Comparing zero-profile and conventional cage and plate in anterior cervical discectomy and fusion using finite-element modeling

Conventional cage and plate (CCP) implants usually used in ACDF surgery, do have limitations such as the development of postoperative dysphagia, adjacent segment degeneration, and soft tissue injury. To reduce the risk of these complications, zero-profile stand-alone cage were developed. We used finite-element modeling to compare the total von Mises stress applied to the bone, disc, endplate, cage and screw when using CCP and ZPSC implants. A 3-dimensional FE (Finite element) analysis was performed to investigate the effects of the CCP implant and ZPSC on the C3 ~ T1 vertebrae. We confirmed that the maximum von Mises stress applied with ZPSC implants was more than 2 times greater in the endplate than that applied with CCP implants. The 3D analysis of the ZPSC model von Mises stress measurements of screw shows areas of higher stress in red. Although using ZPSC implants in ACDF reduces CCP implant-related sequalae such as dysphagia, we have shown that greater von Mises stress is applied to the endplate, and screw when using ZPSC implants. This may explain the higher subsidence rate associated with ZPSC implant use in ACDF. When selecting an implant in ACDF, surgeons should consider patient characteristics and the advantages and disadvantages of each implant type.

Biomechanical Effects of Different Sitting Postures and Physiologic Movements on the Lumbar Spine: A Finite Element Study

This study used the finite element method(FEM) to investigate how pressure on the lumbar spine changes during dynamic movements in different postures: standing, erect sitting on a chair, slumped sitting on a chair, and sitting on the floor. Three load modes (flexion, lateral bending, and axial rotation) were applied to the FEM, simulating movements of the lumbar spine. Results showed no significant difference in pressure distribution on the annulus fiber and nucleus pulposus, representing intradiscal pressure, as well as on the cortical bone during movements between standing and erect sitting postures. However, both slumped sitting on a chair and sitting on the floor postures significantly increased pressure on the nucleus pulposus, annulus fibrosus, and cortical bone in all three movements when compared to standing or erect sitting on a chair. Notably, sitting on the floor resulted in even higher pressure on the nucleus pulposus and annulus fibers compared to slumped sitting on a chair. The decreased lumbar lordosis while sitting on the floor led to the highest increase in pressure on the annulus fiber and nucleus pulposus in the lumbar spine. In conclusion, maintaining an erect sitting position with increased lumbar lordosis during seated activities can effectively reduce intradiscal pressure and cortical bone stress associated with degenerative disc diseases and spinal deformities.

Rare or Overlooked Cases of Acute Acalculous Cholecystitis in Young Patients with Central Nervous System Lesion

This case series presents two cases of acute acalculous cholecystitis (AAC)-a rare condition-in young women with central nervous system (CNS) lesions. Both patients had significant neurologic deficits and no well-known risk factors or presence of comorbidities (such as diabetes or a history of cardiovascular or cerebrovascular disease). Early diagnosis is important in cases of AAC owing to its high mortality rate; however, due to neurological deficits in our cases, accurate medical and physical examinations were limited, thereby leading to a delay in the diagnosis. The first case was of a 33-year-old woman with multiple fractures and hypovolemic shock due to a traumatic accident; she was diagnosed with hypoxic brain injury. The second case was of a 32-year-old woman with bipolar disorder and early-onset cerebellar ataxia who developed symptoms of impaired cognition and psychosis; she was later diagnosed with autoimmune encephalopathy. In the first case, the duration between symptom onset and diagnosis was 1 day, but in the second case, it was 4 days from diagnosis based on the occurrence of high fever. We emphasize that if a young woman presents with high fever, the possibility of AAC should be considered, particularly if a CNS lesion is present because it may pose difficulty in the evaluation of typical symptoms of AAC. Careful attention is thus required in such cases.

