Perfect imaging, epsilon-near zero phenomena and waveguiding in the scope of nonlocal effects

Plasmons in metals can oscillate on a sub-wavelength length scale and this large-k response constitutes an inherent prerequisite for fascinating effects such as perfect imaging and intriguing wave phenomena associated with the epsilon-near-zero (ENZ) regime. While there is no upper cut-off within the local-response approximation (LRA) of the plasma polarization, nonlocal dynamics suppress response beyond ω/v(F), where v(F) is the Fermi velocity of the electron gas. Nonlocal response has previously been found to pose limitations to field-enhancement phenomena. Accounting for nonlocal hydrodynamic response, we show that perfect imaging is surprisingly only marginally affected by nonlocal properties of a metal slab, even for a deep subwavelength case and an extremely thin film. Similarly, for the ENZ response we find no indications of nonlocal response jeopardizing the basic behaviors anticipated from the LRA. Finally, our study of waveguiding of gap plasmons even shows a positive nonlocal influence on the propagation length.

Tunable acoustic double negativity metamaterial

Man-made composite materials called “metamaterials” allow for the creation of unusual wave propagation behavior. Acoustic and elastic metamaterials in particular, can pave the way for the full control of sound in realizing cloaks of invisibility, perfect lenses and much more. In this work we design acousto-elastic surface modes that are similar to surface plasmons in metals and on highly conducting surfaces perforated by holes. We combine a structure hosting these modes together with a gap material supporting negative modulus and collectively producing negative dispersion. By analytical techniques and full-wave simulations we attribute the observed behavior to the mass density and bulk modulus being simultaneously negative.

Epidemiology of methicillin-resistant Staphylococcus aureus carrying the novel mecC gene in Denmark corroborates a zoonotic reservoir with transmission to humans

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated (HA), community-associated (CA) and livestock-associated (LA) infections. Recently, the discovery of human and bovine MRSA isolates carrying a new mecA gene homologue, mecA(LGA251) (now designated mecC), has caused concern because they are not detected by conventional, confirmatory tests for MRSA. Very little is known about their frequency, epidemiology and possible transmission between livestock and humans. In this study, the epidemiology of the mecC isolates in Denmark was investigated by screening the national collections of MRSA cases (from 1988 onwards) and S. aureus bacteraemia cases (from 1958 onwards). Isolates carrying mecC were only recovered infrequently before 2003 (n = 2) but now seem to be increasing, with 110 cases in 2003-2011. Clinical data on mecC-carrying MRSA demonstrated that mecC-MRSA were primarily community-acquired (CA-MRSA) and affected persons typically living in rural areas, being older than other CA-MRSA patients. Among 22 cases in Region Zealand, four reported contact with cattle and sheep. Two of these persons lived on farms with livestock positive for mecC-carrying MRSA, sharing spa type (t843), MLVA (MT429) and PFGE pattern with the human isolates. These observations indicate that mecC-carrying MRSA can be exchanged between humans and ruminants.

Influence of cone beam CT on treatment plan before surgical intervention of mandibular third molars and impact of radiographic factors on deciding on coronectomy vs surgical removal

OBJECTIVES

To assess the influence of cone beam CT (CBCT) on treatment plan before surgical intervention of mandibular third molars and to identify radiographic factors with an impact on deciding on coronectomy.

METHODS

186 mandibular third molars with an indication for surgical intervention underwent a radiographic examination with two methods: (1) panoramic imaging in combination with stereo-scanography and (2) CBCT. After the radiographic examination a treatment plan (TP) was established: either surgical removal (Sr) or coronectomy (Co). The first TP was based on the panoramic image and stereo-scanogram, while the second TP was established after CBCT was available. Logistic regression analyses were used to identify factors predisposing for Co after CBCT.

RESULTS

Treatment was performed according to the second TP. Agreement between the first and second TP was seen in 164 cases (88%), while the TP changed for 22 teeth (12%) after CBCT. Direct contact between the third molar and the mandibular canal had the highest impact on deciding on Co [odds ratio (OR) = 101.8, p < 0.001]. Direct contact was not a sufficient factor, however; thus, lumen narrowing of the canal (OR = 38.9-147.2, p < 0.001) and canal positioned in a bending or a groove in the root complex (OR = 32.8, p = 0.016) were additional canal-related factors for deciding on Co.

CONCLUSION

CBCT influenced the treatment plan for 12%. Direct contact in combination with narrowing of the canal lumen and canal positioned in a bending or a groove in the root complex observed in CBCT images were significant factors for deciding on coronectomy.

