115 research outputs found

    Petrology, Mineral and Isotope Geochemistry of the External Liguride Peridotites (Northern Apennines, Italy)

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    Mantle peridotites of the External Liguride (EL) units (Northern Apennines) represent slices of subcontinental lithospheric mantle emplaced at the surface during early stages of rifting of the Jurassic Ligurian Piemontese basin. Petrological, ion probe and isotopic investigations have been used to unravel the nature of their mantle protolith and to constrain the timing and mechanisms of their evolution. EL peridotites are dominantly fertile spinel Iherzolites partly recrystallizfd in the plagiodase Iherzplite stability field Clinopyroxenes stable in the spinel-facies assemblage have nearly fiat REE patterns (CeN/SmN=0·6-0·8) at (10-16)×C1 and high Na, Sr, Ti and Zr contents. Kaersutitic-Ti-pargasitic amphiboles also occur in the spinel-facies assemblage. Their LREE-depleted REE spectra and very low Sr, Zr and Ba contents indicate that they crystallized from hydrous fluids with low concentrations of incompatible elements. Thermometric estimates on the spinelfacies parageneses yield lithospheric equilibrium temperatures in the range 1000-1100°C, in agreement with the stability of amphibole, which implies T<1100°C. Sr and Nd isotopic compositions, determined on carefully handpicked clinopyroxene separates, plot within the depleted end of the MORB field (87Sr/86Sr=0·70222-0·70263; 143Nd/144Nd=0·513047-0·513205) similar to many subcontinental orogenic spinel Iherzolites from the western Mediterranean area (e.g. Ivrea Zpne and Lanzfl N). The interpretation of the EL Iherzolites as subcontinental lithospheric mantle is reinforced by the occurrence of one extremely depleted isotopic composition (87Sr/86Sr=0·701736; 143Nd/144Nd=0·513543). Sr and Nd model ages, calculated assuming both CHUR and DM mantle sources, range between 2·4 Ga and 780 Ma. In particular, the 1·2-Ga Sr age and the 780-Ma Nd age can be regarded as minimum ages of differentiation. The transition from spinel-to plagioclase-facies assemblage, accompanied by progressive deformation (from granular to tectonite-mylonite textures), indicate that the EL Iherzolites experienced a later, subsolidus decompressional evolution, starting from subcontinental lithospheric levels. Sm/Nd isochrons on plagioclase-clinopyroxene pairs furnish ages of ∽165 Ma. This early Jurassic subsolidus decompressional history is consistent with uplift by means of denudation in response to passive and asymmetric lithospheric extension. This is considered to be the most suitable geodynamic mechanism to account for the exposure of huge bodies of subcontinental lithospheric mantle during early stages of opening of an oceanic basi

    Working Memory in Collegiate Athletes and Non-Athletes: A Comparison of Team-Sports Athletes, Solo-Sports Athletes, Frequent Exercisers and Infrequent Exercisers

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    Past research suggests that exercise is associated with improved working memory (WM) abilities, and that athletes have better executive functioning and WM skills than non-athletes. However, no studies to date have separated the effects of exercise from the effects of athletic participation when examining WM. This study had three primary goals: (1) to determine whether amateur college athletes have better auditory and visual WM than their non-athlete peers who exercise frequently and whether non-athlete frequent exercisers have better WM than non-athlete infrequent exercisers (2) to determine whether amateur participation in particular types of sports (team-based versus solo sports) corresponds to differences in auditory or visual WM, and (3) to examine whether gender plays a role in the relationships between exercise, athletic participation and WM. This study was a cross-sectional, correlational design that examined WM in men versus women college students divided into four groups (team-sports athletes, solo-sports athletes, frequent exercisers, and infrequent exercisers). 153 college students completed five tests of auditory (Digit Span subtest, PASAT) and visual (Spatial Span subtest, N-Back, WCST) WM. Collegiate men who participated in team-based sports outperformed collegiate men who participated in solo-sports in auditory WM. The two non-athlete groups (frequent and infrequent exercisers) earned scores between those of the two athlete groups. Male infrequent exercisers demonstrated better visual WM than the other three male athlete/exerciser groups. In contrast, neither athletic participation nor exercise affected collegiate women’s WM abilities. Our results did not support our hypothesis that all types of student athletes would exhibit better WM than students who exercise regularly but do not engage in competitive sports. Additionally, our data did not indicate that frequent exercise is associated with stronger WM skills than infrequent exercise in non-athlete college students. Participation in team-based sports was associated with better auditory WM skills than participation in solo sports, but this was only true for male, not female, athletes. Thus, gender was an important factor in delineating the relationships between exercise, athletic participation and WM

    Appendiceal Mucocele in an Elderly Patient: How Much Surgery?