Electrophysiologic Patterns of Symptomatic Vincristine-Induced Peripheral Neuropathy in Children with Acute Lymphocytic Leukemia

Acute lymphocytic leukemia is one of the most common cancers in children. Multi-drug chemotherapy is used for treatment, and the representative drug is vincristine. Although various side effects may occur due to vincristine, the association with peripheral neuropathy is high compared to that of other drugs. This study focused on children under the age of 18 years of age with ALL who received chemotherapy containing vincristine. We retrospectively analyzed the results of a nerve conduction study and a cumulative dose of vincristine in 30 children diagnosed with peripheral neuropathy. The average cumulative dose until diagnosis of vincristine-induced peripheral neuropathy was 14.99 ± 1.21 mg/m², and motor nerves were predominantly involved. Additionally, a marked decrease in average amplitude was also observed in motor nerves. In addition, when the relationship between the incidence of peripheral neuropathy and the cumulative dose was analyzed through the survival curve, about 50% of children developed peripheral neuropathy at a dose of 15.5 ± 1.77 mg/m². Based on the electrophysiological characteristics of pediatric vincristine-induced peripheral neuropathy, as well as the relationship between the incidence rate and the cumulative dose, it is possible to observe more closely the vincristine-induced peripheral neuropathy occurrence in children with ALL at an appropriate time.

Inhibitory effect of octyl-phenol and bisphenol A on calcium signaling in cardiomyocyte differentiation of mouse embryonic stem cells

Endocrine-disrupting chemicals (EDCs) have structures similar to steroid hormones and can interfere with hormone synthesis and normal physiological functions of reproductive organs. For example, sex steroid hormones influence calcium signaling of the cardiac muscle in early embryo development. To confirm the effect of progesterone (P4), octyl-phenol (OP), and bisphenol A (BPA) on early differentiation of mouse embryonic stem cells (mESCs) into cardiomyocytes, mESCs were treated with P4, OP, and BPA two days after attachment and media were replaced every two days. In addition, cells were treated with mifepristone (RU486), a synthetic steroid that has an affinity for progesterone receptor (Pgr), for one day starting on day 11. Beating ratio was decreased with P4, OP, and BPA treatment. The Pgr mRNA level was significantly increased in the P4-, OP- and BPA-treated groups. However, the mRNA level of the calcium channel gene (Trpv2), contraction-related genes (Ryr2, Cam2, and Mylk3) and cardiac development and morphogenesis genes (Rbp4, Ly6e, and Gata4) were significantly decreased in the P4-, OP-, and BPA-treated groups. Interestingly, treatment with RU486 rescued the altered calcium channel gene, contraction-related genes, and cardiac development and morphogenesis genes. P4, OP, and BPA treatments reduced the intracellular calcium level. Taken together, these results indicate that EDCs (OP and BPA) has a structure similar to that of endogenous steroid hormones such as progesterone and estrogen, and OP and BPA act like progesterone to inhibit and disrupt cardiomyocyte differentiation of mESCs.

Direct Detection of Akhiezer Damping in a Silicon MEMS Resonator

Silicon Microelectromechanical Systems (MEMS) resonators have broad commercial applications for timing and inertial sensing. However, the performance of MEMS resonators is constrained by dissipation mechanisms, some of which are easily detected and well-understood, but some of which have never been directly observed. In this work, we present measurements of the quality factor, Q, for a family of single crystal silicon Lamé-mode resonators as a function of temperature, from 80–300 K. By comparing these Q measurements on resonators with variations in design, dimensions, and anchors, we have been able to show that gas damping, thermoelastic dissipation, and anchor damping are not significant dissipation mechanisms for these resonators. The measured f · Q product for these devices approaches 2 × 10¹³, which is consistent with the expected range for Akhiezer damping, and the dependence of Q on temperature and geometry is consistent with expectations for Akhiezer damping. These results thus provide the first clear, direct detection of Akhiezer dissipation in a MEMS resonator, which is widely considered to be the ultimate limit to Q in silicon MEMS devices.

