin promotes the phorbol 12-myristate 13-acetate-induced macrophage differentiation in myeloid leukemia cells.

The extracellular matrix plays a critical role in macrophage maturation. In this study, the HL60 cell line was used as a model of leukemic myeloid cell differentiation. We assessed the ability of HL60 cells cultured on fibronectin substratum prior to phorbol 12-myristate 13-acetate (PMA) induction to differentiate into terminally differentiated macrophages. Beside their distinctive macrophage morphology, they expressed antigen receptors CD14, TLR2, TLR4 and CD68, and displayed enhanced phagocytic activity and production of reactive oxygen species. Expression of CD13, CD33, CD15 and alpha-naphthyl-acetate esterase was also maintained, however, differentiated HL60 cells were HLA-DR and CD1a negative. Here, we describe the enhanced capacity of fibronectin-adherent HL60 cells to differentiate into macrophages in response to PMA.

Effects of topotecan treatment on nasal, buccal, and lingual mucosa in the rabbit: light and transmission electron microscopic evaluation.

Anticancer agents may cause side effects and some of which may be dose dependant. It is important for clinicians to see the effects on tissues histopathologically. The aim of this study was to investigate the effects of topotecan (hycamtin), a topoisomerase I inhibiting anticancer agent, on nasal, buccal, and lingual mucosa of rabbits. The study was carried out in two groups each consisting of 20 rabbits. Rabbits in group I received i.v. topotecan (0.5 mg/kg once daily) for 3 days. Rabbits in group II received i.v. topotecan (0.25 mg/kg once daily) for 3 days. In group I and II, biopsies from the nasal, buccal, and lingual mucosa were taken on the fourth (1 day after the 3-day topotecan treatment) and 15th day (12 days after the 3-day topotecan treatment). Light and transmission electron microscopic (TEM) observations have shown that nasal mucosa was not affected by topotecan administration. Topotecan treatment resulted in the formation of some ulcerative lesions in the lingual mucosa especially on the lower surface of the tongue. On the dorsal surface, the epithelium showed highly edematous and degenerating cells and separations in the stratum granulosum. In the buccal mucosa, effects were similar. In lingual and buccal mucosa, healing was observed on the 15th day. The oral (lingual and buccal) mucosal side effects of topotecan were observed as reversible and not dose dependent. It was concluded that these side effects are not severe, and topotecan may be used safely in cancer treatment.

The effect of subcutaneously injected nicotine on achilles tendon healing in rabbits.

The objective of this study was to evaluate the effect of subcutaneously injected nicotine on transversely transected and sutured achilles tendon healing in an experimental rabbit model. Adult New Zealand rabbits (n=22) weighting 3,000-3,500 g were used in this experimental study. Rabbits were randomly divided into two groups. Achilles tendon was transversely incised and repaired in all animals. In the experiment group subcutaneous injection of Nicotine tartrate 3 mg/kg/day was done. In the control group Serum physiologic injection was done at the same dosage. The injections were made three times a day in equal dosages. Nicotine and SF injections were made until the end of the 8-week, and then all animals were euthanized. Both light microscopic and electron microscopic evaluations were made on 14 animals. In N group light microscopic evaluation showed a visible gap in repair site. The total tendon score represented in N group was less than in SF group. The statistical analysis of the groups was significantly different for total tendon scores (P=0.002). Beside this electron microscopic examination showed inactive and degenerated fibroblasts and irregular collagen fibrils around them as well as collagen synthesis interruption in N group. Biomechanical evaluation was made on eight animals. The average tensile strength values in Group N (139.47+/-44.55 N) were significantly lower than those in Group SF (265.9+/-39.01 N) (z=2.309, P=0.029). Nicotine is the major chemical component common to all cigarettes and previously has been shown to affect wound and fracture healing adversely. The results of this study show that nicotine impairs achilles tendon healing after a surgical repair.

Evaluation of the toxic effects of cypermethrin inhalation on the frog heart.

