Lasing from active optomechanical resonators

Planar microcavities with distributed Bragg reflectors (DBRs) host, besides confined optical modes, also mechanical resonances due to stop bands in the phonon dispersion relation of the DBRs. These resonances have frequencies in the 10- to 100-GHz range, depending on the resonator's optical wavelength, with quality factors exceeding 1,000. The interaction of photons and phonons in such optomechanical systems can be drastically enhanced, opening a new route towards the manipulation of light. Here we implemented active semiconducting layers into the microcavity to obtain a vertical-cavity surface-emitting laser (VCSEL). Thereby, three resonant excitations--photons, phonons and electrons--can interact strongly with each other providing modulation of the VCSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein. As a result, modulation of the lasing intensity at frequencies up to 40 GHz is observed. From these findings, prospective applications of active optomechanical resonators integrated into nanophotonic circuits may emerge.

Incidence rates and trends of hip/femur fractures in five European countries: comparison using e-healthcare records databases

Hip fractures represent a major public health challenge worldwide. Multinational studies using a common methodology are scarce. We aimed to estimate the incidence rates (IRs) and trends of hip/femur fractures over the period 2003-2009 in five European countries. The study was performed using seven electronic health-care records databases (DBs) from Denmark, The Netherlands, Germany, Spain, and the United Kingdom, based on the same protocol. Yearly IRs of hip/femur fractures were calculated for the general population and for those aged ≥50 years. Trends over time were evaluated using linear regression analysis for both crude and standardized IRs. Sex- and age-standardized IRs for the UK, Netherlands, and Spanish DBs varied from 9 to 11 per 10,000 person-years for the general population and from 22 to 26 for those ≥50 years old; the German DB showed slightly higher IRs (about 13 and 30, respectively), whereas the Danish DB yielded IRs twofold higher (19 and 52, respectively). IRs increased exponentially with age in both sexes. The ratio of females to males was ≥2 for patients aged ≥70-79 years in most DBs. Statistically significant trends over time were only shown for the UK DB (CPRD) (+0.7% per year, P < 0.01) and the Danish DB (-1.4% per year, P < 0.01). IRs of hip/femur fractures varied greatly across European countries. With the exception of Denmark, no decreasing trend was observed over the study period.

Anomalies of a nonequilibrium spinor polariton condensate in a magnetic field

We observe a strong variation of the Zeeman splitting of exciton polaritons in microcavities when switching between the linear regime, the polariton lasing, and photon lasing regimes. In the polariton lasing regime the sign of Zeeman splitting changes compared to the linear regime, while in the photon lasing regime the splitting vanishes. We additionally observe an increase of the diamagnetic shift in the polariton lasing regime. These effects are explained in terms of the nonequilibrium "spin Meissner effect."

Brain control of volitional ankle tasks in people with chronic stroke and in healthy individuals

This study explored the relationships between motor cortical control of ankle dorsiflexors and clinical impairments of volitional ankle dorsiflexion in people with chronic stroke. Eighteen persons with stroke and 14 controls were evaluated. Clinical tools were used to assess ankle dorsiflexion amplitude and isometric strength. Transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) tested the functional integrity of cortical circuits controlling the tibialis anterior (TA). All clinical scores and most TMS outcomes were impaired in people with chronic stroke. The lower clinical scores were related to the reduction of the strength of corticospinal projections onto spinal motoneurons. Concurrent TMS and clinical testing in chronic stroke provided original data demonstrating relationships between the integrity of cortical and corticospinal components of TA motor control and volitional ankle tasks. Our study proposes that volitional ankle mobilization in chronic stroke may be explained by the residual abnormal M1 circuits which may be responsive for rehabilitation intervention. This should be confirmed in longitudinal studies with larger samples to determine whether TMS outcomes associated with lower limb muscles are predictive of clinical changes or vice versa.

Room temperature polariton light emitting diode with integrated tunnel junction

We present a diode incorporating a large number (12) of GaAs quantum wells that emits light from exciton-polariton states at room temperature. A reversely biased tunnel junction is placed in the cavity region to improve current injection into the device. Electroluminescence studies reveal two polariton branches which are spectrally separated by a Rabi splitting of 6.5 meV. We observe an anticrossing of the two branches when the temperature is lowered below room temperature as well as a Stark shift of both branches in a bias dependent photoluminescence measurement.