Orbital Engineering in Nickelate Heterostructures Driven by Anisotropic Oxygen Hybridization rather than Orbital Energy Levels

Resonant inelastic x-ray scattering is used to investigate the electronic origin of orbital polarization in nickelate heterostructures taking LaTiO_{3}-LaNiO_{3}-3×(LaAlO_{3}), a system with exceptionally large polarization, as a model system. We find that heterostructuring generates only minor changes in the Ni 3d orbital energy levels, contradicting the often-invoked picture in which changes in orbital energy levels generate orbital polarization. Instead, O K-edge x-ray absorption spectroscopy demonstrates that orbital polarization is caused by an anisotropic reconstruction of the oxygen ligand hole states. This provides an explanation for the limited success of theoretical predictions based on tuning orbital energy levels and implies that future theories should focus on anisotropic hybridization as the most effective means to drive large changes in electronic structure and realize novel emergent phenomena.

Engineered Unique Elastic Modes at a BaTiO_{3}/(2×1)-Ge(001) Interface

The strong interaction at an interface between a substrate and thin film leads to epitaxy and provides a means of inducing structural changes in the epitaxial film. These induced material phases often exhibit technologically relevant electronic, magnetic, and functional properties. The 2×1 surface of a Ge(001) substrate applies a unique type of epitaxial constraint on thin films of the perovskite oxide BaTiO_{3} where a change in bonding and symmetry at the interface leads to a non-bulk-like crystal structure of the BaTiO_{3}. While the complex crystal structure is predicted using first-principles theory, it is further shown that the details of the structure are a consequence of hidden phases found in the bulk elastic response of the BaTiO_{3} induced by the symmetry of forces exerted by the germanium substrate.

Intrinsic interfacial phenomena in manganite heterostructures

We review recent advances in our understanding of interfacial phenomena that emerge when dissimilar materials are brought together at atomically sharp and coherent interfaces. In particular, we focus on phenomena that are intrinsic to the interface and review recent work carried out on perovskite manganites interfaces, a class of complex oxides whose rich electronic properties have proven to be a useful playground for the discovery and prediction of novel phenomena.

Spatial expression of claudin family members in various organs of mice

Claudins (CLDNs) are tetraspan transmembrane proteins, which are components of tight junctions. The CLDN family is composed of 27 members that are responsible for paracellular transport and certain CLDNs form charge-selective ion channels. CLDNs have two extracellular loops, and the charge of the first extracellular loop determines the ion selectivity of each CLDN. Although the expression and function of each CLDN have been previously investigated, the distribution of CLDNs in various target organs remains to be determined. In the present study, the tissue-specific mRNA distribution of CLDNs (1-5, 7-8, 10a and b, 11-12, 14-17 and 19) in the duodenum, ileum, colon, kidney, liver and lung were defined. Among the tested CLDNs, CLDN1, 2, 12 and 16 were selected for further investiagtion. It was observed that CLDN1, CLDN2 and CLDN12 transcripts and proteins were particularly abundant in the investigated organs. Notably, immune-reactive CLDN16 was detected in a tissue-specific manner and shown in the renal tubules and portal vein. The tested CLDNs were localized to intercellular apical junctions in the epithelium of the intestine, renal tubule and bronchus. Based on this novel information, the presence of several types of CLDNs is of interest as CLDNs may promote or dampen the paracellular diffusion of specific ions.

Examining graphene field effect sensors for ferroelectric thin film studies

We examine a prototype graphene field effect sensor for the study of the dielectric constant, pyroelectric coefficient, and ferroelectric polarization of 100-300 nm epitaxial (Ba,Sr)TiO3 thin films. Ferroelectric switching induces hysteresis in the resistivity and carrier density of n-layer graphene (n = 1-5) below 100 K, which competes with an antihysteresis behavior activated by the combined effects of electric field and temperature. We also discuss how the polarization asymmetry and interface charge dynamics affect the electronic properties of graphene.

Gene expression profiling of a cold-shocked earthworm Eisenia andrei

To identify genes that are modulated under cold-stress conditions in the earthworm Eisenia andrei, we performed a genome-wide analysis of gene expression in cold-shocked earthworms by using Serial Analysis of Gene Expression (SAGE). We identified 5,977 and 5,407 unique SAGE tags under normal and cold-stressed conditions, respectively. The majority of the SAGE tags did not match to any known expressed sequences, due to a paucity of expression data in earthworms. We converted the statistically significant SAGE tags for the cold-stressed condition into expressed sequence tags (ESTs), and the results showed that particular genes associated with energy homeostasis, cellular defense mechanisms, and ion balance were up-regulated or down-regulated. We constructed a regulatory network of some of these genes and identified rps-6 as a core gene in the cold-response regulatory-gene network. Our data provide a baseline for gene expression studies of cold shock in the Lumbricidae.