Cypermethrin is widely used as an insecticide on animals and in agriculture, the home, and the garden. The effect of inhaled cypermethrin on the cardiac mechanics, electrophysiology, and ultrastructure in frogs was investigated in this study. Four groups received 100 microL of cypermethrin via inhalation for different exposure times, and one group was used as a control. Electrical and mechanical activities of the heart were recorded, and heart samples were examined at light and transmission electron microscopic levels for all groups. The atrial and ventricular contractile forces on the mechanogram, the amplitude of the P wave and the QRS complex on electrocardiogram, and the heart rate were significantly decreased in cypermethrin-inhalated frogs. The total duration of contraction was prolonged in the study groups. Ultrastructurally, dilatation in smooth endoplasmic reticulum cisterns, a decrease in the number of mitochondria, disorganization in the myofibrils of myocytes, and necrotic changes in endothelial cells were observed. These results suggest that cypermethrin has cardiotoxic effects that increase with exposure time.

Antigenic profile of human thymus in concurrence with "Clusters of Thymic Epithelial Staining" classification.

We examined the expression of various CD coded or not yet defined antigens in human thymus samples using indirect immunoperoxidase and immunoflourescent techniques. Data obtained are presented in concurrence with Clusters of Thymic Epithelial Staining (CTES) classification for various monoclonal antibodies recognizing CD antigens (CD1, CD1a, CD6, CD9, CD14, CD16, CD29, CD30, CD32, CD44, CD45RB, CD47, CD48, CD49a, CD49b, CD49c, CD49d, CD49e, CD49f, CD51, CD53, CD54, CD56, CD57, CD63, CD85, CD95, CD98, CD102, CD103, CD106, CD109, CD146, CD147, CD148, CD151, CD152, CD158a, CD158b, CD164, CD165, CD166) and for monoclonal antibodies 1B10, 5G7, A4, BD46, BLTZ, HP1C5, IND.64, M72, WU947 whose specifities are not yet defined. Some of the mAbs such as CD49f, IND.64 and BD46 are detected as good markers for specific cell types or compartments. Significance of the presence of these antigens on thymic epithelial cells at certain locations is briefly discussed.

Effects of electrohydraulic extracorporeal shock wave lithotripsy on submandibular gland in the rat: electron microscopic evaluation.

OBJECTIVES: Extracorporeal shockwave lithotripsy (ESWL) has been applied in sialolithiasis as a new treatment modality. The aim of this experimental study is to investigate the local effects of electrohydraulic ESWL applied to the right submandibular gland of the rats. METHODS: This prospective study was conveyed in four groups; groups I, II, III and IV; each group consisting of 20, 20, 18 and 9 rats, respectively, with a randomized distribution. Groups I, II, III and IV received 250, 500, 1000 and 2000 shock waves at 14-16 kV (average 15.1 kV), respectively, to the right submandibular glands on the 0th day. In groups I, II, III, right submandibular glands of the rats were removed on the 0th, 1st, 7th and 15th days; in group IV, this procedure could be managed only on the 0th and 7th days. Light and electron microscopic evaluation were assessed. Using the light microscopic changes, severity of damage score of the glands (SDS) was found. Statistical analysis was done using SDSs. RESULTS: Light and electron microscopic observations have shown that the damage produced by the shock waves were confined to focal areas in the acinar cells (AC), granulated convoluted tubule (GCT) cells and blood vessels at all doses applied. Vacuolization in the cytoplasms of the AC and GCT cells, disintegration of membranes, alteration in the cytoplasmic organization, swelling of the mitochondria and loss of the features were observed on electron microscopy. Increase in the secretion rate; stasis and dilatation in the blood vessels; blebbing and loss of features in the cytoplasm of the endothelial cells were observed. According to the result of the statistical analysis using SDSs; at 250 shock wave dose, a statistically significant difference between the SDSs of the days (0th, 1st, 7th and 15th) was found (P<0.05). The SDS on the 0th day was found to have the lowest value among the other days. And also a statistically significant difference was found on the 0th day between the SDSs at doses of 250, 500, 1000 and 2000 shock waves (P<0.05). The SDS at 250 and 500 shock waves was found to have the lower value than the SDS at the 2000 shock wave. It was observed that produced damage was less prominent by small doses (250, 500 doses) initially (0th day). Electrohydraulic ESWL caused a "patchy type" generalized pathology on submandibular glands of the rats and damaged focal areas were widespread all through the gland from the 1st day on. CONCLUSION: Formation of the damage was concluded to be related to the direct effect of the shock waves rather than the dose used. Electrohydraulic lithotripters are not suitable for sialolithiasis because of the focus problems, local tissue damage and the risk of the damage to the adjacent structures.