M.O. Karayigit

The expressions of HSP70 and αB-crystallin in myocarditis associated with foot-and-mouth disease virus in lambs.

This study describes the expression of heat shock protein70 (HSP70) and alpha-basic-crystallin (α-BC) and their association with apoptosis and some related adaptor proteins in the pathogenesis of foot-and-mouth disease virus (FMDV)-induced myocarditis in lambs. HSP70 was generally overexpressed in the myocardial tissues and inflammatory cells of FMDV-induced myocarditis with differential accumulation and localization in same hearts when compared to non-foot-and-mouth disease control hearts. α-BC immunolabeling showed coarse aggregations in the Z line of the cardiomyocytes in FMDV-infected hearts in contrast to control hearts. Overall, the results of this study show that the anti-apoptotic proteins, HSP70 and α-BC, were overexpressed with increased apoptosis in FMDV-infected heart tissues. Both proteins failed to protect the cardiomyocytes from apoptosis as defense mechanisms to the FMDV during the infection, suggesting that the virus is able to increase apoptosis via both downregulation and/or upregulation of these anti-apoptotic proteins.

Immunohistochemical characterization of peroxisome proliferator-activated receptors in canine normal testis and testicular tumours.

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily. Recent studies have demonstrated that PPARs regulate lipid metabolism and are expressed in various cancers. The aim of the present study was to investigate the expression of PPAR-α, -β and -γ in normal canine testicular tissue and canine testicular tumours (CTTs). Expression of PPAR-α, -β and -γ was greater (P <0.05) than in normal testicular tissue. PPARs were therefore induced in CTTs and they may play a role in the biology of these tumours.

The effects of aging on the central nervous system steroid profiles and myelin basic protein in rats

The aim of this study was to investigate the effects of aging on the central nervous system steroid and myelin basic protein (MBP) profiles. Forty-seven male Sprague-Dawley rats (newborn, 1, 6, 12 and 24-monthsold) were studied. Tissues were obtained from the cerebellum and parietal, frontal, temporal cortex of the central nervous system of the rats for steroid extraction. The estradiol, progesteron, testosterone and dehydroepiandrosterone (DHEA) levels were measured by Enzyme Linked Immunosorbent Assay (ELISA). The average levels of estradiol (pg/g), progesteron (ng/g), DHEA (ng/g) and testosterone (ng/g) in the brain tissues were respectively 24.29, 4.59, 0.27, 0.92 in the newborn-rats; 4.18±1.10, 1.54±0.30, 0.28±0.01, 0.57±0.10 in the 1 month-old-rats; 11.02±1.10, 2.96±0.30, 0.27±0.01, 0.61±0.10 in the 6 month-old-rats; 15.80±1.10, 4.80±0.30, 0.28±0.10, 0.67±0.10 in the 12 monthold-rats; 20.07±1.10, 4.12±0.30, 0.28±0.01, 0.55±0.10 in the 24 month-old-rats. The myelin basic protein levels were determined by immunohistochemical staining and an elevation was observed in conjunction with the aging process. The results of the study indicate that the alterations in MBP, DHEA, progesterone, testosterone and estrodiol concentrations in the central nervous system of the rats during aging can be considered fundamental for future animal and human studies.

Nesidioblastosis in a Simmental Calf

A 2-day-old Simmental calf with arthrogryposis and astasia was subjected to necropsy examination. The calf was normoglycaemic and normoinsulinaemic. Microscopically, pancreatic tissue was hyperplastic with an irregular lobular arrangement of pancreatic islets. Newly-formed islet cells budded from intralobular or intercalated ducts (so-called ductulo-insular complexes) and there were prominent blood vessels with telangiectatic features surrounded by rows of cuboidal-columnar islet cells. The newly-formed islets expressed insulin antigen immunohistochemically. The lesion was diagnosed as nesidioblastosis, an uncommon abnormality previously associated with the double muscling trait in cattle.

