Clonal characteirization of sporadic cribriform-morular variant of papillary thyroid carcinoma by laser microdissection based APC mutation analysis

Cribriform-morular variant (C-MV) of papillary thyroid carcinoma (PTC) is a rare and unusual neoplasm composed of multiple histologic components, including cribriform, papillary, solid, tall columnar, and morular patterns. Analyses of gross C-MV of PTC lesions has linked adenomatous polyposis coli (APC) mutations to its pathogenesis; however, the extent of involvement of mutations in the development Of individual components is unclear We report on bidirectional sequencing of the mutation cluster region (codons 1032-1565) of the APC gene in individually laser-microdissected components of a previously unreported C-MV of PTC. A silent Thr1493Thr gene variant was found in all tumoral components, whereas a 5-base-pair frameshift deletion at codon 1309 was identified only in the morules. Neither variant was observed in matched normal thyroid tissue. These results show the histologic components of C-MV of PTC to have some common mutational background, although additional somatic mutations may be involved in the development of morular structures.

Peptide Tyrosine Arginine, a potent immunomodulatory peptide isolated and structurally characterized from the skin secretions of the dusky gopher frog, Rana sevosa

An octadecapeptide was isolated from the skin secretions of the dusky gopher frog (Rana sevosa) on the basis of histamine release from rat peritoneal mast cells. This peptide was purified to homogeneity by HPLC and found to have the following primary structure, YLKGCWTKSYPPKPCFSR, using both Edman degradation chemistry and peptide sequencing using high-resolution mass spectrometry (Q-TOF MS). The peptide, named peptide Tyrosine Arginine (pYR) shares 77.8% homology with peptide Leucine Arginine (pLR). The effects of the natural amidated peptide, non-amidated peptide and C-loop region of pYR on granulopoiesis and neutrophil apoptosis were investigated. All three analogues inhibited the early development of granulocyte macrophage colonies from bone marrow stem cells but did not induce apoptosis of the end stage granulocytes, the mature neutrophil. Thus, pYR is a novel member of an important and emerging new class of amphibian peptides with hemopoietic actions. (c) 2004 Elsevier Inc. All rights reserved.

Glucose lowers the threshold for human aortic vascular smooth muscle cell migration: inhibition by protein phosphatase-2A

AIMS/HYPOTHESIS: Atherosclerosis, which occurs prematurely in individuals with diabetes, incorporates vascular smooth muscle cell (VSMC) chemotaxis. Glucose, through protein kinase C-beta(II) signalling, increases chemotaxis to low concentrations of platelet-derived growth factor (PDGF)-BB. In VSMC, a biphasic response in PDGF-beta receptor (PDGF-betaR) level occurs as PDGF-BB concentrations increase. The purpose of this study was to determine whether increased concentrations of PDGF-BB and raised glucose level had a modulatory effect on the mitogen-activated protein kinase/extracellular-regulated protein kinase pathway, control of PDGF-betaR level and chemotaxis.

METHODS: Cultured aortic VSMC, exposed to normal glucose (NG) (5 mmol/l) or high glucose (HG) (25 mmol/l) in the presence of PDGF-BB, were assessed for migration (chemotaxis chamber) or else extracted and immunoblotted.

RESULTS: At concentrations of PDGF-BB <540 pmol/l, HG caused an increase in the level of PDGF-betaR in VSMC (immunoblotting) versus NG, an effect that was abrogated by inhibition of aldose reductase or protein kinase C-beta(II). At higher concentrations of PDGF-BB (>540 pmol/l) in HG, receptor level was reduced but in the presence of aldose reductase or protein kinase C-beta(II) inhibitors the receptor levels increased. It is known that phosphatases may be activated at high concentrations of growth factors. At high concentrations of PDGF-BB, the protein phosphatase (PP)2A inhibitor, endothall, caused an increase in PDGF-betaR levels and a loss of biphasicity in receptor levels in HG. At higher concentrations of PDGF-BB in HG, the chemoattractant effect of PDGF-BB was lost (chemotaxis chamber). Under these conditions inhibition of PP2A was associated with a restoration of chemotaxis to high concentrations of PDGF-BB.

CONCLUSION/INTERPRETATION: The biphasic response in PDGF-betaR level and in chemotaxis to PDGF-BB in HG is due to PP2A activation.

Changes in muscle sympathetic nerve activity and vascular responses evoked in the spinotrapezius muscle of the rat by systemic hypoxia.

Responses evoked in muscle sympathetic nerve activity (MSNA) by systemic hypoxia have received relatively little attention. Moreover, MSNA is generally identified from firing characteristics in fibres supplying whole limbs: their actual destination is not determined. We aimed to address these limitations by using a novel preparation of spinotrapezius muscle in anaesthetised rats. By using focal recording electrodes, multi-unit and discriminated single unit activity were recorded from the surface of arterial vessels. This had cardiac- and respiratory-related activities expected of MSNA, and was increased by baroreceptor unloading, decreased by baroreceptor stimulation and abolished by autonomic ganglion blockade. Progressive, graded hypoxia (breathing sequentially 12, 10, 8% O2 for 2 min each) evoked graded increases in MSNA. In single units, mean firing frequency increased from 0.2 ± 0.04 in 21% O2 to 0.62 ± 0.14 Hz in 8% O2, while instantaneous frequencies ranged from 0.04–6 Hz in 21% O2 to 0.09–20 Hz in 8% O2. Concomitantly, arterial pressure (ABP), fell and heart rate (HR) and respiratory frequency (RF) increased progressively, while spinotrapezius vascular resistance (SVR) decreased (Spinotrapezius blood flow/ABP), indicating muscle vasodilatation. During 8% O2 for 10 min, the falls in ABP and SVR were maintained, but RF, HR and MSNA waned towards baselines from the second to the tenth minute. Thus, we directly show that MSNA increases during systemic hypoxia to an extent that is mainly determined by the increases in peripheral chemoreceptor stimulation and respiratory drive, but its vasoconstrictor effects on muscle vasculature are largely blunted by local dilator influences, despite high instantaneous frequencies in single fibres.

Molecular characterization and phylogenetic analysis of quinolone resistance-determining regions (QRDRs) of gyrA, gyrB, parC and parE gene loci in viridans group streptococci isolated from adult patients with cystic fibrosis

This study demonstrated key resistance genes to fluroquinilones in Streptococcci isolated from sputum of people with CF. This suggests that other bacteria which are sometimes considered commensal may be a resovoir for resistance. Jse designed the study with Moore.