[Risk Factors for Early Progression of Carotid Stenosis after Cervical Radiation Therapy].

OBJECTIVE: Carotid stenosis may occur as a late complication following cervical radiation therapy(RT);however, it may also progress in the early post-RT period. This study aimed to characterize the clinical features associated with the early progression of post-RT carotid stenosis. METHODS: We retrospectively reviewed clinical records of 30 patients who had undergone unilateral or bilateral cervical RT between January 2010 and November 2014. We analyzed the pre- and post-RT stenosis of their carotid arteries using contrast-enhanced computed tomography images. The arteries were classified as progressive or non-progressive according to the presence or absence of stenosis progression within five years after RT. Using univariate and multivariate analyses, we evaluated the following potential clinical risk factors:age;gender;history of hypertension, hyperlipidemia, diabetes mellitus, coronary artery disease, or smoking habit;antiplatelet or statin use;radiation dose;and prior presence of carotid stenosis before RT. RESULTS: In total, we reviewed 57 irradiated carotid arteries and identified 9 with early post-RT progression. Carotid stenosis before RT was observed in 88.9% of arteries in the progressive group but only 2% of arteries in the non-progressive group and it predicted progression(univariate and multiple logistic regression analyses, p<0.0001). No other clinical characteristics had a significant association with the progression of carotid stenosis. CONCLUSION: Prior presence of carotid stenosis may be a risk factor for its early progression after RT. Pre-RT screening of cervical arteries may be useful, and strict management of carotid stenosis is critical in patients with cervical radiation therapy.

HBME-1 and CD15 immunocytochemistry in the follicular variant of thyroid papillary carcinoma.

Papillary carcinoma is the most common thyroid malignancy. As the cytological diagnosis of papillary carcinoma is not difficult in patients with the usual type of lesion, fine-needle aspiration (FNA) cytology is an effective method for preoperative evaluation. However, this modality is often ineffective in identifying the follicular variant of papillary thyroid carcinoma (FVPTC) due to its similarity to other follicular lesions and the incompleteness of typical nuclear features. Therefore, we investigated the expression of immunocytochemical markers of papillary carcinoma in cytological specimens of FVPTC and evaluated their utilities. The immunoreactivity of HBME-1 and CD15 was investigated using 50 imprint smear cytological specimens obtained from thyroid lesions, including 13 FVPTC. The sensitivity and specificity of HBME-1 for FVPTC were 92% and 89%, respectively, while those of CD15 were 23% and 100%, respectively. In conclusion, HBME-1 is a sensitive marker of papillary carcinoma, including both usual type and FVPTC, in cytological specimens. Therefore, using HBME-1 immunocytochemistry in FNA cytology will lead to reduction of the incidence of false-negative diagnoses of FVPTC. Although CD15 is apparently inferior in terms of sensitivity for FVPTC, its excellent specificity will support the definitive diagnosis of thyroid malignancies, including FVPTC, after screening with HBME-1.

Surface-bound basement membrane components accelerate amyloid-ß peptide nucleation in air-free wells: an in vitro model of cerebral amyloid angiopathy.

Cerebral amyloid angiopathy is caused by deposition of the amyloid ß-peptide which consists of mainly 39-40 residues to the cortical and leptomeningeal vessel walls. There are no definite in vitro systems to support the hypothesis that the vascular basement membrane may act as a scaffold of amyloid ß-peptide carried by perivascular drainage flow and accelerate its amyloid fibril formation in vivo. We previously reported the critical roles of interfaces and agitation on the nucleation of amyloid fibrils at low concentrations of amyloid ß-peptide monomers. Here, we reproduced the perivascular drainage flow in vitro by using N-hydroxysuccinimide-Sepharose 4 Fast flow beads as an inert stirrer in air-free wells rotated at 1rpm. We then reproduced the basement membranes in the media of cerebral arteries in vitro by conjugating Matrigel and other proteins on the surface of Sepharose beads. These beads were incubated with 5µM amyloid ß(1-40) at 37°C without air, where amyloid ß(1-40) alone does not form amyloid fibrils. Using the initiation time of fibril growth kinetics (i.e., the lag time of fibril growth during which nuclei, on-pathway oligomers and protofibrils are successively formed) as a parameter of the efficiency of biological molecules to induce amyloid fibril formation, we found that basement membrane components including Matrigel, laminin, fibronectin, collagen type IV and fibrinogen accelerate the initiation of amyloid ß-peptide fibril growth in vitro. These data support the essential role of vascular basement membranes in the development of cerebral amyloid angiopathy.