A reverse J-shaped association of all-cause mortality with serum 25-hydroxyvitamin D in general practice: the CopD study

CONTEXT

Optimal levels of vitamin D have been a topic of heavy debate, and the correlation between 25-hydroxyvitamin D [25(OH)D] levels and mortality still remains to be established.

OBJECTIVE

The aim of the study was to determine the association between all-cause mortality and serum levels of 25(OH)D, calcium, and PTH.

DESIGN AND SETTING

We conducted a retrospective, observational cohort study, the CopD Study, in a single laboratory center in Copenhagen, Denmark.

PARTICIPANTS

Serum 25(OH)D was analyzed from 247,574 subjects from the Copenhagen general practice sector. In addition, serum levels of calcium, albumin-adjusted calcium, PTH, and creatinine were measured in 111,536; 20,512; 34,996; and 189,496 of the subjects, respectively.

MAIN OUTCOME MEASURES

Multivariate Cox regression analysis was used to compute hazard ratios for all-cause mortality.

RESULTS

During follow-up (median, 3.07 yr), 15,198 (6.1%) subjects died. A reverse J-shaped association between serum level of 25(OH)D and mortality was observed. A serum 25(OH)D level of 50-60 nmol/liter was associated with the lowest mortality risk. Compared to 50 nmol/liter, the hazard ratios (95% confidence intervals) of all-cause mortality at very low (10 nmol/liter) and high (140 nmol/liter) serum levels of 25(OH)D were 2.13 (2.02-2.24) and 1.42 (1.31-1.53), respectively. Similarly, both high and low levels of albumin-adjusted serum calcium and serum PTH were associated with an increased mortality, and secondary hyperparathyroidism was associated with higher mortality (P < 0.0001).

CONCLUSION

In this study from the general practice sector, a reverse J-shaped relation between the serum level of 25(OH)D and all-cause mortality was observed, indicating not only a lower limit but also an upper limit. The lowest mortality risk was at 50-60 nmol/liter. The study did not allow inference of causality, and further studies are needed to elucidate a possible causal relationship between 25(OH)D levels, especially higher levels, and mortality.

Detection of cavitated approximal surfaces using cone beam CT and intraoral receptors

OBJECTIVES

The aim of this study was to compare cone beam CT (CBCT) in a small field of view (FOV) with a solid-state sensor and a photostimulable phosphor plate system for detection of cavitated approximal surfaces.

METHODS

257 non-filled approximal surfaces from human permanent premolars and molars were recorded by two intraoral digital receptors, a storage phosphor plate (Digora Optime, Soredex) and a solid-state CMOS sensor (Digora Toto, Soredex), and scanned in a cone beam CT unit (3D Accuitomo FPD80, Morita) with a FOV of 4 cm and a voxel size of 0.08 mm. Image sections were carried out in the axial and mesiodistal tooth planes. Six observers recorded surface cavitation in all images. Validation of the true absence or presence of surface cavitation was performed by inspecting the surfaces under strong light with the naked eye. Differences in sensitivity, specificity and agreement were estimated by analysing the binary data in a generalized linear model using an identity link function.

RESULTS

A significantly higher sensitivity was obtained by all observers with CBCT (p < 0.001), which was not compromised by a lower specificity. Therefore, a significantly higher overall agreement was obtained with CBCT (p < 0.001). There were no significant differences between the Digora Optime phosphor plate system and the Digora Toto CMOS sensor for any parameter.

CONCLUSIONS

CBCT was much more accurate in the detection of surface cavitation in approximal surfaces than intraoral receptors. The differences are interpreted as clinically significant. A CBCT examination performed for other reasons should also be assessed for approximal surface cavities in teeth without restorations.

Cone beam CT image artefacts related to head motion simulated by a robot skull: visual characteristics and impact on image quality

OBJECTIVES

The aim of this study was to assess artefacts and their impact on cone beam CT (CBCT) image quality (IQ) after head motion simulated by a robot skull.

METHODS

A fully dentate human skull incorporated into a robot simulated pre-determined patient movements. Ten head motion patterns were selected based on the movement of the C-arm of the CBCT units (no motion as reference). Three CBCT units were used [a three-dimensional eXam (K) (KaVo Dental GmbH, Biberach, Germany), a Promax 3D MAX (P) (Planmeca Oy, Helsinki, Finland) and a Scanora(®) 3D (S) (Soredex Oy, Tuusula, Finland)]. Axial images were qualitatively assessed at three levels: mental foramen (MF), infraorbital foramen and supraorbital foramen, and artefacts characterized as stripe-like, double contours, unsharpness or ring-like. A 100 mm visual analogue scale (VAS) was used to quantitatively assess IQ. Cross-sectional images of the lower third molar and MF bilaterally were also evaluated by VAS. Four blinded examiners assessed the images.

