Differentiation of viable and nonviable myocardium by the use of three-dimensional tagged MRI in 2-day-old reperfused canine infarcts

BACKGROUND: To limit ischemic myocardial injury, it is important to differentiate viable from infarcted myocardium. Three dimensional (3D) tagged MRI has the ability to quantify myocardial 3D deformation and strain (noninvasively and precisely), and can achieve a true comparison of contraction not only from region to region, but also at different levels of function. In this study, we investigated whether regional strain mapping obtained by 3D-tagged MRI can differentiate between viable but stunned myocardium and nonviable myocardium. METHODS AND RESULTS: We examined 7 dogs 2 days after a 90-minute closed-chest left anterior descending coronary artery occlusion followed by 48 hours of reperfusion. 3D-tagged MR images spanning the entire left ventricle were acquired both at rest and during dobutamine infusion (5 microg. kg-1. min-1 IV). Regional blood flow was measured with radioactive microspheres and used to define risk regions. Infarcted regions were defined as 2,3,5 triphenyltetrazolium chloride negative regions. Strains in infarcted regions were greatly impaired compared with remote regions (P<0.001) and remained unchanged during dobutamine stress. Risk regions showed a dysfunction at rest, with improved function during dobutamine infusion. Receiver operating characteristics analysis showed that radial strain was more accurate for identifying viable regions. CONCLUSIONS: When coupled with a stress test, 3D strain mapping by the use of tagged MRI is a sensitive and noninvasive method for characterizing ischemic injury. Regional strain can be used to differentiate between viable but stunned and nonviable myocardium within the postischemic injured myocardium.     

原发性小肠肿瘤64例临床分析

原发性小肠肿瘤缺乏特征性症状,早期诊断比较困难,误诊率高。现对我院１９９０～１９９７年收治经手术和病理证实的６４例小肠原发性肿瘤进行分析,以提高对此病的认识及诊断水平。临床资料一、性别与年龄６４例中,男４１例,女２３例。年龄为２．５～７９岁,平均５１岁,６２．５％属５０岁以上。二、临床表现不等程度的腹痛４３例（６７．２％）,由２日至３年,腹部肿块２０例（３１．３％）;梗阻性黄疸１９例（２９．９％）,主要见于十二指肠乳头部癌;出血：反复黑便或柏油样便１８例（２８．１％）,少数为血便;肠梗阻９例（１…     

Overexpression of cyclin D1 in the Dami megakaryocytic cell line causes growth arrest

The maturation of megakaryocytes in vivo requires polyploidization or repeated duplication of DNA without cytokinesis. As DNA replication and cytokinesis are tightly regulated in somatic cells by cyclins and cyclin-dependent kinases, we sought to determine the pattern of cyclin gene expression in cells that undergo megakaryocytic differentiation and polyploidization. The Dami megakaryocytic cell line differentiates and increases ploidy in response to phorbol 12-myristate 13-acetate (PMA) stimulation in vitro. We used Northern blotting to analyze mRNA levels of cyclins A, B, C, D1, and E in PMA-induced Dami cells and found that cyclin D1 mRNA levels increased dramatically (18-fold). Similar increases in cyclin D1 mRNA were obtained for other cell lines (HEL and K562) with megakaryocytic properties, but not in HeLa cells. The increase in cyclin D1 was confirmed by Western immunoblotting of PMA-treated Dami cells. This finding suggested that cyclin D1 might participate in megakaryocyte differentiation by promoting endomitosis and/or inhibiting cell division. To address these possibilities, we constructed two stable Zn+2-inducible, cyclin D1-overexpressing Dami cell lines. Cyclin D1 expression alone was not sufficient to induce polyploidy, but in conjunction with PMA-induced differentiation, polyploidization was slightly enhanced. However, unlike other cell systems, cyclin D1 overexpression caused cessation of cell growth. Although the mechanism by which cyclin D1 may affect megakaryocyte differentiation is not clear, these data demonstrate that cyclin D1 is upregulated in differentiating megakaryocytic cells and may contribute to differentiation by arresting cell proliferation.     

