Memory technology-a primer for material scientists.

From our own experience, we know that there is a gap to bridge between the scientists focused on basic material research and their counterparts in a close-to-application community focused on identifying and solving final technological and engineering challenges. In this review, we try to provide an easy-to-grasp introduction to the field of memory technology for materials scientists. An understanding of the big picture is vital, so we first provide an overview of the development and architecture of memories as part of a computer and call attention to some basic limitations that all memories are subject to. As any new technology has to compete with mature existing solutions on the market, today's mainstream memories are explained, and the need for future solutions is highlighted. The most prominent contenders in the field of emerging memories are introduced and major challenges on their way to commercialization are elucidated. Based on these discussions, we derive some predictions for the memory market to conclude the paper.

Induction chemotherapy (IC) followed by radiotherapy (RT) versus cetuximab plus IC and RT in advanced laryngeal/hypopharyngeal cancer resectable only by total laryngectomy-final results of the larynx organ preservation trial DeLOS-II.

Background: The German multicenter randomized phase II larynx organ preservation (LOP) trial DeLOS-II was carried out to prove the hypothesis that cetuximab (E) added to induction chemotherapy (IC) and radiotherapy improves laryngectomy-free survival (LFS; survival with preserved larynx) in locally advanced laryngeal/hypopharyngeal cancer (LHSCC). Patients and methods: Treatment-naïve patients with stage III/IV LHSCC amenable to total laryngectomy (TL) were randomized to three cycles IC with TPF [docetaxel (T) and cisplatin (P) 75 mg/m2/day 1, 5-FU (F) 750 mg/m2/day days 1-5] followed by radiotherapy (69.6 Gy) without (A) or with (B) standard dose cetuximab for 16 weeks throughout IC and radiotherapy (TPFE). Response to first IC-cycle (IC-1) with ≥30% endoscopically estimated tumor surface shrinkage (ETSS) was used to define early responders; early salvage TL was recommended to non-responders. The primary objective was 24 months LFS above 35% in arm B. Results: Of 180 patients randomized (July 2007 to September 2012), 173 fulfilled eligibility criteria (A/B: larynx 44/42, hypopharynx 41/46). Because of 4 therapy-related deaths among the first 64 randomized patients, 5-FU was omitted from IC in the subsequent 112 patients reducing further fatal toxicities. Thus, IC was TPF in 61 patients and TP in 112 patients, respectively. The primary objective (24 months LFS above 35%) was equally met by arms A (40/85, 47.1%) as well as B (41/88, 46.6%). One hundred and twenty-three early responders completed IC+RT; their overall response rates (TPF/TP) were 94.7%/87.2% in A versus 80%/86.0% in B. The 24 months overall survival (OS) rates were 68.2% and 69.3%. Conclusions: Despite being accompanied by an elevated frequency in adverse events, the IC with TPF/TP plus cetuximab was feasible but showed no superiority to IC with TPF/TP regarding LFS and OS at 24 months. Both early response and 24 months LFS compare very well to previous LOP trials and recommend effective treatment selection and stratification by ETSS. Clinical trial information: NCT00508664.

[The value of supracricoid partial laryngectomy in moderately advanced laryngeal cancer (T3-T4a)]. / Stellenwert der suprakrikoidalen Teilresektion beim moderat fortgeschrittenen Glottiskarzinom (T3-T4a).

BACKGROUND: Transoral laser microsurgery (TLM) is the method of choice for partial laryngectomy in Germany. In advanced stages, chemoradiotherapy is increasingly indicated for organ preservation. OBJECTIVE: This report considers the indications for and outcomes of supracricoid partial laryngectomy (SPL), also known as crico-hyoido-(epiglotto)-pexy, as an option for surgical organ preservation in moderately advanced laryngeal cancer (T3-T4a), in the well-defined gap between TLM and chemoradiotherapy protocols in Germany. METHODS: Retrospective evaluation of functional and oncological outcomes of all SPLs conducted between 2008 and 2014. During this period, 17 SPLs with resection of rpT2 (n = 2), (r)pT3 (n = 11), and (r)pT4a (n = 4) were performed with resection of one arytenoid. Mean age was 58 years (range 47-75 years). In 5 patients, SPL was for a first or second local recurrence after TLM or open partial laryngectomy. Adjuvant radiotherapy was received by 7 patients staged pT4a or pN+. RESULTS: Salvage laryngectomy with adjuvant radiotherapy was required by 2 patients. The remaining patients (n = 15) had a mean tumor-free follow-up of 4 years with a functional intact larynx: these patients can eat and drink, have a closed tracheotomy, and a good voice. After 3 years tumor-free follow-up with a functional intact larynx, 2 patients died due to cardiac comorbidity at the age of 76 years. DISCUSSION: SPL is a rare but valuable option for surgical larynx preservation in stage pT3-4a laryngeal cancer.