RESULTS

For all units and motion patterns, stripe-like artefacts were the most common. The four observers agreed on the presence of at least one artefact type in 90% of the images. Axial images showed lower overall IQ after motion (VAS = 72.4 ± 24.0 mm) than reference images (VAS = 97.3 ± 2.6 mm). The most severe artefacts were seen at the MF level. For cross-sectional images, IQ was lowest after tremor. The mean IQ range was 74-89 and 57-90 for isolated (tilting, rotation and nodding) and combined (nodding + tilting and rotation + tilting) movements, respectively. IQ for MF was lower than for third molar for any movement except tremor.

CONCLUSIONS

Head motion of any type resulted in artefacts in CBCT images. The impact on IQ depended on the region and level in the skull.

Thermography as a quantitative imaging method for assessing postoperative inflammation

OBJECTIVE

To assess differences in skin temperature between the operated and control side of the face after mandibular third molar surgery using thermography.

METHODS

127 patients had 1 mandibular third molar removed. Before the surgery, standardized thermograms were taken of both sides of the patient's face using a Flir ThermaCam™ E320 (Precisions Teknik AB, Halmstad, Sweden). The imaging procedure was repeated 2 days and 7 days after surgery. A region of interest including the third molar region was marked on each image. The mean temperature within each region of interest was calculated. The difference between sides and over time were assessed using paired t-tests.

RESULTS

No significant difference was found between the operated side and the control side either before or 7 days after surgery (p > 0.3). The temperature of the operated side (mean: 32.39 °C, range: 28.9-35.3 °C) was higher than that of the control side (mean: 32.06 °C, range: 28.5-35.0 °C) 2 days after surgery [0.33 °C, 95% confidence interval (CI): 0.22-0.44 °C, p < 0.001]. No significant difference was found between the pre-operative and the 7-day post-operative temperature (p > 0.1). After 2 days, the operated side was not significantly different from the temperature pre-operatively (p = 0.12), whereas the control side had a lower temperature (0.57 °C, 95% CI: 0.29-0.86 °C, p < 0.001).

CONCLUSIONS

Thermography seems useful for quantitative assessment of inflammation between the intervention side and the control side after surgical removal of mandibular third molars. However, thermography cannot be used to assess absolute temperature changes due to normal variations in skin temperature over time.

Thermographic imaging of facial skin--gender differences and temperature changes over time in healthy subjects

OBJECTIVES

To assess changes in facial skin temperature over time, to identify sources of variation related to skin temperature and to evaluate interobserver reproducibility in measurements of the thermograms.

METHODS

62 volunteers (32 females, 30 males, mean age 23.4, range 19.5-29.5 years) underwent thermography of the face (left and right side lateral images) on four occasions with approximately 2 months between each session. Three observers recorded the images and marked regions of interest (ROIs) in each image using dedicated software. Smoking, exercise habits and use of oral contraceptives were recorded.

RESULTS

A significant difference between sessions (≤1 °C, p<0.001) and between observers (≤0.11 °C, p<0.001) was identified. The difference between sides was not significant (≤0.07 °C, p=0.7). None of the interactions between side, session and observer were significant. Smoking, exercise habits and oral contraceptive intake were not significant impact factors when included as covariates in the analysis (p>0.1). ROI temperature was significantly higher in males than in females (0.7 °C, p<0.001). A mixed model analysis of variance showed that observer had little impact on the expected standard deviation, whereas session and subject had a greater impact.

CONCLUSIONS

Face temperature is symmetrical and varies over time. The non-significant difference between sides is highly reproducible, even between observers.

P1-17-06: A Phase II Trial of the CDK 4/6 Inhibitor PD0332991 in Women with Advanced Breast Cancer

Background: Dysregulation of the G1/S checkpoint of the cell cycle is a feature of many breast cancers. PD0332991, a potent oral inhibitor of cyclin-dependent kinases (CDKs) 4 and 6 is well-tolerated and has demonstrated activity in a phase I trial in a variety of solid tumors at a phase II dose of 125 mg daily on a 3 week on/1 week off schedule. Preclinical data suggest that this agent is most active in ER+ (luminal) breast cancers. We are performing a phase II study of PD0332991 in women with advanced breast cancer, one of several parallel disease cohorts under study.

