Novel, potent small-molecule inhibitors of the molecular chaperone Hsp90 discovered through structure-based design

The crystal structure of a previously reported screening hit 1 (CCT018159) bound to the N terminal domain of molecular chaperone Hsp90 has been used to design 5-amide analogues. These exhibit enhanced potency against the target in binding and functional assays with accompanying appropriate cellular pharmacodynamic changes. Compound 11 (VER-49009) compares favorably with the clinically evaluated 17-AAG.     

Biofilm-specific surface properties and protein expression in oral Streptococcus sanguis

OBJECTIVE: Oral streptococci are primary colonisers of the tooth surface and are abundant in dental plaque biofilms. Bacteria growing in these relatively dense, surface-associated communities are phenotypically quite distinct from their planktonic counterparts. The purpose of the present study was to develop a method to investigate biofilm-specific surface protein expression by Streptococcus sanguis to help provide a better understanding of the critical events in plaque development. DESIGN: Biofilm cells were grown on the surface of glass beads in a biofilm device fed with mucin-containing artificial saliva. Planktonic cells were grown in continuous culture at approximately the same growth rate. Surface hydrophobicity of biofilm and planktonic cells was determined by hexadecane partitioning, and expression of streptococcal fibronectin adhesin CshA was determined in ELISA using specific antiserum. Antisera raised to glutaraldehyde-fixed whole biofilm or planktonic grown cells were used to screen an expression library of S. sanguis genomic DNA, and isolated clones were sequenced. RESULTS: Phenotypic analysis of biofilm and planktonic cells confirmed that mode of growth affected surface properties of S. sanguis. Thus, hydrophobicity and CshA expression was significantly elevated in biofilm cells. Library screening with biofilm antiserum yielded 32 recombinant clones representing 21 different S. sanguis proteins involved in adhesion and colonisation, carbohydrate utilisation or bacterial metabolism. In differential analysis of four selected Escherichia coli clones, biofilm antiserum reacted five times stronger than planktonic antiserum with cell-free extracts of clones encoding homologues of CshA and Cna collagen adhesin of Staphylococcus aureus, suggesting that these surface proteins are up-regulated in biofilm cells. In contrast, both antisera reacted equally strongly with cell-free extracts of the remaining two clones (encoding dihydrofolate synthase and an unknown protein). CONCLUSIONS: The method described represents a useful means for determining bacterial protein expression in biofilms based on a combination of molecular and immunological techniques. Surface expression of putative fibronectin and collagen adhesins was up-regulated in biofilm cells.     

Cultural consistency in Australian dental students from two different ethnic backgrounds

The objective of this study was to examine the value orientations of dental students from different ethnic backgrounds studying in Australian dental schools. A ninety-eight-item questionnaire was used to collect the data, including fifteen subscales developed consistent with the Kluckhohn and Strodtbeck value orientation model. To compare the value orientation structure and to determine if any ethnic differences existed, a multivariate analysis of variance called profile analysis was performed on the fifteen value subscales. Of the 401 participants, 30.2 percent were Anglo-Australian and 44.9 percent were Asian. The remainder (24.9 percent) were "Other-background residents" or "Other-international students." This article presents data from Asian (n=184) and Anglo-Australian (n=124) background respondents. Mean age was 21.7 years (s.e. 0.35 years) among Anglo-Australian and 20.8 years (s.e. 0.17 years) among Asians. Asians born overseas represented 70.7 percent (n=130) of this group. Of Australia-born Asians (n=54), 90.6 percent were first-generation Australians. When comparing their value profile, we found a significant association between ethnicity and value orientation profile scores (p<0.05). Despite the significant overall result, the strength of the association (eta(2)=0.007) indicated that this effect was trivial relative to the unexplained variance in value orientation. The findings suggest that, behind an apparent ethnic diversity, a single distinctive value profile might exist to which the majority of dental students subscribe.     