[An autopsied case of zygomycosis invasing in the central nervous system and vessels, which is difficult in the differential diagnosis from aspergillosis].

A 59-year-old man with a long history of under-treated diabetes mellitus presented with severe inflammation that had spread from the sinus to the left orbital cavity. The bilateral internal carotid arteries were severely stenotic, causing multiple infarctions in the brain parenchyma. There was no ß-D-glucan detected in the cerebrospinal fluid. Based on the presence of central nervous system (CNS) inflammation and vascular involvements that spread from the sinusitis, we tentatively diagnosed this patient as having invasive fungal CNS infection, i.e. zygomycosis or aspergillosis. Although the patient was treated with anti-fungal drugs such as liposomal amphotericin B and voriconazole, he died of respiratory failure. Pathological examination of the autopsied tissues demonstrated zygomycosis in the brain and heart. The prevalence of zygomycosis is generally very low (-5% of CNS infections) compared with that of other fungal infections. The lack of an appropriate diagnostic marker may lead to the under- or mis-diagnosis of zygomycosis. Moreover, it is hard to differentiate zygomycosis from aspergillosis because the two diseases share common clinical features such as the association of sinusitis and vascular involvement. The clinically diagnostic points that discriminate zygomycosis from aspergillosis are as followed; i) ß-D-glucan is negative in zygomycosis but positive in aspergillosis; ii) diabetes is more frequent in patients with zygomycosis to those with aspergillosis; iii) the infectious lesion in aspergillosis shows an iso-low-intensity on T(2) weighted MRI image but shows a high intensity lesion in zygomycosis. The mortality rate of CNS zygomycosis is so high that an early diagnosis of it is warranted and the start appropriate anti-fungal treatments or surgical drainage in the early stage of the disease.

Inhibition of beta2-microglobulin amyloid fibril formation by alpha2-macroglobulin.

The relationship between various amyloidoses and chaperones is gathering attention. In patients with dialysis-related amyloidosis, α(2)-macroglobulin (α2M), an extracellular chaperone, forms a complex with ß(2)-microglobulin (ß2-m), a major component of amyloid fibrils, but the molecular mechanisms and biological implications of the complex formation remain unclear. Here, we found that α2M substoichiometrically inhibited the ß2-m fibril formation at a neutral pH in the presence of SDS, a model for anionic lipids. Binding analysis showed that the binding affinity between α2M and ß2-m in the presence of SDS was higher than that in the absence of SDS. Importantly, SDS dissociated tetrameric α2M into dimers with increased surface hydrophobicity. Western blot analysis revealed that both tetrameric and dimeric α2M interacted with SDS-denatured ß2-m. At a physiologically relevant acidic pH and in the presence of heparin, α2M was also dissociated into dimers, and both tetrameric and dimeric α2M interacted with ß2-m, resulting in the inhibition of fibril growth reaction. These results suggest that under conditions where native ß2-m is denatured, tetrameric α2M is also converted to dimeric form with exposed hydrophobic surfaces to favor the hydrophobic interaction with denatured ß2-m, thus dimeric α2M as well as tetrameric α2M may play an important role in controlling ß2-m amyloid fibril formation.

Critical role of interfaces and agitation on the nucleation of Abeta amyloid fibrils at low concentrations of Abeta monomers.