Laryngomalacia and complicated, life-threatening mTOR-positive Kaposiform hemangioendothelioma cured by Supraglottoplasty and sirolimus.

The therapy of complicated Kaposiform hemangioendothelioma (KHE) is still difficult. We present the first case of laryngomalacia with simultaneous mammalian target of Rapamycin (mTOR)-positive KHE of the neck and thoracic inlet and concurrent Kasabach-Meritt Phenomenon (KMP) in an 11-month-old boy suffering life-threatening progress despite intravenous vincristine, corticosteroids, propranolol and local interstitial laser-application. The laryngomalacia restored after laser-supraglottoplasty. Successfully treatment of the prior fatal course of the KHE with KMP was initiated not till adding the mTOR inhibitor sirolimus to therapy. After 16 months single therapy of KHE with oral sirolimus the boy presented free of symptoms with minimal residual disease and excellent functional long-term results. Thus we stopped sirolimus therapy. The results are stable for 9 months without therapy. The special features including full report of histopathologic findings of this utmost complicated case are demonstrated in detail underlining the effectiveness of sirolimus for KHE.

Decline of lactate in tumor tissue after ketogenic diet: in vivo microdialysis study in patients with head and neck cancer.

In head and neck squamous cell carcinoma (HNSCC) aerobic glycolysis is the key feature for energy supply of the tumor. Quantitative microdialysis (µD) offers an online method to measure parameters of the carbohydrate metabolism in vivo. The aim was to standardize a quantitative µD-study in patients with HNSCC and to prove if a ketogenic diet would differently influence the carbohydrate metabolism of the tumor tissue. Commercially available 100 kDa-CMA71-µD- catheters were implanted in tumor-free and in tumor tissue in patients with HNSCC for simultaneous measurements up to 5 days. The metabolic pattern and circadian rhythm of urea, glucose, lactate, and pyruvate was monitored during 24 h of western diet and subsequent up to 4 days of ketogenic diet. After 3 days of ketogenic diet the mean lactate concentration declines to a greater extent in the tumor tissue than in the tumor-free mucosa, whereas the mean glucose and pyruvate concentrations rise. The in vivo glucose metabolism of the tumor tissue is clearly influenced by nutrition. The decline of mean lactate concentration in the tumor tissue after ketogenic diet supports the hypothesis that HNSCC tumor cells might use lactate as fuel for oxidative glucose metabolism.

[Dysplasia and laryngeal carcinoma in situ]. / Dysplasien und Carcinomata in situ des Larynx.

Although the glottis is amenable to chemotherapy, currently most lesions from stage I laryngeal dysplasia up to carcinoma in situ are excised. This literature review presents selected molecular biological aspects especially in relation to dysplasia of the larynx and its therapy, as well as currently preferred biomarkers for chemotherapeutic prevention of laryngeal dysplasia.

Hyperechogenicity of the substantia nigra in healthy controls is related to MRI changes and to neuronal loss as determined by F-Dopa PET.

Transcranial ultrasound (TCS) has been shown to reveal hyperechogenicity of the substantia nigra (SN) in Parkinsonian patients and in about 10% of healthy controls. It is hypothesized that SN hyperechogenicity in healthy subjects is a vulnerability marker for idiopathic Parkinson's disease (IPD). Although there is strong evidence that the echomarker results from increased local iron content, the exact pathophysiological mechanisms remain incompletely understood. Thus, prognostic impact can only be estimated. We examined 14 subjects with SN hyperechogenicity (SN+) (7 IPD patients and 7 controls) and 7 healthy controls without the echomarker (SN-) by a magnetic resonance imaging method (MRI; T2 relaxation times) known to reveal tissue inhomogeneity following abnormal iron content and by F-Dopa PET to assess nigrostriatal function.

Disgust in pre-clinical Huntington's disease: a longitudinal study.