Cognitive processing in monozygotic twins discordant for chronic fatigue syndrome

Twenty-one pairs of monozygotic twins discordant for chronic fatigue syndrome (CFS) and 21 matched healthy control (HC) subjects were assessed with 5 untimed tests and 5 timed tests from the computer-based NeuroCognitive Assessment Battery (R. K. Mahurin, 1993). Random effects regression showed no difference between CFS and healthy twins on any of the cognitive tests. Further, the twin groups did not differ from the HC group on any content-dependent measure. In contrast, both sets of twins performed worse than the HC group on all speed-dependent tests except Finger Tapping. Self-rated fatigue and dysphoric mood were only weakly correlated with cognitive performance. These data point toward a shared genetic trait related to information processing that is manifest in the CFS context. The findings have implications for differentiating genetic and acquired vulnerability in the symptomatic expression of the disorder. ((c) 2004 APA, all rights reserved)     

Mycotic coronary artery aneurysm detected by gallium67 scintigraphy

A 71-year-old man presented with fever and positive blood cultures for methicillin-sensitive Staphylococcus aureus 4 days after an uncomplicated intra-luminal abdominal aortic aneurysm repair. Investigations looking for a source of sepsis including computerized tomography scans, transoesophageal echocardiography, a bone scan and repeated chest X-rays, did not reveal an infective focus. Gallium(67) scintigraphy, however, showed a focus of tracer uptake in the region of the aorto-cardiac junction consistent with the presence of an abscess. Coronary angiography later opacified an aneurysmal cavity arising from the right sinus of Valsalva which was confirmed to be a mycotic aneurysm on thoracotomy. This is a rare case of early detection of a cardiac mycotic aneurysm by Gallium(67) scintigraphy.     

Hemicrania continua: a third case in which attacks alternate sides

Hemicrania continua (HC) is an uncommon, primary headache disorder characterized by a continuous unilateral headache of moderate intensity with superimposed exacerbations of more severe pain. HC exists in two temporal subtypes, a continuous form in which headaches persist continuously without remission periods, and a less common remitting form in which bouts of continuous headaches are separated by pain-free remissions. There have been more than 100 prior reports of HC; in the majority of which the headache is strictly unilateral and without side shift. We now report the third patient in whom headaches alternated sides during different attacks.     

Modulation of inflammation and response to dexamethasone by Annexin 1 in antigen-induced arthritis

OBJECTIVE: Annexin 1 (Anx-1) is a putative mediator of the antiinflammatory actions of glucocorticoids (GCs). This study investigated the role of Anx-1 in experimental arthritis and in GC-mediated inhibition of inflammation, using antigen-induced arthritis (AIA) in Anx-1 knockout (Anx-1(-/-)) mice. METHODS: Arthritis was induced by intraarticular injection of methylated BSA (mBSA) in mice preimmunized with mBSA. Disease was assessed after 7 days by histologic examination of the knee joints. Serum levels of anti-mBSA IgG were determined by enzyme-linked immunosorbent assay. Cytokine messenger RNA (mRNA) expression was detected by real-time polymerase chain reaction. RESULTS: A significant exacerbation of arthritis was observed in the Anx-1(-/-) mice compared with wild-type (WT) mice. This was associated with increased mRNA expression of synovial interleukin-1 beta, tumor necrosis factor alpha, interleukin-6, and macrophage migration inhibitory factor. Dexamethasone significantly reduced the histologic severity of synovitis and bone damage in the WT mice, but exerted no inhibitory effects in the Anx-1(-/-) mice, and also significantly reduced the serum levels of anti-mBSA IgG and the numbers of peripheral blood neutrophils and lymphocytes in WT mice, but had no such effect in Anx-1(-/-) mice. CONCLUSION: Anx-1 exerts endogenous antiinflammatory effects on AIA via the regulation of cytokine gene expression, and also mediates the antiinflammatory actions of dexamethasone in AIA.     