Estrogen and Progesterone Synthesis with Cellular Response in a C57BL/6 Mouse Model of Cuprizone-Induced Demyelination

Background: Demyelination refers to the degradation or loss of myelin sheath. In demyelination model studies, it has been reported that demyelination is regressed by giving steroid hormones such as estrogen and progesterone. However, there are not many studies investigating the synthesis of these two hormones by the brain during demyelination and remyelination. Neurosteroids are steroid hormones synthesized by the brain independently from peripheral tissues. In this study, it was aimed to have knowledge about the synthesis of these two hormones by the brain in experimentally formed demyelination process in brains of C57BL/6 mice and their role in the cellular response formed in the region. Materials, Methods & Results: In the study, 36 C57BL/6 mice were used: 12 mice were fed normal diet for 12 weeks as control group (Group I); 12 of them were fed 0.2% cuprizone diet for 12 weeks (Group II) and 12 mice were fed normal diet for 4 weeks after feeding cuprizone diet for 8 weeks (Group III). At the end of the experiment, mice were perfused with 4% paraformaldehyde and brain tissues were blocked in paraffin. 6 μm-thick section was taken from each block. Sections were stained histologically with LFB staining and immunohistochemically with MBP staining in order to determine the demyelination in sections. All sections were also immunohistochemically stained with GFAP to detect astrocytes, with NG2 to detect young OPCs, with aromatase for estrogen synthesis and with 3βHSD antibodies for progesterone synthesis. At the end of the study, complete myelination was observed in group I, while severe demyelination was determined in group II as a result of blind evaluation of LFB and MBP staining by two pathologists. In group III, demyelination was found to be mild. In immunostaining with GFAP and NG2 antibodies, the number of GFAP and NG2 positive cells in Group II was found to be increased compared to the control group. The difference between these two groups was statistically significant (P < 0.01). In group III, the number of GFAP and NG2 positive cells were found to be increased compared to the control group; however, it was found to be lower than that in experimental group II (P < 0.01). In immunohistochemical staining with aromatase and 3βHSD antibody, there was no staining observed in the control groups. While an intense staining was observed in experimental group II, fewer glial staining was noticed in experimental group III when compared to the experimental group II. The difference between these two groups was found to be statistically significant (P ˂ 0.01). Discussion: Aromatase is an enzyme that converts testosterone into estrogen. On the other hand, 3βHSD is an enzyme that converts pregnenolone to progesterone. Expression of aromatase from tissues refers to the synthesis of estrogen and expression of 3βHSD refers to progesterone synthesis. In previous demyelination studies carried out with cuprizone, it has been reported that demyelination is regressed by giving estrogen and progesterone during demyelination. In the presented study, we observed that enzyme levels that catalyze the synthesis of estrogen and progesterone increased during demyelination. In the study, it was determined that estrogen and progesterone levels were increased in the region by enzymes released from the glial cells of the brain as a response to damage formed during demyelination. Interestingly, during the period in which cuprizone was excluded from the diet, it was observed that remyelination began to be formed again and that enzyme levels synthesizing these hormones started to decrease. These results suggested that estrogen and progesterone may be synthesized in the brain after a damage and may contribute to remyelination by initiating a number of cell to cell signaling steps.

Effect of Mitomycin C on bFGF, TGF-β1, KGF-1 Expressions after Myringotomy: An Animal Study.

OBJECTIVE The purpose of this study was to evaluate the effect of topical mitomycin C (MMC) on growth factor expression in tympanic membrane (TM) wound healing. MATERIALS AND METHODS Forty (20 male and 20 female) adult Wistar albino rats that varied from 250 to 300 g in weight were divided into five groups. In the first group, no intervention was performed, and the intact TMs were excised after the rats were sacrificed. In the other groups, both ears of rats underwent an electrocautery myringotomy procedure; MMC was applied to the right ears and saline to the left ones. In all groups, on the 3(rd), 7(th), 14(th), and 30(th) days, macroscopic examinations of TM patency and the expressions of transforming growth factor-β1 (TGF-β1), basic fibroblast growth factor (bFGF), and keratinocyte growth factor-1 (KGF-1) in TM epithelia, fibroblasts, and macrophages were performed by immunohistochemical staining and compared among the groups. RESULTS Complete healing was significantly less in the MMC group with respect to the saline group on the 7(th) and 14(th) days (p<0.05). On immunohistochemical study, no significant differences in the expressions of bFGF or KGF-1 were observed among the groups with one exception; on the 3rd day, the expression of TGF-β1 in macrophages was more elevated in the MMC group than in the saline group (p=0.001). CONCLUSION Application of MMC to acute perforations of the TM delays closure and has significant effects on some growth factors for certain durations.