Emotion recognition from both face and voice and experience of emotions were investigated in a group of non-symptomatic people at risk of carrying the Huntington's disease gene who presented for genetic testing. Based on the results of the DNA test, a group of people carrying the Huntington's disease gene (HD+), and a group of non-carriers (HD-) were formed. Since we were especially interested in the time course of possible deficits in emotion recognition, all people at risk were reassessed 6 and 12 months after the initial assessment. Recognising facial expressions of disgust was significantly impaired on all three assessments in the HD+ group, while recognition of vocal emotions and the experience of emotions were largely unaffected, confirming that deficits in recognition of facial expressions of disgust are an early correlate of carrying the gene for Huntington's disease. The inclusion of a healthy control group (n = 37) further allowed an estimate of the genetic and environmental contribution to deficits in facial emotion recognition.

Facial expression recognition in people with medicated and unmedicated Parkinson's disease.

Recognition of facial expressions of emotion was investigated in people with medicated and unmedicated Parkinson's disease (PD) and matched controls (unmedicated PD, n=16; medicated PD, n=20; controls, n=40). Participants in the medicated group showed some visual impairment (impaired contrast sensitivity) and performed less well on perception of unfamiliar face identity, but did not show significant deficits in the perception of sex, gaze direction, or familiar identity from the face. For both Parkinson's disease groups, there was evidence of impaired recognition of facial expressions in comparison to controls. These deficits were more consistently noted in the unmedicated group, who were also found to perform worse than the medicated group at recognising disgust from prototypical facial expressions, and at recognising anger and disgust in computer-manipulated images. Although both Parkinson's disease groups showed impairments of facial expression recognition, the consistently worse recognition of disgust in the unmedicated group is consistent with the hypothesis from previous studies that brain regions modulated by dopaminergic neurons are involved in the recognition of disgust.

Knowing no fear.

People with brain injuries involving the amygdala are often poor at recognizing facial expressions of fear, but the extent to which this impairment compromises other signals of the emotion of fear has not been clearly established. We investigated N.M., a person with bilateral amygdala damage and a left thalamic lesion, who was impaired at recognizing fear from facial expressions. N.M. showed an equivalent deficit affecting fear recognition from body postures and emotional sounds. His deficit of fear recognition was not linked to evidence of any problem in recognizing anger (a common feature in other reports), but for his everyday experience of emotion N.M. reported reduced anger and fear compared with neurologically normal controls. These findings show a specific deficit compromising the recognition of the emotion of fear from a wide range of social signals, and suggest a possible relationship of this type of impairment with alterations of emotional experience.

Neuroleptics ameliorate phencyclidine-induced impairments of short-term memory.

1. Phencyclidine (PCP), a non-competitive NMDA-receptor antagonist, is able to induce schizophrenia-like symptoms in animals and in humans. It is known that schizophrenic patients have deficits in memory processes. 2. Therefore, it was investigated whether subchronic pulsatile or continuous application of 5.0 mg kg(-1) PCP over 5 days induce short-term memory deficits in holeboard learning and the action of two different neuroleptics on this behavioural test. 3. First, an impairment in the holeboard task was described when the animals were tested 24 h after the last application but not after 15 min or 1 h after the last injection. Secondly, the influence of haloperidol and risperidone on the PCP-induced short-term memory changes was tested. 4. The combined application of PCP and risperidone led to a complete antagonism of the short-term deficits, but the combined treatment with haloperidol was accompanied by a partial abolishment of the PCP-induced deficits. 5. PCP led to an upregulation of the glutamate binding sites in striatum and nucleus accumbens whereas the D(2) binding sites were reduced in striatum. The D(1) binding sites seem to be unchanged. The receptor protein expression of glutamate receptors mGluR1, GluR2, GluR5/7 and NMDAR1 were not modified in response to PCP treatment. 6. The determination of a subpopulation of GABAergic interneurons shows a decrease of the cells within the CA3 of the hippocampal formation. 7. These findings indicate that PCP induced impairments in short term memory can be detected by holeboard learning and may provide an interesting tool for the search of new neuroleptics.

Neuroblastoma directed therapy by a rational prodrug design of etoposide as a substrate for tyrosine hydroxylase.

Tumor directed cytotoxic therapy is one of the major challenges for the success of chemotherapy. In order to accomplish this goal in neuroblastoma, we rationally designed a prodrug of etoposide as substrate for tyrosine hydroxylase, a well established neuroblastoma associated enzyme. Here, we report synthesis and characterization of a 3,4 dihydroxy-phenyl carbamate derivative of etoposide. In order to demonstrate activation by tyrosine hydroxylase, the coding sequence of murine tyrosine hydroxylase was generated by reverse transcriptase-polymerase chain reaction from NXS2 neuroblastoma cells and cloned into the pRSET-A bacterial expression vector. The enzyme was expressed in Escherichia coli, characterized by Western blot and enzymatic activity was demonstrated by conversion of tyrosine into DOPA in the presence of cofactors using reversed phase high-performance liquid chromatography. Under these enzymatic conditions, we demonstrate conversion of 3,4 dihydroxy-phenyl carbamate prodrug into free etoposide. This effect was clearly mediated by the enzyme since bacteria transformed with the empty vector were ineffective of prodrug activation. Furthermore, tyrosine hydroxylase positive cells exposed to the etoposide prodrug were effectively killed in contrast to tyrosine hydroxylase negative controls. These findings demonstrate that etoposide can be designed as a prodrug substrate for tyrosine hydroxylase and thereby establish proof of concept for neuroblastoma directed enzyme prodrug therapy.

