Pressure overload-induced transient oxidative stress mediates perivascular inflammation and cardiac fibrosis through angiotensin II.

Oxidative stress is implicated in the pathogenesis of various cardiovascular diseases. We have shown that in Wistar rats with a suprarenal aortic constriction (AC), pressure overload-induced transient perivascular inflammation (monocyte chemoattractant protein-1 [MCP-1] induction and macrophage accumulation) in the early phase is the determinant of reactive myocardial fibrosis and resultant diastolic dysfunction in the late phase. Thus, we investigated the role of reactive oxygen species production in cardiac remodeling in AC rats. Superoxide production and the footprint of lipid peroxidation were assessed using dihydroethidium staining and immunohistostaining against 4-hydroxy-2-nonenal (4-HNE), respectively. In sham rats, dihydroethidium and 4-HNE signals were scarcely found in the heart. At day 3, AC rats showed dihydroethidium signals mainly in the intramyocardial arterial wall, whereas modest 4-HNE staining was observed diffusely in the myocardium. These signals declined to lower levels by day 14 despite sustained hypertension. Chronic administration of a subdepressor dose of an angiotensin II type 1 receptor blocker candesartan reduced the pressure overload-induced dihydroethidium and 4-HNE signals at day 3. Moreover, candesartan decreased MCP-1 induction and macrophage infiltration at day 3 and prevented myocardial fibrosis at day 14, without affecting left ventricle and myocyte hypertrophy. In conclusion, acute pressure overload induced self-limited superoxide production mainly in the vascular wall. The reactive oxygen species production would contribute to the perivascular inflammation and subsequent myocardial fibrosis. Angiotensin II was suggested to have a pressure-independent effect on the reactive oxygen species production.     

Ectopic cervico-mediastinal thymoma confirmed by flow cytometric analysis of tumor-derived lymphocytes

Ectopic cervical or cervico-mediastinal thymomas are very rare and most of them are asymptomatic, except for the presence of a cervical mass. We present the case of a 71-year-old man with an ectopic cervico-mediastinal thymoma threatening superior vena cava syndrome. He had a slight headache and presented with venous dilatation on the chest wall. A computed tomographic scan and magnetic resonance, imaging of the chest demonstrated a mass extending from the right neck to the hilum, that indented the trachea and compressed and displaced the brachiocephalic veins anteriorly. Under a right hemicollar incision and median sternotomy, the mass was resected en bloc together with the thymus. The resected specimen was an encapsulated mass measuring 11×7×4 cm. The pathological diagnosis was type AB, non-invasive thymoma, confirmed by 3-color flow, cytometry of tumor-derived lymphocytes. Flow cytometry using biopsy material may contribute to the preoperative diagnosis of ectopic thymoma.     

HLA-restricted T lymphocyte-mediated cytotoxicity against herpes simplex virus-infected cells in humans.

Cytotoxic T lymphocytes (CTL) against herpes simplex virus (HSV) were induced in vitro from human peripheral blood lymphocytes by stimulation with HSV antigen. CTL generated by HSV type 1 (HSV-1) antigen stimulation killed not only HSV-1-infected target cells but also HSV type 2 (HSV-2)-infected target cells, though at a lower level. This evidence suggests that CTL against HSV recognize the HSV type-specific and type-common determinants on HSV-infected target cells. These CTL were generated from high responders against HSV-1 antigen as measured by antigen-specific T lymphocyte proliferation in vitro, but not to such an efficient degree from low responders. The cytotoxic activities of CTL against the allogeneic HSV-infected target cells were high when at least one of the HLA-A or -B antigens was shared. However, the HLA-A and -B nonidentical target cells were not killed effectively. The data presented here suggest the possibility of HLA restriction of HSV-specific CTL in humans.     

Increased and highly stable levels of functional soluble interleukin-6 receptor in sera of patients with monoclonal gammopathy

Soluble human interleukin-6 receptor (sIL-6R) was measured in the serum of 30 healthy individuals, 32 individuals with monoclonal gammopathy of undetermined significance (MGUS), 20 patients with early multiple myeloma (MM) and 54 patients with overt MM. The serum activity recognized by an immunoradiometric assay was determined to be sIL-6R, because of its binding capacity to IL-6 and its molecular mass of 55 kDa. All sera of healthy individuals contained sIL-6R (mean value: 89 ng/ml, range 17-300 ng/ml). Serum sIL-6R levels were increased by 51% in patients with MGUS (mean value: 135 ng/ml, p<0.005), by 44% in patients with early myeloma (mean value: 128 ng/ml, p<0.001) and by 116 % in patients with overt MM (mean value: 193 ng/ml, p<0.001). In patients with MM, a complete lack of correlation (p>0.7) was found between serum sIL-6R levels and other previously recognized prognostic factors in this disease, particularly serum IL-6 levels and those factors related to tumor cell mass. The independence of serum sIL-6R levels on tumor cell mass was directly demonstrated by studying four patients with MM treated with autologous bone marrow transplantation for periods of between 320 and 760 days. These levels were found to be remarkably stable and constant, independent of whether patients relapsed or achieved complete remission. Finally, physiological concentrations of sIL-6R were found to increase by tenfold the sensitivity of human myeloma cell lines to IL-6. These observations suggest a high control of the sIL-6R level in vivo, and, possibly, an important functional role of this circulating protein in patients with monoclonal gammopathies.     

Effect of focal X-ray irradiation on experimental choroidal neovascularization.

