Magnesium yields opposite effects on the nuclear and cytosolic cascades of apoptosis in different rat brain regions.

OBJECTIVE: Magnesium is considered as potential neuroprotective and therapeutic agent, but certain studies have provided evidence of its apoptotic effectiveness in neurons. We aimed to evaluate the possible apoptotic effects of long-term magnesium use in healthy adult rat brains. MATERIALS AND METHODS: Magnesium citrate and magnesium glycinate compounds were administered orally to rats for 8 weeks (36 mg/kg). Expression levels of Bcl-2, Bax and Cyt-C genes were analyzed by real-time polymerase chain reactions (RT-PCR) in the prefrontal cortex, hippocampus and striatum regions. Bcl-2, Bax and CytC protein levels were measured using ELISA kits. Tissue sections were evaluated histopathologically with hematoxylin-eosin staining. RESULTS: Compared to the control group, the magnesium-administered groups indicated gene expression reductions in almost all brain regions; pro-apoptotic Bax, anti-apoptotic Bcl-2 and Cyt-C gene expression levels were reduced. With magnesium, the Bcl-2 and Bax protein levels were increased. Bax/Bcl-2 gene and protein ratio were also increased in the striatum and hippocampus, whereas Cyt-C protein levels were decreased or did not change in the magnesium treated groups. There was no pathological finding in histological evaluation. CONCLUSIONS: Long-term magnesium usage can promote apoptotic cascade in brain tissue by increasing Bax/Bcl-2 ratio. Cyt-C, a prominent factor processing caspase pathway, was decreased or unchanged. In addition, taking into account the histological evaluation, we supposed that the absence of Cyt-C in the cytosol can prevent the subsequent apoptotic pathway. Consequently, we obtained the findings of apoptotic initiation with magnesium in brain, but this cascade seems to be arrested at later stages.

The effect of Resveratrol and Octreotide on peritoneal adhesions in a rat model.

INTRODUCTION: The aim of this study was to investigate the efficacy of resveratrol and octreotide, agents that are used to prevent intra-abdominal adhesions in experimental models, in preventing intraperitoneal adhesions when used alone or in combination. MATERIALS AND METHODS: The study employed 28 young female Wistar albino rats weighing 250-300 grams. An experimental adhesion model was created in each rat using serosal abrasion and peritoneal excision. They were divided into four groups, each comprising seven rats: Group 1, adhesion induction only; Group 2, resveratrol administration only; Group 3, octreotide administration only; and Group 4, administration of resveratrol and octreotide combination. The rats were monitored under appropriate conditions for 14 days and then underwent laparotomy. Macroscopic intensity and extensiveness of adhesions and microscopic changes in the granulation tissue (cellular intensity, reticular and collagen fibers, capillaries, elastic and smooth muscle fibers, fibrosis) were evaluated and graded. Kruskal-Wallis and Mann-Whitney U-test were used in statistical analysis and the level of statistical significance was established as p <0.05. RESULTS: There was no significant difference between the groups in terms of the intensity and extensiveness of macroscopic adhesions (p=0.377 and p=0.319). There was a statistically significant difference between the microscopic scores of the groups according to Zühlke's classification (p=0.026). The Bonferroni correction used to test for the differences revealed that the rats in Group 1 achieved significantly higher scores than the rats in Group 3 (p=0.016). CONCLUSION: Octreotide showed higher efficiency compared to the control group in microscopic classification; however, the two agents were not superior to each other or their combination was not superior in preventing intra-abdominal adhesions.

Histochemical and immunohistochemical characteristics of elastofibromas.

Elastofibromas are slow-growing and rare soft-tissue tumors. The etiology and pathogenetic mechanisms are still controversial and there are only a few studies in the literature investigating the histochemical, immunohistochemical, and genetic features to determine the pathogenesis. We investigated the cellular composition of lesions with a diagnosis of elastofibroma in 17 patients by using histochemical and immunohistochemical methods. There were 17 cases with a mean age of 53.5 years. Mean lesion diameter was 6.6 cm. The immunohistochemical method showed vimentin and factor XIIIa positivity in all cases. Four cases had focal myoglobin positivity in the spindle-shaped cells between the collagen fibers. Spindle cells were positive for CD34 in 8 cases. Smooth muscle actin, desmin, type 4 collagen and laminin were negative in all cases. The elastic nature of the abnormal fibers was shown histoch with Verhoeff elastin staining and aldehyde fuchsin staining in all cases. Our results have shown that the concurrent positivity of factor XIIIa and CD34 in the cells forming the lesion might show that the lesionoriginates from primitive dermal mesenchymal cells. In addition, the myoglobin positivity found in some cases indicates the possibility of a myofibroblastic origin of elastofibromas.