Amyloid deposits are pathological hallmarks of various neurodegenerative diseases including Alzheimer's disease (AD), where amyloid beta-peptide (Abeta) polymerizes into amyloid fibrils by a nucleation-dependent polymerization mechanism. The biological membranes or other interfaces as well as the convection of the extracellular fluids in the brain may influence Abeta amyloid fibril formation in vivo. Here, we examined the polymerization kinetics of 2.5, 5, 10 and 20 microM Abeta in the presence or absence of air-water interface (AWI) using fluorescence spectroscopy and fluorescence microscopy with the amyloid specific dye, thioflavin T. When the solutions were incubated with AWI and in quiescence, amyloid fibril formation was observed at all Abeta concentrations examined. In contrast, when incubated without AWI, amyloid fibril formation was observed only at higher Abeta concentrations (10 and 20 microM). Importantly, when the 5 microM Abeta solution was incubated with AWI, a ThT-reactive film was first observed at AWI without any other ThT-reactive aggregates in the bulk. When 5 microM Abeta solutions were voltexed or rotated with AWI, amyloid fibril formation was considerably accelerated, where a ThT-reactive film was first observed at AWI before ThT-reactive aggregates were observed throughout the mixture. When 5 microM Abeta solutions containing a polypropylene disc were rotated without AWI, amyloid fibril formation was also considerably accelerated, where fine ThT-reactive aggregates were first found attached at the edge of the disc. These results indicate the critical roles of interfaces and agitation for amyloid fibril formation. Furthermore, elimination of AWI may be essential for proper evaluation of the roles of various biological molecules in the amyloid formation studies in vitro.

Growth of beta(2)-microglobulin-related amyloid fibrils by non-esterified fatty acids at a neutral pH.

Abeta2M (beta(2)-microglobulin-related) amyloidosis is a frequent and serious complication in patients on long-term dialysis. Partial unfolding of beta2-m (beta(2)-microglobulin) may be essential to its assembly into Abeta2M amyloid fibrils in vivo. Although SDS around the critical micelle concentration induces partial unfolding of beta2-m to an alpha-helix-containing aggregation-prone amyloidogenic conformer and subsequent amyloid fibril formation in vitro, the biological molecules with similar activity under near-physiological conditions are still unknown. The effect of various NEFAs (non-esterified fatty acids), which are representative anionic amphipathic compounds in the circulation, on the growth of Abeta2M amyloid fibrils at a neutral pH was examined using fluorescence spectroscopy with thioflavin T, CD spectroscopy, and electron microscopy. Physiologically relevant concentrations of laurate, myristate, oleate, linoleate, and mixtures of palmitate, stearate, oleate and linoleate, induced the growth of fibrils at a neutral pH by partially unfolding the compact structure of beta2-m to an aggregation-prone amyloidogenic conformer. In the presence of human serum albumin, these NEFAs also induced the growth of fibrils when their concentrations exceeded the binding capacity of albumin, indicating that the unbound NEFAs rather than albumin-bound NEFAs induce the fibril growth reaction in vitro. These results suggest the involvement of NEFAs in the development of Abeta2M amyloidosis, and in the pathogenesis of Abeta2M amyloidosis.

Lysophospholipids induce the nucleation and extension of beta2-microglobulin-related amyloid fibrils at a neutral pH.

BACKGROUND: In beta(2)-microglobulin-related (Abeta2M) amyloidosis, partial unfolding of beta(2)-microglobulin (beta2-m) is believed to be prerequisite to its assembly into Abeta2M amyloid fibrils in vivo. Low concentrations of sodium dodecyl sulfate induce partial unfolding of beta2-m to an amyloidogenic conformer and subsequent amyloid fibril formation in vitro, but the biological molecules that induce them under near-physiological conditions have not been determined. METHODS: We investigated the effect of some lysophospholipids on the nucleation, extension and stabilization of Abeta2M amyloid fibrils at a neutral pH, using fluorescence spectroscopy with thioflavin T, circular dichroism spectroscopy and electron microscopy. We also measured plasma concentrations of lysophospholipids in 103 haemodialysis patients and 14 healthy subjects and examined the effect of uraemic and normal plasmas on the stabilization of Abeta2M amyloid fibrils at a neutral pH. RESULTS: Some lysophospholipids, especially lysophosphatidic acid (LPA), induced not only the extension of Abeta2M amyloid fibrils but also the formation of Abeta2M amyloid fibrils from the beta2-m monomer at a neutral pH, by partially unfolding the compact structure of beta2-m to an amyloidogenic conformer as well as stabilizing the extended fibrils. Haemodialysis patients had significantly higher plasma concentrations of LPA than healthy subjects. Furthermore, uraemic plasmas with the highest ranking LPA concentrations stabilized Abeta2M amyloid fibrils significantly more potently than normal plasmas. On the other hand, simple addition of LPA to normal plasma did not enhance the fibril stabilizing activity. CONCLUSIONS: These results suggest a possible role of lysophospholipids in the development of Abeta2M amyloidosis.