Methods: Patients with histologically-confirmed stage IV breast cancer were eligible if they had primary or metastatic tumor which stained positive for retinoblastoma (Rb) protein by immunohistochemistry, disease measureable by RECIST criteria and adequate organ function/performance status. Treatment was initiated with PD0332991 at 125 mg orally, days 1 - 21 of a 28-day treatment cycle. Tumor assessments occurred after every 2 cycles (8-week intervals). The primary objective was to determine the safety and response rates in cohorts of 15 patients per tumor type; 15 patients per arm provided 80% power to detect a 15% (1/15) response rate per disease that would lead to further cohort expansion. Secondary objectives include PK, PD and predictive biomarker assessment.

Results: 36 patients were screened, 32 (89%) stained positive for Rb, and 14 have enrolled on study. The only reported toxicites are neutropenia (7 patients, 4 grade 3/4), thrombocytopenia (1 patient, grade 1) and fatigue (1 patient, grade 2). 3 patients (23%) have had dose interruptions and 5 (38%) have had dose-reduction for neutropenia, though no episodes of febrile neutropenia have occurred. Among 11 patients assessable for response to date, there is 1(7%) partial response (PR), 6 (43%) with stable disease (SD) and 4 (29%) with progressive disease (PD). 3 of 6 patients with stable disease have received greater than 6 months of therapy, and these sustained responses have occurred with dosing as low as 50 mg/day. All PR/SD have occurred in patients with ER+ tumors; all PD have been in patients with triple negative (ER-/PR-/Her2-) disease. The cyclin D1 status of all patients are being assessed. Of the 10 ER+ patients, 3 are cyclin D1 amplified, 5 are non-amplified and 2 are pending assessment. 2 in 4 cyclin D1 non-amplified patients had SD, while 2 of 2 evaluable patients with amplification had SD. PK and PD analyses are in progress.

Conclusions: PD 0332991 is an extremely well-tolerated, oral CDK 4/6 inhibitor that demonstrates prolonged single-agent activity in ER+ breast cancer patients who have progressed on hormonal therapy. These data have prompted expansion of this breast cancer cohort to further delineate activity and translational studies examining predictors of response are underway.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-17-06.

Accuracy of scanography using storage phosphor plate systems and film for assessment of mandibular third molars

OBJECTIVES

The aim of this study was to compare the diagnostic accuracy of two digital photostimulable storage phosphor (PSP) systems and film for assessment of mandibular third molars before surgery.

METHODS

110 patients were referred to have both their mandibular third molars removed. Each patient underwent a radiographic examination with scanography using either Digora (Soredex, Helsinki, Finland) and film or VistaScan (Dürr Dental, Beitigheim-Bissingen, Germany) and film in a randomized paired design. Two observers examined the following variables on the scanograms: bone coverage, angulation of the tooth in the bone, number of roots, root morphology and the relationship to the mandibular canal. In 75 of the pairs (Digora/film pair = 38 and Vista/film pair = 37) both third molars were eventually removed. During and after surgery the same variables were assessed, which served as reference standard for the radiographic assessments. The Wilcoxon signed-rank test tested differences in accuracy (radiographic compared with surgical findings) between Digora/film and between Vista/film.

RESULTS

There was no statistically significant difference between the diagnostic accuracy of film and either of the two digital receptors for assessment of mandibular third molars before surgery (P > 0.05), although Digora obtained a higher accuracy than film.

CONCLUSIONS

Scanography is a valuable method for examination of mandibular third molars before removal and the PSP digital receptors in this study were equal to film for this purpose.

NIPA1 mutation in complex hereditary spastic paraplegia with epilepsy

BACKGROUND AND PURPOSE

  Hereditary spastic paraplegia (HSP) is a group of clinically and genetically heterogeneous neurodegenerative disorders characterized in the 'pure' phenotype by progressive spasticity and weakness of the lower limbs. In the 'complex' phenotype, additional neurologic symptoms or signs are found. Mutations in the NIPA1 gene have been reported to cause spastic paraplegia type 6 (SPG6) in 10 families. SPG6 is a rare form of autosomal dominantly inherited HSP associated with a pure phenotype; however, in one complex SPG6 family, idiopathic generalized epilepsy (IGE) has been described and in addition, recurrent microdeletions at 15q11.2 including NIPA1 have been identified in patients with IGE. The purpose was to identify NIPA1 mutations in patients with pure and complex HSP.

METHODS

  Fifty-two patients with HSP were screened for mutations in NIPA1.

RESULTS

  One previously reported missense mutation c.316G>A, p.Gly106Arg, was identified in a complex HSP patient with spastic dysarthria, facial dystonia, atrophy of the small hand muscles, upper limb spasticity, and presumably IGE. The epilepsy co-segregated with HSP in the family.

CONCLUSION

  NIPA1 mutations were rare in our population of patients with HSP, but can be found in patients with complex HSP. Epilepsy might be more common in SPG6 than in other forms of HSP because of a genetic risk factor closely linked to NIPA1.