The effect of radiocolloid preference on major parameters in sentinel lymph node biopsy practice in breast cancer.

INTRODUCTION: The possible effects of radiocolloid preference on sentinel lymph node biopsy (SLNB) were investigated. METHODS: A total of 200 patients with T1-2N0M0 breast cancer were evaluated. The first 100 patients underwent SLNB using (99m)Tc tin colloid (TC) and the next 100 using (99m)Tc nanocolloid (NC). Radiocolloid was injected intradermally at four quadrants of the periareolar region the day before surgery. All patients underwent lymphoscintigraphy 1 h after injection. All nodes having fourfold activity of the background were harvested using gamma probe. RESULTS: Sentinel lymph node (SLN) identification rate by gamma probe was 98% in each group. The number of SLNs identified by lymphoscintigraphy, gamma probe and pathological evaluation was 1.39 ± 0.7, 1.70 ± 1.0 and 2.23 ± 1.70 in the TC and 2.03 ± 0.94, 2.60 ± 1.36 and 3.05 ± 1.90 in the NC group, respectively (P<.05). Metastatic SLN was found in 24 (24.4%) of 98 patients in the TC group and 41 (41.8%) of 98 patients in the NC group (P=.04). None of the patients showed dispersion to internal mammarian lymph nodes. Lymphatic vessel visualization was observed in eight (8.1%) of 98 TC patients and in 47 (47.9%) of 98 NC patients (P=.000). SLNs were the only metastatic node(s) in 54.1% of TC and 73.1% of NC patients. CONCLUSION: The periareolar intradermal injection technique gives a high detection rate in the localization of SLNs independently from the choice of the tracer. Mean SLN numbers and lymphatic vessel visualization frequency were significantly higher using a smaller albumin Tc-99m nanocolloid as compared to a stannous fluoride Tc-99m tin colloid. The results of our study support the idea that the influence of increased number of SLNs on positive SLN frequency is critical.

Friedel oscillations are limiting the strength of superhard nanocomposites and heterostructures.

To obtain a deeper understanding of the mechanism of plastic deformation and failure in superhard nanocomposites and heterostructures we studied, by means of the ab initio density functional theory, the stress-strain response and the change of the electronic structure during tensile and shear deformation of a prototype interfacial systems consisting of 1 monolayer SiN sandwiched between a few nm thick TiN layers. This shows that peak Friedel oscillations of valence charge density weaken the Ti-N interplanar bonds next to that interface, where decohesion in tension and slip in shear occurs. These results provide ways to design new, stronger and harder materials.

Problematic aspects of sentinel lymph node biopsy and its relation to previous excisional biopsy in breast cancer.

PURPOSE: The aim of the study is to review problematic aspects of sentinel lymph node biopsy (SLNB) and to evaluate the influence of a previous excisional biopsy on these problems. MATERIALS AND METHODS: A total of 345 patients were evaluated retrospectively, 156 of them had a previous biopsy. Tc-99m tin colloid was injected the day before surgery at 4 quadrants around the areola intradermally. Problems complicating SLNB are reviewed in 3 topics: visualization or gamma probe detection problems, dilated lymphatic channels, and misleading activity accumulation. RESULTS: SLN detection rate and mean sentinel lymph node numbers were as follows in patients with and without biopsy, respectively: 95.5% versus 99.4% and 1.71 +/- 0.97 versus 1.70 +/- 0.92. Problems complicating the procedure occurred in 20 patients (5.8%). Among these 20 patients, 15 had a prior excisional biopsy, and incisions were located in the upper, outer and periareolar zones. Visualization or gamma probe detection problems occurred in 8 patients. Except for one with faint uptake in a sentinel node, all had a prior biopsy. Lymphatic channel dilatation complicated the procedure in 7 patients. Of these 7 patients, 4 had a previous biopsy. Misleading activity accumulations compromised SLNB in 5 patients, 4 of whom had a prior biopsy. CONCLUSION: Although SLNB is still applicable with a high success rate in cases with excisional biopsy, a review of problematic aspects of SLNB demonstrated a relation with the presence of a previous biopsy and its localization. The demonstration of nonvisualization preoperatively and the precise localization of atypically located activity accumulation may be helpful in the prevention of potential complications.