[Cutaneous mucormycosis caused by Rhizopus microsporus]

BACKGROUND

Mucormycosis are rare fungal infections occurring chiefly in the lung or the rhinocerebral compartment, particularly in patients with immunodeficiency or mellitus diabetes. We report the case of an elderly patient with cutaneous mucormycosis caused by Rhizopus microsporus.

PATIENTS AND METHODS

An 89-year-old man presented a skin lesion of the forearm rapidly becoming inflammatory and necrotic. The patient had been treated for 2months with oral corticosteroids for idiopathic thrombocytopenia. Histological and mycological examination of the skin biopsy revealed the presence of a filamentous fungus, R. microsporus. The outcome was unfavorable, despite prescription of high-dose liposomal amphotericin B.

DISCUSSION

Mucormycosis are infrequent opportunistic infections caused by angio-invasive fungi belonging to the Mucorales order. Cutaneous presentations are rare, and in rare cases the species R. microsporus is isolated in clinical samples. Diagnosis is based on histological examination highlighting the characteristic mycelium within infected tissue, together with ex vivo mycological identification using morphological and molecular methods. Treatment consists of liposomal amphotericin B combined with debridement surgery.

CONCLUSION

R. microsporus is a marginal fungal species rarely isolated in clinical practice, and even less in dermatology departments. This clinical case report highlights the severity of infection with this fungus, particularly in the absence of early surgery.

Systematic review of the efficacy and tolerability of clozapine in the treatment of youth with early onset schizophrenia

BACKGROUND

The use of clozapine (CLZ) for treatment-resistant schizophrenia is well established in adults. However, it is seldom used in youth with early onset schizophrenia (EOS) largely because of lack of clarity about its risk benefit ratio. This review synthesises and evaluates available evidence regarding the efficacy and tolerability of CLZ in EOS with the aim to assist clinical decision-making.

METHODS

We conducted a systematic review of the primary literature on the clinical efficacy and adverse drug reactions (ADRs) observed during CLZ treatment in EOS. We also identified relevant practice guidelines and summarised current guidance.

RESULTS

CLZ showed superior efficacy than other antipsychotics in treating refractory EOS patients; short-term clinical trials suggest an average improvement of 69% on the Brief Psychiatric Rating Scale that was sustained during long-term follow-up (up to 9 years). No fatalities linked to CLZ treatment were reported. Sedation and hypersalivation were the most common complaints, reported by over 90% of patients. Other common ADRs (reported in 10-60% of patients) were enuresis, constipation, weight gain, and non-specific EEG changes. Less common ADRs (reported in 10-30% of patients) were akathisia, tachycardia and changes in blood pressure. Neutropenia was reported in 6-15% of cases but was usually transient while agranulocytosis was rare (<0.1%). Seizures were also uncommon (<3%). Metabolic changes were relatively common (8-22%) but emergent diabetes was not frequently observed (<6%). Overall the rate of discontinuation was low (3-6%). Current guidelines recommend the use of CLZ in EOS patients who have failed to respond to two adequate trials with different antipsychotics and provide detailed schedules of assessments to evaluate and assess potential ADRs both prior to initiation and throughout CLZ treatment.

CONCLUSION

Available data although limited in terms of number of studies are consistent in demonstrating that CLZ is effective and generally safe in the treatment of refractory EOS provided patients are regularly monitored.

Spontaneous left atrial reentry tachycardias : radiofrequency ablation and outcome

AIMS

Spontaneous left atrial reentry tachycardias (LART) in patients without previous cardiac surgical or catheter ablation are rare. Several therapeutic concepts of catheter ablation have been suggested: linear lesions (LL), circumferential pulmonary vein isolation (PVI), and both (LL + PVI).