Control of late off-center cone bipolar cell differentiation and visual signaling by the homeobox gene Vsx1

Retinal bipolar cells are interneurons that transmit visual signals from photoreceptors to ganglion cells. Although the visual pathways mediated by bipolar cells have been well characterized, the genes that regulate their development and function are largely unknown. To determine the role in bipolar cell development of the homeobox gene Vsx1, whose retinal expression is restricted to a major subset of differentiating and mature cone bipolar (CB) cells, we targeted the gene in mice. Bipolar cell fate was not altered in the absence of Vsx1 function, because the pan-bipolar markers Chx10 and Ret-B1 continued to be expressed in inner nuclear layer neurons labeled by the Vsx1-targeting reporter gene, tauLacZ. The specification, number, and gross morphology of the subset of on-center and off-center (OFF)-CB cells defined by tauLacZ expression from the Vsx1 locus were also normal in Vsx1(tauLacZ)/Vsx1(tauLacZ) mice. However, the terminal differentiation of OFF-CB cells in the retina of Vsx1(tauLacZ)/Vsx1(tauLacZ) mice was incomplete, as demonstrated by a substantial reduction in the expression of at least four markers (recoverin, NK3R, Neto1, and CaB5) for these interneurons. These molecular abnormalities were associated with defects in retinal function and documented by electroretinography and in vitro ganglion cell recordings specific to cone visual signaling. In particular, there was a general reduction in the light-mediated activity of OFF, but not on-center, ganglion cells. Thus, Vsx1 is required for the late differentiation and function of OFF-CB cells and is associated with a heritable OFF visual pathway-specific retinal defect.     

Mucin-rich variant of salivary duct carcinoma: a clinicopathologic and immunohistochemical study of four cases

Salivary duct carcinoma is a relatively uncommon aggressive neoplasm, typically found in the parotid glands of older men. The histologic appearance is that of an in situ and invasive high-grade adenocarcinoma, and it closely resembles ductal carcinoma of the breast. Several variants of the latter are very well known, but only papillary, sarcomatoid, and low-grade subtypes have so far been reported in salivary duct carcinoma. This study describes the clinicopathologic and immunohistochemical findings in four examples of an additional previously undescribed variant, rich in mucin. Each tumor showed areas of typical salivary duct carcinoma, but in addition there were lakes of epithelial mucin-containing malignant cells, i.e., mucinous (colloid) carcinoma. All four tumors expressed androgen receptors, cytokeratins, epithelial membrane antigen, gross cystic disease fluid protein-15, and carcinoembryonic antigen, but S-100 protein, other myoepithelial markers, and estrogen and progesterone receptors were negative. The mucin antigen profile showed positivity for MUC2, MUC5B, and MUC6 in all cases but only rare staining with MUC5AC and MUC7. Strong immunohistochemical overexpression of HER2/neu was demonstrated in one tumor, together with amplification by fluorescence in situ hybridization; another case was weakly positive with just one antiserum, but the remaining two tumors were completely negative. Small quantities of mucin have often been described in salivary duct carcinoma but not large extracellular mucinous lakes, which though prominent in the present series, were not as extensive as in mucinous adenocarcinoma. The relatively poor clinical outcome of the patients in our study mirrored that seen in usual-type salivary duct carcinoma and emphasizes the importance of differentiating mucin-rich salivary duct carcinoma from pure mucinous (colloid) adenocarcinoma, a tumor not fully defined, but possibly with a better prognosis.     

Comparison of apparent efficiency of haemodialysis satellite units in England and Wales using data envelopment analysis

OBJECTIVES: To expand care for chronic haemodialysis (HD) patients throughout England and Wales by studying two aspects of service delivery that are important: to identify relative performance of haemodialysis satellite units (HDSUs), and understand the factors that influence the performance. As a first step toward these aspects, this work reports a study of apparent comparative efficiency in the delivery of HDSUs and demonstrates the potential of data envelopment analysis (DEA). METHODS: DEA was applied to data obtained from a national survey of the organizational structures and processes of delivering care at HDSUs in England and Wales. RESULTS: DEA was found to be a judicious approach for performance assessment of HDSUs, although valid results depend on appropriate model specification and quality of data available. The available data were not of sufficient comprehensiveness or quality to produce definitive results but suggested that overall efficiency could improve; these data suggested by as much as 10% overall (mean efficiency score 90%) and variably within the sample (46 [65%] that HDSUs were potentially inefficient, the lowest unit scoring 38%). CONCLUSIONS: Addressing questions raised by comparative inefficiency could help plans to improve capacity to deal with the growing demand for HD delivered in HDSUs. The application was an important start and needs to be followed by further research to establish model validity and obtain authoritative results.