Dynamic evanescent phonon coupling across the La(1-x)Sr(x)MnO3/SrTiO3 interface

The transport and magnetic properties of correlated La0.53Sr0.47MnO3 ultrathin films, grown epitaxially on SrTiO3, show a sharp cusp at the structural transition temperature of the substrate. Using a combination of experiment and first principles theory we show that the cusp is a result of evanescent cross-interface coupling between the charge carriers in the film and a soft phonon mode in the SrTiO3, mediated through linked oxygen octahedral motions. The amplitude of the mode diverges at the transition temperature, and phonons are launched into the first few atomic layers of the film, affecting its electronic state.

Device performance of ferroelectric/correlated oxide heterostructures for non-volatile memory applications

Ferroelectric field effect devices offer the possibility of non-volatile data storage. Attempts to integrate perovskite ferroelectric materials with silicon semiconductors, however, have been largely unsuccessful in creating non-volatile, nondestructive read memory elements because of difficulties in controlling the ferroelectric/semiconductor interface. Correlated oxide systems have been explored as alternative channel materials to form all-perovskite field effect devices. We examine a non-volatile memory using an electric-field-induced metal-insulator transition in PbZr(0.2)Ti(0.8)O(3)/La(1 - x)Sr(x)MnO(3) (PZT/LSMO), PZT/La(1 - x)Ca(x)MnO(3) (PZT/LCMO) and PZT/La(1 - x)Sr(x)CoO(3) (PZT/LSCO) devices. The performance of these devices in the areas of switching time and retention are discussed.

Development of polymer lab-on-a-chip (LOC) for oxidation-reduction potential (ORP) measurement

Reverse osmosis (RO) desalination has been recognized as a promising method to solve the water shortage problem. Nevertheless, since it is energy intensive and has many problems associated with biofouling/fouling of RO membranes in RO plants, its commercial acceptance is still slow. Especially, as high levels of oxidizing agents negatively affect RO membrane efficiency and life span. So, there is a need to develop sensitive, selective, portable and rapid methods to determine oxidation-reduction potential (ORP) in feed solution. For developing a polymer ORP lab-on-a-chip (LOC), a microchannel patterned on a polymer substrate was successfully filled with 800 nm diameter silica beads using self-assembly bead packing technology. The measured ORPs using the three kinds of redox potential solutions were typically slightly lower than those of the nominal redox potential. But, all of the measurements should be deemed acceptable. The ORP LOC has also a much shorter response time than the conventional potentiometric sensor.

Interface-induced polarization and inhibition of ferroelectricity in epitaxial SrTiO₃/Si

We use SrTiO₃/Si as a model system to elucidate the effect of the interface on ferroelectric behavior in epitaxial oxide films on silicon. Using both first-principles computations and synchrotron x-ray diffraction measurements, we show that structurally imposed boundary conditions at the interface stabilize a fixed (pinned) polarization in the film but inhibit ferroelectric switching. We demonstrate that the interface chemistry responsible for these phenomena is general to epitaxial silicon-oxide interfaces, impacting on the design of silicon-based functional oxide devices.

Origin of the magnetoelectric coupling effect in Pb(Zr0.2Ti0.8)O{3}/La{0.8}Sr{0.2}MnO{3} Multiferroic heterostructures

The electronic valence state of Mn in Pb(Zr0.2Ti0.8)O{3}/La{0.8}Sr{0.2}MnO{3} multiferroic heterostructures is probed by near edge x-ray absorption spectroscopy as a function of the ferroelectric polarization. We observe a temperature independent shift in the absorption edge of Mn associated with a change in valency induced by charge carrier modulation in the La0.8Sr0.2MnO3, demonstrating the electronic origin of the magnetoelectric effect. Spectroscopic, magnetic, and electric characterization shows that the large magnetoelectric response originates from a modified interfacial spin configuration, opening a new pathway to the electronic control of spin in complex oxide materials.