The insulin receptor substrate-1-related 4PS substrate but not the interleukin-2R gamma chain is involved in interleukin-13-mediated signal transduction

Interleukin-13 (IL-13) induced a potent mitogenic response in IL-3- dependent TF-1 cells and DNA synthesis to a lesser extent in MO7E and FDC-P1 cells. IL-13 stimulation of these lines, like IL-4 and insulin- like growth factor-1 (IGF-1), resulted in tyrosine phosphorylation of a 170-kD substrate. The tyrosine-phosphorylated 170-kD substrate strongly associated with the 85-kD subunit of phosphoinositol-3 (PI-3) kinase and with Grb-2. Anti-4PS serum readily detected the 170-kD substrate in lysates from both TF-1 and FDC-P1 cells stimulated with IL-13 or IL-4. These data provide evidence that IL-13 induces tyrosine phosphorylation of the 4PS substrate, providing an essential interface between the IL- 13 receptor and signaling molecules containing SH2 domains. IL-13 and IL-4 stimulation of murine L cell fibroblasts, which endogenously express the IL-4 receptor (IL-4R alpha) and lack expression of the IL-2 receptor gamma subunit (IL-2R gamma), resulted in tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1)/4PS. Enhanced tyrosine phosphorylation of IRS-1/4PS was observed in response to IL-4, but not IL-13 treatment of L cells transfected with the IL-2R gamma chain. These results indicate that IL-13 does not use the IL-2R gamma subunit in its receptor complex and that expression of IL-2R gamma enhances, but is not absolutely required for mediating IL-4-induced tyrosine phosphorylation of IRS-1/4PS.     

Interferon-alpha alters spectrin organization in normal and leukemic human B lymphocytes

Interferon-alpha (IFN-alpha) regulates the growth, differentiation, and recirculation of normal and malignant B lymphocytes. In this report we examine the effects of IFN-alpha on the distribution of the cytoskeletal protein spectrin in peripheral blood B lymphocytes from normal donors and patients diagnosed with chronic lymphocytic leukemia (CLL) and hairy cell leukemia (HCL). Exposure of normal and leukemic B cells to IFN-alpha in vitro was shown by immunofluorescence microscopy to cause a dose-dependent increase in the percentage of cells containing discrete focal accumulations of spectrin, ie, a single large aggregate or cap-like structure near the plasma membrane. Although the magnitude of this effect was variable among individual patient samples, in some experiments IFN-alpha induced a fourfold increase in the percentage of leukemic B cells exhibiting focal accumulations of spectrin. Spectrin reorganization induced by IFN-alpha was abrogated by the protein synthesis inhibitor cycloheximide. In addition, IFN-alpha increased the total cellular content of spectrin in B-CLL cells by approximately twofold to fourfold. Finally, a role for protein kinase C in mediating the effects of IFN-alpha on spectrin's organization is implicated by studies in which calphostin C inhibited the IFN-induced focal accumulation of spectrin. Taken together, these studies suggest that the immunomodulatory activities of IFN-alpha in normal and malignant B cells involve a change in the organization of the spectrin- based cytoskeleton.     

Risk factors of recurrent choledocholithiasis following therapeutic endoscopic retrograde cholangiopancreatography

Background: The risk factors for the recurrent choledocholithiasis after endoscopic retrograde cholangiopancreatography(ERCP) have not been well studied. The aim of this study was to explore the risk factors of recurrent choledocholithiasis. Methods: We carried out a retrospective analysis of data collected between January 1, 2010 and January 1, 2020. Univariate analysis and multivariate analysis were used to explore the independent risk factors of recurrent choledocholithiasis following therape...     

Paraaortic lymph node irradiation in cervical carcinoma without prior lymphadenectomy

A study of complications associated with paraaortic irradiation was undertaken in patients with uterine cervical cancer who had not undergone prior lymphadenectomy. Between 1975 and 1984, 29 highly selected patients received paraaortic irradiation as part of their definitive treatment for cervical carcinoma. Paraaortic fields were irradiated to a total dose of 4,200-5,000 rad (42-50 Gy), in fractions of 150-180 rad (1.5-1.8 Gy). An anteroposterior-posteroanterior technique was generally used. All fields were treated every day. There were no instances of small-bowel obstruction or other major complications, surgical procedures, or deaths caused by paraaortic irradiation. Eleven patients (38%) have no evidence of recurrent disease 23-120 months after completion of therapy. Paraaortic irradiation was well tolerated in this patient group without prior staging lymphadenectomy. Thus, in selected patients and with appropriate techniques, paraaortic irradiation for cervical carcinoma may be used with relative safety.     

Brainstem glioma progression in juvenile and adult rats

OBJECT： Brainstem gliomas are common in children and have the worst prognosis of any brain tumor in this age group. On the other hand, brainstem gliomas are rare in adults, and the authors of some clinical studies have suggested that this lesion behaves dif ferently in adults than in children. In the present study, the authors test an orthotopic C6 brainstem glioma model in juvenile and adult rats, and investigate the biological behavior of this lesion in the 2 age groups. METHODS： The C6 glioma cells were stereotacti eally implanted into the pons of juvenile or adult male rats. Neurological presentation and survival time were recorded.