METHODS AND RESULTS

In all, 28 consecutive symptomatic patients with 51 LARTs presented to our institution for catheter ablation. Electroanatomical mapping was performed on 25 patients. Three patients were ablated conventionally during LART; 25 patients (89.3 %) had extensive low-voltage areas in the left atrium (atrial myopathy). One of the following ablation strategies was applied: first, LL (n = 8), second, PVI + LL (n = 11), and third PVI alone (n = 9). Fourteen patients (50 %) had a recurrent arrhythmia during a mean follow-up of 12.2 ± 11.1 months. Six patients presented with a recurrent LART (21.4 %), 4 with LART and atrial fibrillation (Afib) (14.3 %), and 4 with Afib (14.3 %). The recurrence rate of any arrhythmia (LART and Afib) was 37.5 % in the LL group, 44.4 % in the PVI group, and 63.6 % in the PVI + LL group (ns); the recurrence rate of LARTs was 12.5 % in the LL group, 22.2 % in the PVI group, and 63.6 % in the PVI + LL group (p < 0.05).

CONCLUSION

Atrial tachyarrhythmia recurrence after ablation of spontaneous LART in mid-term is considerable. Stable LARTs are effectively treated by LL. PVI alone may be an acceptable alternative, especially in patients with unstable LARTs and Afib. However, the risk of recurrent LARTs after a more extensive strategy with PVI and LL is considerable, probably due to proarrhythmic effects of long linear lesions.

Cardiac MRI: diagnostic gain of an additional axial SSFP chest sequence for the detection of potentially significant extracardiac findings in the cardiac MRI examination setting

PURPOSE

Cardiac MRI (CMRI) is an effective method for imaging of the heart. The aim of our study was to assess whether an axial chest sequence in addition to the standard CMR examination setting has advantages in the detection of potentially significant extracardiac findings (PSEF).

MATERIALS AND METHODS

400 consecutive patients were imaged at 1.5 T for clinical reasons. In addition to the standard long and short-axis views, an axial SSFP sequence was obtained covering the thorax from the lung apex to the diaphragm. All sequences were separately evaluated for PSEF.

RESULTS

A total of 25 PSEF were diagnosed in 400 patients, including 16 pleural effusions, a pulmonary fibrosis, a spondylodiscitis, ascites, lymphadenopathies, relapse of a mamma carcinoma, growth of adrenal glands metastases and diaphragmatic elevation. All 25 PSEF were detected by reading survey sequences. 24 of the 25 PSEF were detected by the additional SSFP chest sequence as well as the CINE sequences.

CONCLUSION

In our study the additional axial SSFP chest sequence didn't show a benefit in the detection of PSEF. With the survey sequences we were able to detect all PSEF. We conclude that survey images should be assessed for additional findings.

Homozygous and compound heterozygous MMP20 mutations in amelogenesis imperfecta

In this article, we focus on hypomaturation autosomal-recessive-type amelogenesis imperfecta (type IIA2) and describe 2 new causal Matrix metalloproteinase 20 (MMP20) mutations validated in two unrelated families: a missense mutation p.T130I at the expected homozygous state, and a compound heterozygous mutation having the same mutation combined with a nucleotide deletion, leading to a premature stop codon (p.N120fz*2). We characterized the enamel structure of the latter case using scanning electron microscopy analysis and microanalysis (Energy-dispersive X-ray Spectroscopy, EDX) and confirmed the hypomaturation-type amelogenesis imperfecta as identified in the clinical diagnosis. The mineralized content was slightly decreased, with magnesium substituting for calcium in the crystal structure. The anomalies affected enamel with minimal inter-rod enamel present and apatite crystals perpendicular to the enamel prisms, suggesting a possible new role for MMP20 in enamel formation.

Microcavity controlled coupling of excitonic qubits

Controlled non-local energy and coherence transfer enables light harvesting in photosynthesis and non-local logical operations in quantum computing. This process is intuitively pictured by a pair of mechanical oscillators, coupled by a spring, allowing for a reversible exchange of excitation. On a microscopic level, the most relevant mechanism of coherent coupling of distant quantum bits—like trapped ions, superconducting qubits or excitons confined in semiconductor quantum dots—is coupling via the electromagnetic field. Here we demonstrate the controlled coherent coupling of spatially separated quantum dots via the photon mode of a solid state microresonator using the strong exciton–photon coupling regime. This is enabled by two-dimensional spectroscopy of the sample’s coherent response, a sensitive probe of the coherent coupling. The results are quantitatively understood in a rigorous description of the cavity-mediated coupling of the quantum dot excitons. This mechanism can be used, for instance in photonic crystal cavity networks, to enable a long-range, non-local coherent coupling.