Abstract P6-15-13: Biologic Activity of a Novel Heat Shock Protein 90 Inhibitor, PF-4928473, in Human Breast Cancer Cell Lines

Background: Heat shock protein 90 (HSP90) is a key molecular chaperone involved with the post-translational folding and maturation of various cellular proteins, including Raf, Src, ER, EGFR, HER2/ErbB2, IGFR, and VEGFR. Therefore, targeting HSP90 represents an attractive strategy for modulating aberrant oncogenic signal transduction in human malignancies. In the present study, we investigate the anti-cancer activity of PF-4928473, a novel small molecule inhibitor of HSP90, in a diverse panel of human breast cancer cell lines in vitro.

Methods: 49 breast cancer cell lines (representing 10 luminal, 18 HER2- amplified, 18 non-luminal, 3 immortalized subtypes), including two HER2- amplified lines with conditioned trastuzumab and lapatinib resistance (SKBR3 parental), were assessed. Cell proliferation assays with two-fold drug dilutions over 9 concentrations were performed over 6 days to determine growth-adjusted IC50 and IC100 values, the latter as a surrogate of in vitro drug lethality. Flow-cytometry was performed in a selected subset of 21 cell lines to assess effects on cell cycle and apoptosis after 48 hours and 5 days of drug exposure, respectively. Western blot analysis evaluated the biochemical effects of HSP90 drug inhibition. Results: In our panel, IC50s ranged from 8 (±1) nM to 525 (±2) nM, with 45 cell lines exhibiting IC50s ≥50 nM. Differential drug sensitivity was observed with HER2-amplified lines, with 15 of 18 demonstrating IC50s ≥28 nM. For SKBR3-trastuzumab and -lapatinib-resistant lines, IC50s were 13 (±1) nM and 21 (±2) nM, respectively. IC100s ranged from 9 (±3) nM to &gt; 1000 nM. 17 of 18 HER2-amplified lines had IC100s between 9 (±3) nM and 69 (±1) nM, including SKBR3-trastuzumab and -lapatinib-resistant lines at 31 (±2) nM and 66 (±2) nM, respectively. Flow cytometry with 50 nM of PF-4928473 revealed moderate early apoptotic effects in cell lines with IC50s &lt; 30 nM, encompassing the majority of HER2-amplified lines. Mild effects on cell cycle, primarily G0/G1 arrest, were observed in 8 lines at 50 and/or 100 nM. Western blots of representative cell lines at 50 and 100 nM of PF-4928473 identified downregulation of p-AKT and p-ERK in the HER2-amplified SKBR3 line (IC50: 19 ±4 nM), vs. relative lack of effect for the non-luminal MDA-MB-468 (IC50: 24 ±5 nM) and luminal KPL-1 (IC50: 68 ±2 nM) lines. Upregulation of HSP70, a known biomarker associated with HSP90 inhibition, was observed at 12 hours post-drug exposure regardless of cell sensitivity. Further biochemical studies are ongoing.

Conclusions: PF-4928473 demonstrated low nanomolar in vitro anti-proliferative activity, lethality, and apoptosis in a wide panel of human breast cancer cell lines, including trastuzumab and lapatinib-resistant lines. Biological effects were most pronounced in HER2-amplified lines, in keeping with HER2 as a known protein client of HSP90. Based on these results, further translational evaluation of HSP90 inhibitors in this population merits consideration.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-15-13.

Intake of wholegrain products and risk of colorectal cancers in the Diet, Cancer and Health cohort study

Background:

Consumption of wholegrain (WG) products may protect against colon and rectal cancer.

Methods:

The associations between total and individual WG product consumption and colon and rectal cancer risk were prospectively examined using data on 461 incident cases of colon cancer and 283 incident cases of rectal cancer that developed during 10.6 years (median) of follow-up among 26 630 men and 29 189 women taking part in the Diet, Cancer and Health cohort. Incidence rate ratios (IRRs) of colon and rectal cancer related to total or individual WG product intake were calculated using Cox regression.

Results:

Higher WG product intake was associated with lower risk of colon cancer and rectal cancer in men. The adjusted IRR (95% CI) was 0.85 (0.77–0.94) for colon cancer and 0.90 (0.80–1.01) for rectal cancer per daily 50 g increment in intake. For colon cancer the association was confined to intake of WG bread in particular. No consistent associations between total or individual WG product consumption and colon or rectal cancer risk were observed in women.

Conclusion:

The findings suggest that higher total WG product intake is associated with a lower risk of colon and perhaps rectal cancer in men, but not in women.