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    Appendiceal mucoceles are rare cystic lesions with an incidence of 0.3–0.7% of all appendectomies. They are divided into four subgroups according to their histology. Even though the symptoms may vary – depending on the level of complication – from right lower quadrant pain, signs of intussusception, gastrointestinal bleeding to an acute abdomen with sepsis, most mucoceles are asymptomatic and found incidentally. We present the case of a 70-year-old patient with an incidentally found appendiceal mucocele. He was seen at the hospital for backache. The CT scan showed a vertebral fracture and a 7-cm appendiceal mass. A preoperative colonoscopy displayed several synchronous adenomas in the transverse and left colon with high-grade dysplasia. In order to lower the cancer risk of this patient, we performed a subtotal colectomy. The appendiceal mass showed no histopathological evidence of malignancy and no sign of perforation. The follow-up was therefore limited to 2 months. In this case, appendectomy would have been sufficient to treat the mucocele alone. The synchronous high-grade dysplastic adenomas were detected in the preoperative colonoscopy and determined the therapeutic approach. Generally, in the presence of positive lymph nodes, a right colectomy is the treatment of choice. In the histological presence of mucinous peritoneal carcinomatosis, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy is indicated. In conclusion, mucoceles of the appendix are detected with high sensitivity by CT scan. If there is no evidence of synchronous tumor preoperatively and no peritoneal spillage, invasion or positive sentinel lymph nodes during surgery, a mucocele is adequately treated by appendectomy

    Bladder metastases of appendiceal mucinous adenocarcinoma: a case presentation

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    <p>Abstract</p> <p>Background</p> <p>Appendiceal adenocarcinoma is rare with a frequency of 0.08% of all surgically removed appendices. Few cases of appendiceal carcinoma infiltrating the bladder wall for spatial contiguity have been documented.</p> <p>Case Presentation</p> <p>A case is reported of a 45-years old woman with mucinous cystadenocarcinoma of the appendix with bladder metastasis. Although ultrasonography and voided urinary cytology were negative, abdomen computed tomography (CT) scan and cystoscopy and subsequent pathological examination revealed a mass exclusively located in the anterior wall of the bladder. Histopathology of the transurethral bladder resection revealed a bladder adenocarcinoma [6 cm (at the maximum diameter) × 2,5 cm; approximate weight: 10 gr] with focal mucinous aspects penetrating the muscle and perivisceral fat. Laparotomy evidenced the presence of a solid mass of the appendix (2,5 cm × 3 cm × 2 cm) extending to the loco-regional lymph nodes. Appendectomy and right hemicolectomy, linfoadenectomy and partial cystectomy were performed. The subsequent pathological examination revealed a mucinous cystadenocarcinoma of the appendix with metastatic cells colonising the anterior bladder wall and several colic lymph nodes.</p> <p>Conclusions</p> <p>The rarity of the appendiceal carcinoma invading the urinary bladder and its usual involvement of nearest organs and the posterior bladder wall, led us to describe this case which demonstrates the ability of the appendiceal cancer to metastasize different regions of urinary bladder.</p

    Intricacies in the surgical management of appendiceal mucinous cystadenoma: a case report and review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>Mucinous cystadenoma is a type of mucocele of the appendix that is rarely encountered in clinical practice. Dogmatic consensus on the optimal surgical modus operandi of appendicular mucocele is lacking in the literature and this remains a subject of controversy. There is little agreement with regard to the best procedure (right hemicolectomy versus appendectomy) or the best surgical approach (laparoscopic versus laparotomy).</p> <p>Case presentation</p> <p>We report the case of a 70-year-old Asian woman from Karachi who presented with pain in the right iliac fossa for 15 days. On physical examination, a mobile and firm mass was palpable in the right iliac fossa. A colonoscopy was performed which showed external compression of the cecum. A biopsy of the mucosa was normal. Computed tomography scan showed a mucocele of the appendix with minimal periappendiceal fat stranding. She underwent an initial diagnostic laparoscopy to evaluate any mucin spillage in the peritoneal cavity. Once no spillage was identified, an open appendectomy was then performed. Intra-operatively, a frozen section of the appendiceal sample was sent to ascertain the need for an extension of surgery to a right hemicolectomy. Absence of any malignancy on the frozen section obviated the need for a surgical extension. The final histopathological examination showed a mucinous cystadenoma of the appendix. The patient was symptom-free at one year after surgery.</p> <p>Conclusion</p> <p>It is important to distinguish between mucinous cystadenomas and mucinous cystadenocarcinomas. However, this distinction remains elusive in the pre-operative setting. A simple appendectomy using an intra-operative frozen section appears to be a reasonable surgical approach for selected cases with an intact mucocele of the appendix. However, long-term follow-up is warranted in such patients to evaluate the risks of using this approach.</p