Controlling coupling between distant quantum objects is important for implementation of quantum technologies. Providing an important step towards using semiconductor structures for hosting optically controlled qubits, this work shows coherent coupling between three quantum dot excitons via a cavity.

Coherence expansion and polariton condensate formation in a semiconductor microcavity

The dynamics of the expansion of the first order spatial coherence g(1) for a polariton system in a high-Q GaAs microcavity was investigated on the basis of Young's double slit experiment under 3 ps pulse excitation at the conditions of polariton Bose-Einstein condensation. It was found that in the process of condensate formation the coherence expands with a constant velocity of about 10(8)  cm/s. The measured coherence is smaller than that in a thermal equilibrium system during the growth of condensate density and well exceeds it at the end of condensate decay. The onset of spatial coherence is governed by polariton relaxation while condensate amplitude and phase fluctuations are not suppressed.

Small scale boiling experiments using two-dimensional imaging with high-speed camera and optical coherence tomography

To investigate boiling processes, a test facility has been constructed, which allows the use of optical techniques for the detection of individual vapor bubbles. Demineralized water was used as working fluid at ambient pressure whereat temperature, flow rate and heat flux density can be varied. The growth of individual vapor bubbles was recorded by high-speed camera and analyzed by digital image processing (DIP). Optical coherence tomography (OCT) enabled the visualization of steam bubbles in cross-sections perpendicular to the heated surface.

[Injuries in male and female adolescent soccer players]

This study addresses the epidemiology of injuries in adolescent male and female soccer players in Germany. Therefore, the purpose of the study was to analyse the injuries in male and female youth soccer players in Germany. This study was designed as a cross-sectional web-based survey. From March until December 2011 we investigated 1110 soccer players (male n = 841; female n = 269) aged 12 - 19 years (15.0 ± 2.0 years) from 60 clubs in Southern Germany. A total of 664 (79 %) of the 841 boys and 67 (25 %) of the 269 girls reported being injured due to soccer. The total number of injuries was 2373. Respectively the frequency of injury was 2.85 in boys and 7.10 in girls. The lower extremities were affected in 70 % of all reported cases. Strains were the most common injuries in the lower and upper extremities (35 %). The boys reported in 51.5 % of all injuries that the injury was non-contact in nature. In contrast, 52.1 % of the injuries in girls were reported as contact injuries. Similar amounts of injuries were observed in training versus games for both genders. Prevention procedures, such as a thorough warm-up, should be implemented before every game and training to reduce the risk of injury.

[The prevalence of Parkinson's disease, associated dementia, and depression in Dresden]

BACKGROUND

Parkinson's disease (PD) is frequently compounded by dementia and depression. Yet local total estimates on the prevalence of PD with dementia/depression are still lacking. These are socioeconomically important, especially for the eastern federal states in Germany due to the demographic structures.

METHODS

We conducted a two-staged total estimation in the area of Dresden. First, all local office-based neurologists, hospitals and retirement homes were asked to list their patients/residents with PD on a single study day. Then a random sample of patients/home residents was neuropsycholoigcally examined, including the Mini-mental-state exam and the Montgomery-Asberg Depression rating scale. Dementia was diagnosed according to DSM-IV criteria.

RESULTS

Overall, 886 PD cases (95 % CI: 809 - 926) were estimated, of which 252 (95 % CI: 226 - 279) suffered from dementia and 216 (95 % CI: 191 - 242) from depression. Dementia rates increased by age with 13.8 % (≤ 65 years) to 40.2 % (≥ 76 years). Depression rates ranged from 23.3 % to 28.0 %. Overall, 20.6 % of all ambulatory treated PD patients and 85.7 % of all home residents with PD had dementia.

CONCLUSION

The prevalence of PD in Dresden dovetails with previous reported estimates. Dementia and depression are frequent complications in outpatients as well as home residents with PD.

On-chip quantum optics with quantum dot microcavities

A novel concept for on-chip quantum optics using an internal electrically pumped microlaser is presented. The microlaser resonantly excites a quantum dot microcavity system operating in the weak coupling regime of cavity quantum electrodynamics. This work presents the first on-chip application of quantum dot microlasers, and also opens up new avenues for the integration of individual microcavity structures into larger photonic networks.