High-mobility few-layer graphene field effect transistors fabricated on epitaxial ferroelectric gate oxides

The carrier mobility mu of few-layer graphene (FLG) field-effect transistors increases tenfold when the SiO2 substrate is replaced by single-crystal epitaxial Pb(Zr0.2Ti0.8)O3 (PZT). In the electron-only regime of the FLG, mu reaches 7x10(4) cm(2)/V s at 300 K for n=2.4x10(12)/cm(2), 70% of the intrinsic limit set by longitudinal acoustic (LA) phonons; it increases to 1.4x10(5) cm(2)/V s at low temperature. The temperature-dependent resistivity rho(T) reveals a clear signature of LA phonon scattering, yielding a deformation potential D=7.8+/-0.5 eV.

Atomic structure of the epitaxial BaO/Si(001) interface

We present the structure of the interface responsible for epitaxy of crystalline oxides on silicon. Using synchrotron x-ray diffraction, we observe a 2 x 1 unit cell reconstruction at the interface of BaO grown on Si(001) terminated with 1/2 ML of Sr. Since this symmetry is not present in bulk BaO or Si, only the interface contributes to diffracted intensity. First principles calculations accurately predict the observed diffraction and identify the structure of the BaO/Si interface, including the elemental composition and a sub-A rumpling due to epitaxial strain of the 7 adjacent BaO and Si layers.

Development of a portable analyzer with polymer lab-on-a-chip (LOC) for continuous sampling and monitoring of Pb(II)

A new portable analyzer with polymer lab-on-a-chip (LOC) has been designed, fabricated and fully characterized for continuous sampling and monitoring of lead (Pb(II)) in this work. As the working electrodes of the sensor, bismuth (Bi (III)) which allowed the advantage of being more environmentally friendly than traditional mercury drop electrodes was used, while maintaining similar sensitivity and other desirable characteristics. The size of a portable analyzer was 30 cmx23 cmx7 cm, and the weight was around 3 kg. The small size gives the advantage of being portable for field use while not sacrificing portability for accuracy of measurement. Furthermore, the autonomous system developed in coordination with the development of new polymer LOC integrated with electrochemical sensors can provide an innovative way to monitor surface waters in an efficient, cost-effective and sustainable manner.

Role of strontium in oxide epitaxy on silicon (001)

Epitaxial oxide-Si heterostructures, which integrate the functionality of crystalline oxides with Si technology, are made possible by a submonolayer of Sr deposited on Si (001). We find by electron diffraction studies using single termination Si wafers that this Sr submonolayer replaces the top layer of Si when deposited at 650 degrees C. Supported by first-principles calculations, we propose a model for the reaction dynamics of Sr on the Si surface and its effect on oxide epitaxy. This model predicts, and we experimentally confirm, an unexplored 25 degrees C pathway to crystalline oxide epitaxy on Si.

Appearance of novel G-bacteria belonging to acidobacteria in a dairy wastewater treatment plant

A dairy wastewater treatment plant operates a sequencing batch reactor (SBR) and stimulates enhanced biological phosphorus removal (EBPR) process with alternating anaerobic and aerobic cycles. Occasionally, the plant suffers from a high suspended solids problem in the supernatant. Interestingly, the occurrence of high suspended solids coincided with times when the EBPR process failed to remove phosphorus. To find out if there was a relationship between the EBPR failure and the high suspended solids problem, effluent samples were collected from the site during the period of poor phosphorus removal and examined microscopically. It was found that cocci-shaped bacteria (3-4 microm in diameter) were abundant in the effluent samples and they were clustered in tetrads. These were believed to be G-bacteria and results of both Gram and Neisser staining tests were negative, suggesting that they had few intracellular polyphosphate granules. Using polymerase chain reaction (PCR), cloning and deoxyribonucleic acid (DNA) sequence analysis, the phylogenetic information of in situ G-bacteria was obtained. It was found that all of the recovered clones were clustered in the phylum of Acidobacteria.