    Surgical treatment of giant mesenteric fibromatosis presenting as a gastrointestinal stromal tumor: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Intra-abdominal fibromatosis, usually located at the mesenteric level, is a locally invasive tumor of fibrous origin, with no ability to metastasize, but a tendency to recur. Certain non-typical cases of intra-abdominal fibromatosis with involvement of the bowel wall can be misdiagnosed because of their different biological behavior.</p> <p>Case presentation</p> <p>We describe the case of a 64-year-old Caucasian man presenting with mesenteric fibromatosis and involvement of the bowel wall, who was treated surgically. The macroscopic and microscopic appearance of the lesion mimicked a gastrointestinal stromal tumor, a tumor with potential malignant behavior.</p> <p>Conclusion</p> <p>It is essential to make an early and correct diagnosis in such equivocal cases, so that the appropriate treatment can be chosen and suitable patients admitted to clinical trials if appropriate. New and reliable criteria for discriminating between intra-abdominal fibromatosis and gastrointestinal stromal tumor should be proposed and established because novel sophisticated therapeutic strategies have been introduced in the international literature.</p

    Metabolic Effects of n-3 PUFA as Phospholipids Are Superior to Triglycerides in Mice Fed a High-Fat Diet: Possible Role of Endocannabinoids

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    Background n-3 polyunsaturated fatty acids, namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), reduce the risk of cardiovascular disease and can ameliorate many of obesity-associated disorders. We hypothesised that the latter effect will be more pronounced when DHA/EPA is supplemented as phospholipids rather than as triglycerides. Methodology/Principal Findings In a ‘prevention study’, C57BL/6J mice were fed for 9 weeks on either a corn oil-based high-fat obesogenic diet (cHF; lipids ~35% wt/wt), or cHF-based diets in which corn oil was partially replaced by DHA/EPA, admixed either as phospholipids or triglycerides from marine fish. The reversal of obesity was studied in mice subjected to the preceding cHF-feeding for 4 months. DHA/EPA administered as phospholipids prevented glucose intolerance and tended to reduce obesity better than triglycerides. Lipemia and hepatosteatosis were suppressed more in response to dietary phospholipids, in correlation with better bioavailability of DHA and EPA, and a higher DHA accumulation in the liver, white adipose tissue (WAT), and muscle phospholipids. In dietary obese mice, both DHA/EPA concentrates prevented a further weight gain, reduced plasma lipid levels to a similar extent, and tended to improve glucose tolerance. Importantly, only the phospholipid form reduced plasma insulin and adipocyte hypertrophy, while being more effective in reducing hepatic steatosis and low-grade inflammation of WAT. These beneficial effects were correlated with changes of endocannabinoid metabolome in WAT, where phospholipids reduced 2-arachidonoylglycerol, and were more effective in increasing anti-inflammatory lipids such as N-docosahexaenoylethanolamine. Conclusions/Significance Compared with triglycerides, dietary DHA/EPA administered as phospholipids are superior in preserving a healthy metabolic profile under obesogenic conditions, possibly reflecting better bioavalability and improved modulation of the endocannabinoid system activity in WA

    Growth Inhibition and Apoptosis Induced by Osthole, A Natural Coumarin, in Hepatocellular Carcinoma

