Using the new official measures of concentration, this study finds a strong and highly significant correlation between concentration and industry profitability for South African manufacturing industries. This correlation is consistent with both the monopoly hypothesis of the traditional structure-conduct-performance paradigm and Demsetz's efficiency hypothesis that concentration of industry reflects the dominance of superior low-cost firms. Copyright 1997 Western Economic Association International.
e16306 Background: Duodenal adenocarcinoma (DA) is a rare malignancy with poor outcomes. Tumor markers are used to assess disease response and to monitor for recurrence. Specifically, CA-19-9 and CEA have been validated for use in pancreatic cancer and colorectal cancer, respectively. However, these tumor markers have never been validated in patients with DA. We aim to assess the association of these biomarkers with clinical outcomes in patients with DA. Methods: This is a retrospective cohort study. After obtaining IRB approval (IRB202102705), we accessed the University of Florida medical records of patient treated for DA from January 1, 2006, until December 31, 2021. CA 19-9 and CEA were collected as continuous variables and were analyzed as binary variables: normal vs. high, using the maximum normal value as a cut-off (normal CA 19-9 < = 35 U/ml; CEA < = 3 ng/ml). Analysis was conducted using Kaplan Meyer curves, log-rank test and Cox proportional hazards model. Results: A total of 68 patients were included in the final analysis. Median age was 67 years and median follow-up was 22.2 months. CA 19-9 and CEA were elevated in 36.8% and 48.5% of patients, respectively. Patients with an elevated CA 19-9 had a median overall survival (OS) of 8.5 months vs. 27.4 months in patients with normal levels (HR 1.67; 95%CI 0.94–2.99; p = 0.081). Patients with an elevated CEA had a median OS of 13.4 months vs. 16.8 months in patients with normal level normal levels (HR 1.43; 95%CI 0.81–2.52; p value = 0.221). In a sensitivity analysis, a concomitant elevation of both tumoral markers was significantly associated with worsened OS (HR 1.9; 95%CI 1.05–3.06; p = 0.035). Conclusions: In patients with duodenal adenocarcinoma, elevation of both CA 19-9 and CEA was associated with a statistically significant worse overall survival. CA 19-9 level had a higher prognostic impact on OS than CEA levels. To our knowledge, this is the first study to evaluate the role of CA 19-9 and CEA in patients with DA. Further research is required for validation.[Table: see text]
Pericardial effusion is defined as the accumulation of fluid between the visceral and parietal pericardium. The underlying etiology varies as any pathology that causes pericarditis or involves the pericardium can cause effusion. In practice, the majority of pericarditis cases are idiopathic, although these are assumed to be secondary to occult viral infection or inflammatory phenomena. Malignancy, particularly the metastatic spread of noncardiac primary tumors, has been implicated as a differential in the diagnosis of pericardial effusion. Though commonly seen in solid malignancies, effusion has been reported in hematologic malignancies such as myelodysplastic syndrome (MDS), acute leukemia, and lymphoma.Nonetheless, pericardial effusions associated with hematologic conditions are extremely rare with only one case report published describing pericardial effusion secondary to immune thrombocytopenia (ITP). We herein report the first documented case, to our knowledge, of pericardial effusion as an initial clinical manifestation of aplastic anemia in a middle-aged male presenting with pancytopenia.
Subclavian steal syndrome (SSS) refers to the phenomenon of retrograde flow in an ipsilateral branch of the subclavian artery due to hemodynamically significant stenosis or occlusion of the ipsilateral proximal subclavian artery. While SSS is usually asymptomatic, it can manifest as vertebrobasilar insufficiency (VBI), ischemia of the affected extremity, or cardiac angina when an internal mammary artery (IMA) is used as a bypass graft. The underlying etiology is most often atherosclerosis but can include Takayasu arteritis, thoracic outlet syndrome, cervical rib, and stenosis secondary to surgical repair of aortic coarctation or tetralogy of Fallot.There are several case reports describing unique presentations of SSS as well as limited reports of double SSS, where the brachiocephalic steno-occlusive disease causes flow reversal in both the ipsilateral vertebral and carotid arteries. We report herein the first documented case, to our knowledge, of a patient with SSS previously treated with left subclavian artery stenting and left common carotid-subclavian bypass who developed recurrent SSS in conjunction with orthostatic cerebral hypoperfusion syndrome (OCHOS) secondary to severe vasculopathy. She presented with recurrent, paroxysmal vertigo and nearsyncope associated with left upper extremity paresthesias that would only abate with sitting in the context of left subclavian artery stent restenosis and occlusion of her left common carotid-subclavian bypass graft. Interestingly, her initial presentation entailed retrograde flow from the left vertebral artery to the left subclavian artery, classic for SSS, but recurrence of her SSS involved retrograde flow from the left common carotid artery to the left subclavian artery, a phenomenon which has also not been described in the literature to our knowledge. As her symptoms of VBI appeared to be triggered by standing and not left arm movement, they were considered to be primarily secondary to OCHOS. Consequently, her primary treatment was to increase salt and fluid intake and thus increase intravascular volume for improved cerebral perfusion as she was not deemed to be a suitable candidate for regrafting of the left subclavian artery.
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