Mobilization of PBSC for allogeneic transplantation by the use of the G-CSF biosimilar XM02 in healthy donors

The human recombinant G-CSF filgrastim has been widely used for the mobilization of CD34⁺ stem cells of healthy donors (HD). In 2008, the G-CSF biosimilar XM02 (Ratiograstim, Tevagrastim and Biograstim) was approved by the European Medicines Agency (EMA) for the mobilization of PBSC. However, there is limited experience in the application of biosimilar G-CSF for the mobilization of PBSC especially in HD. Therefore, we investigated in two cohorts (n=22), the efficacy and safety of PBSC mobilization by either biosimilar G-CSF or reference G-CSF. We observed a similar yield of CD34⁺ stem cells as well as CD3⁺ T-cells and nucleated cells in both groups and a safe engraftment in all patients with similar reconstitution of hematopoiesis in all hosts. In summary, we found a comparable efficacy and safety of biosimilar G-CSF when compared with reference G-CSF.

Morphological and molecular insights on Megalothorax: the largest Neelipleona genus revisited (Collembola)

The genus Megalothorax Willem, 1900 is redefined along with a redescription of the type species M. minimus Willem, 1900 and the description of five new species (M. granulosus, sp. nov., M. nigropunctatus, sp. nov., M. perspicillum, sp. nov., M. svalbardensis, sp. nov. and M. willemi, sp. nov.). We describe and comment on broad sets of discriminating characters for Megalothorax systematics. For the first time, trichobothria are recorded for Neelipleona, probably of generic importance. The described species are provided with DNA data (COI, 16S and 28S) and included in a molecular-based phylogenetic analysis. The traditional distinction between minimus-group and incertus-group is discussed in the light of DNA and morphology components. A key to the worldwide Megalothorax species is provided.

Site-controlled growth of InP/GaInP quantum dots on GaAs substrates

A technology platform for the epitaxial growth of site-controlled InP quantum dots (QDs) on GaAs substrates is presented. Nanoholes are patterned in a GaInP layer on a GaAs substrate by electron beam lithography and dry chemical etching, serving as QD nucleation centers. The effects of a thermal treatment on the structured surfaces for deoxidation are investigated in detail. By regrowth on these surfaces, accurate QD positioning is obtained for square array arrangements with lattice periods of 1.25 μm along with a high suppression of interstitial island formation. The optical properties of these red-emitting QDs (λ ~ 670 nm) are investigated by means of ensemble- and micro-photoluminescence spectroscopy at cryogenic temperatures.

Calcitonin screening in patients with thyroid nodules. Diagnostic value

AIM

The positive predictive value (PPV) of a slightly elevated basal calcitonin (CT) for the diagnosis of medullary thyroid cancer (MTC) is still under debate.

PATIENTS, METHODS

A total of 11270 patients with thyroid nodules underwent calcitonin screening. Patients with known elevation of CT, renal insufficiency, bacterial infection, alcohol abuse, proton-pump inhibitor therapy or autoimmune thyroid disease were excluded from further analysis. Serum CT was determined by the solid-phase, enzyme-labeled, two-site chemiluminescent immunoassay Immulite 2000. If possible, a pentagastrin test was done to differentiate cases of hypercalcitoninaemia.

RESULTS

Hypercalcitoninsemia was found in 32 patients. 20 patients underwent surgery. In 10 patients a MTC was found. The PPV of hypercalcitoninaemia for MTC was 31%. The PPV increased to 50% for those patients who underwent surgery (10/20). A subgroup of 26 patients presented with basal CT between 13 and 50 pg/ml, 14 of them underwent surgery, in 4 cases evidence of MTC was revealed. This resulted in a PPV of 15% (4/26), although the value increased to 28% when only surgically treated patients were considered (4/14).

CONCLUSION

Taking all clinical data into account, calcitonin screening has an acceptable PPV for medullary thyroid cancer in patients with thyroid nodules. Therefore, we recommend calcitonin screening in centers for thyroid disorders.