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    BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed tumors worldwide and is known to be resistant to conventional chemotherapy. New therapeutic strategies are urgently needed for treating HCC. Osthole, a natural coumarin derivative, has been shown to have anti-tumor activity. However, the effects of osthole on HCC have not yet been reported. METHODS AND FINDINGS: HCC cell lines were treated with osthole at various concentrations for 24, 48 and 72 hours. The proliferations of the HCC cells were measured by MTT assays. Cell cycle distribution and apoptosis were determined by flow cytometry. HCC tumor models were established in mice by subcutaneously injection of SMMC-7721 or Hepa1-6 cells and the effect of osthole on tumor growths in vivo and the drug toxicity were studied. NF-κB activity after osthole treatment was determined by electrophoretic mobility shift assays and the expression of caspase-3 was measured by western blotting. The expression levels of other apoptosis-related genes were also determined by real-time PCR (PCR array) assays. Osthole displayed a dose- and time-dependent inhibition of the HCC cell proliferations in vitro. It also induced apoptosis and caused cell accumulation in G2 phase. Osthole could significantly suppress HCC tumor growth in vivo with no toxicity at the dose we used. NF-κB activity was significantly suppressed by osthole at the dose- and time-dependent manner. The cleaved caspase-3 was also increased by osthole treatment. The expression levels of some apoptosis-related genes that belong to TNF ligand family, TNF receptor family, Bcl-2 family, caspase family, TRAF family, death domain family, CIDE domain and death effector domain family and CARD family were all increased with osthole treatment. CONCLUSION: Osthole could significantly inhibit HCC growth in vitro and in vivo through cell cycle arrest and inducing apoptosis by suppressing NF-κB activity and promoting the expressions of apoptosis-related genes

    Paradoxical co-existing base metal sulphides in the mantle: The multi-event record preserved in Loch Roag peridotite xenoliths, North Atlantic Craton

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    The role of the subcontinental lithospheric mantle as a source of precious metals for mafic magmas is contentious and, given the chalcophile (and siderophile) character of metals such as the platinum-group elements (PGE), Se, Te, Re, Cu and Au, the mobility of these metals is intimately linked with that of sulphur. Hence the nature of the host phase(s), and their age and stability in the subcontinental lithospheric mantle may be of critical importance. We investigate the sulphide mineralogy and sulphide in situ trace element compositions in base metal sulphides (BMS) in a suite of spinel lherzolite mantle xenoliths from northwest Scotland (Loch Roag, Isle of Lewis). This area is situated on the margin of the North Atlantic Craton which has been overprinted by a Palaeoproterozoic orogenic belt, and occurs in a region which has undergone magmatic events from the Palaeoproterozoic to the Eocene. We identify two populations of co-existing BMS within a single spinel lherzolite xenolith (LR80) and which can also be recognised in the peridotite xenolith suite as a whole. Both populations consist of a mixture of Fe-Ni-Cu sulphide minerals, and we distinguished between these according to BMS texture, petrographic setting (i.e., location within the xenolith in terms of ‘interstitial’ or within feldspar-spinel symplectites, as demonstrated by X-ray Computed Microtomography) and in situ trace element composition. Group A BMS are coarse, metasomatic, have low concentrations of total PGE (&lt; 40 ppm) and high (Re/Os)N (ranging 1 to 400). Group B BMS strictly occur within symplectites of spinel and feldspar, are finer-grained rounded droplets, with micron-scale PtS (cooperite), high overall total PGE concentrations (15–800 ppm) and low (Re/Os)N ranging 0.04 to 2. Group B BMS sometimes coexist with apatite, and both the Group B BMS and apatite can preserve rounded micron-scale Ca-carbonate inclusions indicative of sulphide-carbonate-phosphate immiscibility. This carbonate-phosphate metasomatic association appears to be important in forming PGE-rich sulphide liquids, although the precise mechanism for this remains obscure. As a consequence of their position within the symplectites, Group B BMS are particularly vulnerable to being incorporated in ascending mantle-derived magmas (either by melting or physical entrainment). Based on the cross-cutting relationships of the symplectites, it is possible to infer the relative ages of each metasomatic BMS population. We tally these with major tectono-magmatic events for the North Atlantic region by making comparisons to carbonatite events recorded in crustal and mantle rocks, and we suggest that the Pt-enrichment was associated with a pre-Carboniferous carbonatite episode. This method of mantle xenolith base metal sulphide documentation may ultimately permit the temporal and spatial mapping of the chalcophile metallogenic budget of the lithospheric mantle, providing a blueprint for assessing regional metallogenic potential. Abbreviations: NAC, North Atlantic Craton; GGF, Great Glen Fault; NAIP, North Atlantic Igneous Province; BPIP, British Palaeogene Igneous Province; SCLM, subcontinental lithospheric mantle; PGE, platinum-group elements; HSE, highly siderophile elements; BMS, base metal sulphid
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