PURPOSE: Radiation therapy has been used to treat choroidal neovascularization (CNV) in patients with age-related macular degeneration. The in vivo effect of applying focal x-ray irradiation to the eye of rabbits with experimental CNV was investigated. METHODS: CNV was induced in the rabbit eyes by subretinal implantation of gelatin hydrogel microspheres impregnated with basic fibroblast growth factor. Three weeks after implantation, 17 of 34 eyes with CNV lesions accompanied by fluorescein leakage were irradiated with a single dose of 20 Gy; the other 17 eyes were not irradiated and served as the controls. The eyes were examined before irradiation and 1, 2, and 4 weeks after irradiation, by indirect ophthalmoscopy and fluorescein angiography. The degree of a decreasing amount of fluorescein leakage from the CNV lesions after irradiation was graded using a computerized image analysis system and was compared in the irradiated and nonirradiated eyes. These eyes were also examined histologically and immunohistochemically. RESULTS: Fluorescein leakage from the CNV lesions had significantly decreased in the eyes irradiated with 20 Gy compared with the control eyes, throughout the study period (P < 0.05). Histologic and immunohistochemical studies at 4 weeks after irradiation demonstrated that the degree of vascular formation and the number of vascular endothelial cells in the subretinal membrane of the irradiated eyes were less than those of the control eyes. CONCLUSIONS: Focal x-ray irradiation at the ocular region effectively reduced experimental CNV activity. These results support the possibility that radiation therapy may be beneficial in treating CNV.     

Targeted delivery of anti-angiogenic agent TNP-470 using water-soluble polymer in the treatment of choroidal neovascularization.

PURPOSE: The conjugation of drugs with water-soluble polymers such as poly(vinyl alcohol) (PVA) tends to prolong the half-life of drugs and facilitate the accumulation of drugs in tissues involving neovascularization. The purpose of this study was to evaluate the effect of TNP-470-PVA conjugate on the proliferation of endothelial cells in vitro and on experimental choroidal neovascularization (CNV) in vivo. METHODS: TNP-470 was conjugated in PVA by a dimethylaminopyridine-catalyzed reaction. The effects of TNP-470-PVA and free TNP-470 on the proliferation of human umbilical vein endothelial cells (HUVECs) and bovine retinal pigment epithelial cells (BRPECs) were evaluated by the tetrazolium-based colorimetric assay (XTT assay). Experimental CNV was induced by subretinal injection of gelatin microspheres containing basic fibroblast growth factor, into rabbits. Thirty rabbits were intravenously treated either with TNP-470-PVA (n = 8), free TNP470 (n = 5), free PVA (n = 5), or saline (n = 12) daily for 3 days, 2 weeks after implantation of gelatin microspheres. Fluorescein angiography was performed to detect the area with CNV, and the evaluation was made by computerized measurement of digital images. These eyes were also examined histologically. To observe the accumulation of conjugate, 3 rabbits with CNV received rhodamine B isothiocyanate-binding PVA (RITC-PVA), and the lesion was studied 24 hours later by fluorescein microscopy. RESULTS: The TNP-470-PVA inhibited the growth of HUVECs, similar to that of free TNP-470. The BRPECs were less sensitive to TNP-470-PVA than were the HUVECs. TNP-470-PVA significantly inhibited the progression of CNV in rabbits (P = 0.001). Histologic studies at 4 weeks after treatment demonstrated that the degree of vascular formation and the number of vascular endothelial cells in the subretinal membrane of the eyes treated with TNP-470-PVA were less than those of the control eyes. RITC-PVA remained in the area with CNV 24 hours after administration. CONCLUSIONS: These results suggest that TNP-470-PVA inhibited the proliferation of HUVECs more sensitively than that of BRPECs, and the targeted delivery of TNP-470-PVA may have potential as a treatment modality for CNV.     

Quantitative analysis of diabetic macular edema after scatter laser photocoagulation with the scanning retinal thickness analyzer

PURPOSE: To define the effect of scatter laser photocoagulation on foveal retinal thickness. METHODS: A commercial scanning retinal thickness analyzer was used to measure retinal thickness. The foveal retinal thickness was measured at the central area of the fundus (0.4 x 0.4 mm). The method was applied to 20 consecutive patients (mean age, 52.4 +/-16.9 years) with diabetic retinopathy. Measurements were performed before and 6 weeks after scatter photocoagulation. Patients were examined by fluorescein angiography and slit-lamp biomicroscopy to detect macular edema. RESULTS: Mean foveal thickness before scatter photocoagulation was 187+/-45 microm, increasing to 221+/-46 microm after the treatment (P = 0.0001). The foveal thickness increased in 12 eyes (60%). Laser treatment increased macular permeability in two eyes (10%). Biomicroscopic examination revealed central macular thickening in one eye (5%). Visual acuity was reduced in four eyes (20%). CONCLUSIONS: Our results suggest that subclinical macular edema occurs after scatter laser photocoagulation. The retinal thickness analyzer is a sensitive tool for early detection of macular edema after laser treatment, because increases in retinal thickness as small as 34 microm cannot be assessed by slit-lamp biomicroscopy.     

Neural cell adhesion molecule expression in thyroid cancer

Neural cell adhesion molecule (NCAM) is an integral membrane glycoprotein that participates in cell-cell interactions. We examined the expression of neural cell adhesion molecule (NCAM) by immunohistochemistry in 65 cases of thyroid disease. In the majority of thyroid tumors, NCAM expression was detected in tumor cells. In chronic thyroiditis, Hurthle cells demonstrated expression of NCAM. In normal thyroid gland, neither follicular nor parafollicular cells expressed NCAM at detectable levels. All papillary carcinomas and most poorly differentiated follicular carcinomas and some follicular adenomas demonstrated NCAM expression. In thyroid carcinoma, clinical stage and recurrent laryngeal nerve paralysis did not correlate significantly with expression of NCAM. Papillary carcinomas with strong expression of NCAM were more likely to have extra capsular invasion. It is supposed that immunohistochemical detection of NCAM expression supports histologic diagnosis and offers prognostic information.