Recombinant Human TSH Increases Uptake and Effective Half-life of Radioiodine in Thyroid Hormone Secreting Metastases of Follicular Thyroid Cancer

Follicular thyroid cancer with thyroid hormone secreting metastases is an extremely rare condition, with only a few cases reported world-wide.

We here present the case of a 64-year-old female patient affected by follicular thyroid cancer with extensive thyroid hormone secreting metastases leading to TSH-suppression.

We have also summarized the relevant diagnostic and therapeutic approaches and describe, for the first time, the effects of rhTSH-application in this rare tumor entity.

In this patient, we found that rhTSH increased 131I-uptake into the thyroid hormone secreting metastases and prolonged the effective half-life of 131I. These effects of rhTSH should be considered when fixed activities of 131I are prescribed.

Factors Associated with the Duration of Breastfeeding in the Freiburg Birth Collective, Germany (FreiStill)

Purpose: The health benefits of breastfeeding for both infants and mothers are well-documented. The aim of this study was to clarify factors associated with successful breastfeeding. Methods: We performed a prospective, multi-centre cohort study of 443 mothers in person using a standardised questionnaire on postpartum day 1. Women who had started to breast-feed were interviewed by telephone after 3, 6 and 12 months. A statistical analysis was performed using the SAS system. Results: 92 % of women (409/443) were initially breastfeeding. After three months the rate decreased to 74 %, after six months to 61 % and after 12 months to 28 %, respectively. Bivariate analysis revealed a significant positive association with the following factors: maternal age > 35 years, higher educational level, intention to breastfeed on postpartum day one, high motivation after three months, partner's support of the decision to breastfeed, satisfaction with the care provided in the maternity clinic, a positive breastfeeding experience and follow-up care by a midwife. Elective caesarean delivery, the use of breastfeeding aids, formula supplementation early on and the mother's concern about the amount of milk correlated negatively. Following a multivariate logistic regression analysis, four factors were correlated with having a positive influence on duration of breastfeeding: higher educational level, satisfaction with the care provided within the maternity clinic, follow-up care by a midwife, and a positive current experience of breastfeeding. Conclusion: Our data demonstrate certain factors successfully influence breastfeeding. Competent care in the maternity clinic, postpartum care by a midwife and a positive experience with breastfeeding increase the rate of breastfeeding and thus have a positive impact on the health of mother and newborn.

[NT-proBNP as a diagnostic marker in dogs with dyspnea and in asymptomatic dogs with heart murmur]

OBJECTIVE

The cardiac biomarker NT-proBNP indicates cardiac load in terms of myocardial wall stress. The objective of the study was to compare the results of NT-proBNP measurements in healthy dogs and dogs with dyspnea as well as asymptomatic dogs with heart murmur with the literature.

MATERIAL AND METHODS

Between April 2007 and December 2007 dogs with dyspnea of non-cardiac origin (n=11), dogs with dyspnea of cardiac origin (n=18) and asymptomatic dogs with heart murmur (n=22) were included. Twelve clinically healthy dogs served as a control group. All animals underwent cardiologic examination including echocardiography and measurement of serum NT-proBNP concentration. Serum was centrifuged and frozen within 30 minutes and was stored frozen until analysis was performed.

RESULTS

Median NT-proBNP concentration in healthy dogs was 240 pmol/l (range 131-546 pmol/l). Dogs with dyspnea and primary respiratory disease displayed a median NT-proBNP concentration of 876 pmol/l (range 97-2614 pmol/l). In patients with dyspnea of non-cardiac origin, there was a difference in the values of NT-proBNP of dogs with and without pulmonary hypertension diagnosed by echocardiography. Dogs with dyspnea of cardiac origin displayed a median NT-proBNP concentration of 2000 pmol/l (range 137-2614 pmol/l). Low normal NT-proBNP values were only found in patients with pericardial effusion. Median NT-proBNP concentration in asymptomatic dogs with heart murmur was 698.5 pmol/l (range 121-2614 pmol/l). Considerably increased values were particularly measured in asymptomatic patients with severe congenital heart disease.