Rationally designed hydrolytically activated etoposide prodrugs, a novel strategy for the treatment of neuroblastoma.

Effective chemotherapy in neuroblastoma is limited by poor anti-tumor efficacy, systemic toxicity and the induction of drug resistance. Here, we provide further evidence that a hydrolytic activated prodrug design may overcome these problems. For this purpose, VP-16 was functionally blocked by a carbonate linker to generate two novel chemically stable prodrugs of VP-16, ProVP-16 I and II. We demonstrate profoundly different biological effects in vitro and in vivo of the prodrugs compared to parental VP-16. First, we established an up to >2 log higher in vitro toxicity of the two prodrugs compared to VP-16 on a panel of neuroblastoma cell lines. The highest increase of prodrug mediated cytotoxicity was observed in multi drug resistant cell lines. Second, in vivo studies showed a maximum tolerated dose (MTD) of ProVP-16 II (60 mg/kg), which was at least threefold higher than that of VP-16 (20 mg/kg). Tests of ProVP-16 II in a syngeneic NXS2 neuroblastoma model indicated that mice treated with this prodrug at 1/3 of the MTD was as effective as VP-16 parental compound used at the MTD in suppression of tumor growth. In summary, the etoposide prodrugs proved effective and less toxic and are therefore highly promising new anti-neuroblastoma compounds.

Efficacy of oral dalargin-loaded nanoparticle delivery across the blood-brain barrier.

The Leu-enkephalin dalargin normally does not penetrate the blood-brain barrier (BBB) when given intravenously. To transport dalargin across the blood-brain barrier, the peptide was adsorbed onto the surface of poly(butyl)cyanoacrylate nanoparticles and coated with polysorbate 80. After systemic administration the central analgesia was measured by hot plate test. Furthermore, nanoparticles were fabricated with different stabilizers. After the adsorption of the peptide on polysorbate 85 stabilized nanoparticles analgesia was observable after intravenously and oral application even when nanoparticles were not coated. Thus, our data support the usefulness of nanoparticles as a method to deliver drugs to the brain.

Peptidase D of Escherichia coli K-12, a metallopeptidase of low substrate specificity.

Peptidase D of Escherichia coli was overproduced from a multicopy plasmid and purified to electrophoretic homogeneity. The pure enzyme was stable at 4 degrees C or -20 degrees C and had a pH optimum at pH 9, and a pI of 4.7; the temperature optimum was at 37 degrees C. As the enzyme was activated by Co2+ and Zn2+, and deactivated by metal chelators, it appears to be a metallopeptidase. By activity staining of native gels, 11 dipeptides which are preferentially cleaved by peptidase D were identified. Peptidase D activity required dipeptide substrates with an unblocked amino terminus and the amino group in the alpha or beta position. Non-protein amino acids and proline were not accepted in the C-terminal position, whereas some dipeptide amides and formyl amino acids were hydrolyzed. Km values of 2 to 5 mM indicate a relatively poor interaction of the enzyme with its substrates.

Small drug sample fabrication of controlled release polymers using the microextrusion method.

Ethylene vinylacetate polymer (EVA) has been used for many years to fabricate controlled-release polymeric implant devices with which drugs of high or low molecular weight compounds could be delivered with zero-order kinetics. However, because the known fabrication methods such as solvent evaporation, casting and possible shrinkage are not sufficiently controllable we have now developed the microextrusion method with which even small amount of clinically important and expensive drugs can be incorporated into EVA with high reproducibility. We show here that devices produced by the microextrusion method allows for a controlled delivery of several neurotoxic and neurotherapeutic compounds such as alpha-methyl-p-tyrosine, diazepam, quinolinic acid, and phencyclidine. Each substance is slowly released from the polymer, as evidenced by spectrophotometric data, for up to 120 days at daily rates varying from 18.4 microg of phencyclidine to 97.6 microg/day of diazepam. Thus, microextrusion is a valuable method for fabricating controlled-release polymers in which small amounts of scarce drugs can be incorporated. Another advantage of the current procedure is that polymers can be fabricated with very little amount of solvent.