Procollagen C-proteinase enhancer-1 (PCPE-1) interacts with beta2-microglobulin (beta2-m) and may help initiate beta2-m amyloid fibril formation in connective tissues.

Dialysis related amyloidosis (DRA) is a progressive and serious complication in patients under long-term hemodialysis and mainly leads to osteo-articular diseases. Although beta(2)-microglobulin (beta2-m) is the major structural component of beta2-m amyloid fibrils, the initiation of amyloid formation is not clearly understood. Here, we have identified procollagen C-proteinase enhancer-1 (PCPE-1) as a new interacting protein with beta2-m by screening a human synovium cDNA library. The interaction of beta2-m with full-length PCPE-1 was confirmed by immunoprecipitation, solid-phase binding and pull-down assays. By yeast two-hybrid analysis and pull-down assay, beta2-m appeared to interact with PCPE-1 via the NTR (netrin-like) domain and not via the CUB (C1r/C1s, Uegf and BMP-1) domain region. In synovial tissues derived from hemodialysis patients with DRA, beta2-m co-localized and formed a complex with PCPE-1. beta2-m did not alter the basal activity of bone morphogenetic protein-1/procollagen C-proteinase (BMP-1/PCP) nor BMP-1/PCP activity enhanced by PCPE-1. PCPE-1 did not stimulate beta2-m amyloid fibril formation from monomeric beta2-m in vitro under acidic and neutral conditions as revealed by thioflavin T fluorescence spectroscopy and electron microscopy. Since PCPE-1 is abundantly expressed in connective tissues rich in type I collagen, it may be involved in the initial accumulation of beta2-m in selected tissues such as tendon, synovium and bone. Furthermore, since such preferential deposition of beta2-m may be linked to subsequent beta2-m amyloid fibril formation, the disruption of the interaction between beta2-m and PCPE-1 may prevent beta2-m amyloid fibril formation and therefore PCPE-1 could be a new target for the treatment of DRA.

The anti-amyloidogenic effect is exerted against Alzheimer's beta-amyloid fibrils in vitro by preferential and reversible binding of flavonoids to the amyloid fibril structure.

How various anti-amyloidogenic compounds inhibit the formation of Alzheimer's beta-amyloid fibrils (fAbeta) from amyloid beta-peptide (Abeta) and destabilize fAbeta remains poorly understood. Using spectrophotometry, spectrofluorometry, atomic force microscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and surface plasmon resonance (SPR), we investigated the anti-amyloidogenic effects of five flavonoids on fAbeta in vitro. Oxidized flavonoids generally inhibited fAbeta(1-40) formation significantly more potently than fresh compounds. Characterization of the novel fluorescence of myricetin (Myr) emitted at 575 nm with an excitation maximum at 430 nm in the presence of fAbeta(1-40) revealed the specific binding of Myr to fAbeta(1-40). By SPR analysis, distinct association and dissociation reactions of Myr with fAbeta(1-40) were observed, in contrast to the very weak binding to the Abeta monomer. A significant decrease in the rate of fibril extension was observed when >0.5 microM Myr was injected into the SPR experimental system. These findings suggest that flavonoids, especially Myr, exert an anti-amyloidogenic effect in vitro by preferentially and reversibly binding to the amyloid fibril structure of fAbeta, rather than to Abeta monomers.