CONCLUSION AND CLINICAL RELEVANCE

NT-proBNP represents a useful additional diagnostic parameter in veterinary clinical cardiology to assess the severity of cardiac disease. Interpretation must take into consideration the clinical picture of the patient, as dogs with severe arrhythmias, sepsis and pulmonary thromboembolism may display high NT-proBNP levels without congestive heart failure. Our results indicate the following cut-off values: <500 pmol/l: no relevant cardiac load; 500-900 pmol/l: moderate cardiac load; >900 pmol/l: severe cardiac load.

P3-18-04: Pathway Guided Selection of Targeted Inhibitors for Breast Cancer Treatment

Background: The ability to functionally profile a whole spectrum of pathway proteins in tumor may provide valuable information about the likelihood of drug response and potential mechanisms for drug resistance in breast cancer (BCA) patients. Here we report a comprehensive pathway analysis of membrane associated kinases such as HER1, HER2, HER3, cMET, IGF1R, PI3K and downstream signal transduction proteins including Shc, AKT, ERK, MEK, PDK1, PRAS40, p70S6K and eIF4e in breast cancer cell lines and xenografts as in response to inhibitors targeting the Her1/Her2 and PI3K/AKT and MAPK pathways. For comparison we also analyzed NSCLC lines driven by other receptor tyrosine kinases like EGFR and MET. Methods: Lysates prepared from KPL4 cells and MCF7 cells both harboring PIK3CA mutations (with HER2−amplification and low level HER2 expression, respectively) treated with 6 inhibitors (an allosteric AKT inhibitor, Lapatinib, Regorafenib, MET inhibitor, an allosteric MEK inhibitor or PI3K inhibitor) targeting PI3K/AKT and MAPK pathways were analyzed for modulations of pathway protein phosphorylation using a multiplexed immuno-micorarray.

Tissue lysates prepared from KPL4 xenografts treated with AKT inhibitor were analyzed for pathway modulation in response to the drug treatment. The pathway activation profile shift in response to drug treatments in BCA models are compared to other tumor type models with diverse oncogenic backgrounds.

Results: The level of phosphorylated AKT (pAKT) was reduced when MCF7 cells were treated with AKT inhibitor as well as PI3K inhibitor. However, compensatory AKT activation was observed when these cells were treated with BRAF or MEK inhibitor. KPL4 cells also showed reduction of pAKT when treated with Lapatinib, AKT inhibitor or PI3K inhibitor. Compensatory hyper-phosphorylation of ERK (pERK) was observed in both cell lines and KPL4 xenografts with AKT inhibitor treatment while PI3K inhibition did not induce hyper-ERK phosphorylation. Reduction of pERK level was observed when both cell lines were treated with MEK inhibitor. Downstream analytes like PRAS40 and RPS6 summarize PI3K/AKT pathway activity and correlate well with response to treatment whereas eIF4e is a good final readout for activity in the RAS/RAF/MEK/ERK pathway. Treatment with single agents often even shows adverse profile shift through feedback or pathway cross-talk. The comparative analysis of pathway modulation in BCA models to other tumor types in response to drug treatments revealed several adaptive drug resistance mechanism with different oncogenic backgrounds.

Discussion: Evaluation of drug specific pathway modulations in cancer cells provided comprehensive information on efficacy of specific agents on target protein and pathway inhibition. Multiplexed pathway analysis provides valuable information for drug resistance mechanisms due to either redundant pathway activation, cross-talk or through feedback mechanism and may guide appropriate selection of targeted drug-combinations or drug-sequencing in clinical setting. For example, the observed increase in ERK phosphorylation due to AKT inhibition could be blocked by combination therapy with a MEK inhibitor.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-18-04.

Low copy number DNA profiling from isolated sperm using the aureka®-micromanipulation system

A new cell isolation technique linked to the aureka® micromanipulation system (aureka®) was used to pick sperm from mixed samples containing sperm and epithelial cells. Both cell types were stained using the HY-LITER™ high-resolution, fluorescent staining kit. To isolate a single sperm of interest under a fluorescent microscope, a specific microsphere picking technique was used. This sensitive and reliable cell identification and isolation technique enables low-copy-number (LCN) DNA profiling, as few as 20 sperm are sufficient for obtaining a full short tandem repeat (STR) profile without any allelic drop out. The presented protocol covers the whole workflow, from sample staining and cell pick up to STR analysis.