Simulation of psychosis by continuous delivery of phencyclidine from controlled-release polymer implants.

To simulate psychosis in rats we have developed a method for the continuous delivery of phencyclidine (PCP) using implantable controlled-release polymers. PCP polymer implants produced deficits in latent inhibition which do not occur after repeated bolus injections. PCP implanted rats were also devoid of any anxiogenic signs, motoric hyperactivity and learning acquisition which can be seen in rats receiving daily bolus injections of a comparable PCP dose. This behavioral double-dissociation of the two modes of PCP application was accompanied by respective neurochemical changes. PCP binding sites were reduced in both striatum and hippocampus, but in the hippocampus, loss of PCP binding sites was more severe following pulsatile PCP administration. Morphological assessment revealed a significant shrinkage of the CA3 region in hippocampus in both groups. Pharmacokinetic analysis showed that the maximum PCP concentration in the brain after bolus injections was 10-fold above the PCP implants.

Efficacy and benefit of mediastinal computed tomography as a selection method for mediastinoscopy.

In 95 consecutive patients with proven or suspected bronchial carcinoma, computed tomographic evaluation of the upper mediastinum for N2 disease was performed prospectively. Patients with positive results underwent mediastinoscopy. Patients with perinodal N2 or N3 disease at mediastinoscopy were not considered candidates for operation. The mediastinum was declared negative only when intraoperative mediastinal lymph node dissection showed tumor-free nodes. Of the 95 patients, 12 had benign lesions, 14 were excluded from further evaluation because the lymph node status of the mediastinum was not proven intraoperatively, and 6 others were excluded from the final evaluation because of violation of the protocol. Twenty-two of the 75 remaining patients had a positive computed tomographic scan and underwent mediastinoscopy. Fourteen patients with positive results were considered to have inoperable disease. Fifty-three patients (70.7%) did not undergo mediastinoscopy. We performed seven probably incomplete resections, two for palliative reasons, and two thoracotomies without resection in patients with N2 disease. A policy of routine mediastinoscopy would have prevented only 5% of the thoracotomies performed in patients with lung cancer.

The effect of pentylenetetrazol kindling on synaptic mechanisms of interacting glutamatergic and opioid system in the hippocampus of rats.

Endogenous opioids modulate processes of central excitability such as long-term potentiation and electrical kindling. Little is known about the neurochemical alterations in the interaction of the glutamatergic and opioid system in the development of pentylenetetrazol (PTZ) kindling in rats. Therefore, in the present study we investigated glutamate, DAMGO and naltrindole receptor binding, receptor protein expression by Western blot and ex vivo glutamate transmitter release in PTZ kindled rats. The specific 3H-DAMGO and -naltrindole binding to hippocampal membranes displayed no significant changes in kindled rats compared to controls. In contrast, the 3H-l-glutamate binding was significantly enhanced after completion of PTZ kindling. The expression of receptor protein for glutamate as well as the naloxone- and naltrindole-induced 3H-d-aspartate release from hippocampal slices did not alter in any case as a consequence of PTZ kindling. The PTZ induced enhancement of the glutamate binding sites in the hippocampus was downregulated to control level by natrindole treatment of rats prior to each PTZ application. Furthermore, naltrindole pretreatment of rats significantly inhibited the development of seizure susceptibility. In contrast, naloxone was not able to alter the seizure activity induced by PTZ as well as the transmitter receptor binding. The results are discussed in the light of a modulating role of delta-opioid receptors in PTZ kindling.

Diffusion enhancement of drugs by loaded nanoparticles in vitro.

1. Dalargin, a Leu-enkephaline analogue, does normally not pass the blood-brain barrier (BBB). When it was adsorbed onto the surface of polybutylcyanoacrylate, nanoparticles dalargin can cross the BBB and induce central analgesic effects after intravenously as well as after oral application. 2. The mechanisms of this effect are unknown. Therefore, the authors evaluated whether neuronal transport was involved in this effect. In hippocampal synaptosomes and in tissue slices in vitro the active neuronal uptake and diffusion processes were determined by use of labelled D-aspartate as a marker of the aspartate/glutamate transporter and orotic acid as marker of diffusion. 3. Transporter-mediated uptake into hippocampal tissue preparations was not altered in comparison to control whereas diffusion processes were enhanced. These data indicate that the nanoparticles can modify neuronal uptake mechanisms.