XELOX followed by XELIRI or the reverse sequence in advanced colorectal cancer.

BACKGROUND: Capecitabine has demonstrated high efficacy as first-line treatment for metastatic colorectal cancer (mCRC). In this non-randomized pilot study, we investigated the efficacy and safety of sequentially administered XELOX and XELIRI regimens or the reverse sequence in patients with advanced colorectal cancer. PATIENTS AND METHODS: Entry criteria were histologically confirmed mCRC, ECOG performance status (PS) < or =2 and adequate bone marrow, renal and hepatic function. All patients consecutively received XELOX followed by XELIRI at disease progression or vice versa. RESULTS: In multivariate analysis, independent prognostic factors with worse overall survival were: lower PS (p = 0.0001), multiple metastatic sites (p = 0.016) and high tumor grade. Higher serum levels of alkaline phosphatase and worse ECOG PS were associated with a shorter progression-free survival. Grade 3/4 mucositis, nausea/vomiting, grade 3/4 alopecia and grade 3 diarrhea were more frequent with XELIRI, whereas major toxicity events with XELOX were grade 3 neutropenia, thrombocytopenia and grade 2/3 neurotoxicity. CONCLUSION: Capecitabine appears to be an acceptable alternative to continuous-infusion fluorouracil (FU)/leucovorin (LV) in combination therapy and offers an effective, but more convenient alternative to continuous infusion FU/LV in the first-line treatment of patients with mCRC.

High-density liquidlike component facilitates plastic flow in a model amorphous silicon system.

Molecular dynamics simulations show that plastic deformation of amorphous Si modeled by the Stillinger-Weber potential is very sensitive to the density of the initial unstressed state. Low-density systems exhibit a pronounced yield phenomenon, strain softening, and a dramatic drop in pressure during deformation at a constant volume. This behavior is explained by the presence in every system of a certain concentration of solidlike and liquidlike components, the latter being denser and more amenable to plastic flow.

Nanocrystallization during nanoindentation of a bulk amorphous metal alloy at room temperature.

It is known that nanocrystallites can form in shear bands produced during severe bending or high-energy ball milling of thin ribbons of a metallic glass. We present direct experimental evidence that highly confined and controlled local contact at the ultrafine scale in the form of quasi-static nanoindentation of a bulk glassy metal alloy at room temperature can also cause nanocrystallization. Atomic force microscopy and transmission electron microscopy show that nanocrystallites nucleate in and around shear bands produced near indents and that they are the same as crystallites formed during annealing without deformation at 783 kelvin. Analogous to results from recent experiments with glassy polymers, our results are reasoned to be a consequence of flow dilatation inside the bands and of the attendant, radically enhanced, atomic diffusional mobility inside actively deforming shear bands.

An atypical presentation of metastatic gestational choriocarcinoma with maxillary sinus and subcutaneous involvement; report of a case with literature review.

Extragonadal germ cell tumors are rare neoplasms with histologic features comparable to those of gonadal origin. In this case report we present a 21-year-old female patient with an atypical localization of metastatic gestational choriocarcinoma. She was admitted to our hospital with recurrent epistaxis, abnormal vaginal bleeding, rectal bleeding, subcutaneous nodules on both thighs and forearms and left maxillary mass with intranasal cavity invasion. Laboratory analysis revealed significant elevation in serum beta-human chorionic gonodotropin (beta-HCG) level. Abdominal computerized tomography (CT) revealed left renal and retroperitoneal masses and thoracic CT displayed multiple bilateral lung metastases. Histopathological evaluation of the biopsy specimen obtained from the maxillary sinus showed choriocarcinoma. Based on WHO criteria she was classified as high-risk metastatic choriocarcinoma and treated with combination chemotherapy. We believe that in young women with recurrent epistaxis, gross abnormal vaginal and rectal bleeding and atypical maxillary sinus tumor with multiple lung metastases, choriocarcinoma should be included in the differential diagnosis and previous history of pregnancy or abortion should be obtained.