Functional and genetic assessment of IFN-gamma receptor in patients with clinical tuberculosis

OBJECTIVE

The molecular basis of the genetic vulnerability underlying the most common form of clinical tuberculosis (TB) remains largely unknown. We speculated that mild genetic defects in the interferon-gamma (IFN-gamma) signalling pathway caused a subtle functional impairment of IFN-gamma which would explain susceptibility to Mycobacterium tuberculosis in clinical TB.

DESIGN

A case-control study.

RESULTS

We evaluated functional responsiveness to IFN-gamma in monocytes from patients with clinical TB (n = 10), and analysed the genetic sequences of the IFN-gamma receptor 1 (IFN-gammaR1) and STAT1 genes in patients with disseminated TB (n = 18). IFN-gamma stimulated an increase in the expression of HLA-DR and CD64 on monocytes of both controls and patients; the rate of increase in expression was the same in both groups. Treatment with IFN-gamma before lipopolysaccharide (LPS) stimulation further increased tumour necrosis factor-alpha (TNF-alpha) production as compared to TNF-alpha production with LPS stimulation alone; the rate of increase in TNF-alpha production was the same in both groups. The known mutations in the coding sequences of the IFN-gammaR1 and STAT1 genes were not found in the patients with disseminated tuberculosis.

CONCLUSION

These results suggest that impairment of the IFN-gamma signalling pathway did not account for cases of clinical TB in this study.

Ferroelectricity at the Nanoscale: Local Polarization in Oxide Thin Films and Heterostructures

Ferroelectric oxide materials have offered a tantalizing potential for applications since the discovery of ferroelectric perovskites more than 50 years ago. Their switchable electric polarization is ideal for use in devices for memory storage and integrated microelectronics, but progress has long been hampered by difficulties in materials processing. Recent breakthroughs in the synthesis of complex oxides have brought the field to an entirely new level, in which complex artificial oxide structures can be realized with an atomic-level precision comparable to that well known for semiconductor heterostructures. Not only can the necessary high-quality ferroelectric films now be grown for new device capabilities, but ferroelectrics can be combined with other functional oxides, such as high-temperature superconductors and magnetic oxides, to create multifunctional materials and devices. Moreover, the shrinking of the relevant lengths to the nanoscale produces new physical phenomena. Real-space characterization and manipulation of the structure and properties at atomic scales involves new kinds of local probes and a key role for first-principles theory.

Electric field effect in correlated oxide systems

Semiconducting field-effect transistors are the workhorses of the modern electronics era. Recently, application of the field-effect approach to compounds other than semiconductors has created opportunities to electrostatically modulate types of correlated electron behaviour--including high-temperature superconductivity and colossal magnetoresistance--and potentially tune the phase transitions in such systems. Here we provide an overview of the achievements in this field and discuss the opportunities brought by the field-effect approach.

Electrostatic tuning of the hole density in NdBa2Cu3O(7-delta) films and its effect on the Hall response

We have used the ferroelectric field effect in heterostructures based on superconducting NdBa2-Cu(3)O(7-delta) and ferroelectric Pb(Zr0.2Ti0.8)O3 to electrostatically modulate in a reversible and nonvolatile fashion the hole carrier density of the superconducting layer. Reversing the ferroelectric polarization induces a constant relative change in the resistivity and Hall constant of 9% and 6%, respectively, at all temperatures above the superconducting transition. The cotangent of the Hall angle displays a T2 dependence with a slope that increases as the carrier density is reduced.

Fluorogenic assay for beta-glucuronidase using microchip-based capillary electrophoresis

Microchip capillary electrophoresis (CE) was used with a model enzyme assay to demonstrate its potential application to combinatorial drug screening. Hydrolysis with beta-glucuronidase of the conjugated glucuronide, fluorescein mono-beta-D-glucuronide (FMG), liberated the fluorescent product, fluorescein. FMG and fluorescein were detected by fluorescence, with excitation and emission at 480 and 520 nm, respectively. Microchip CE was used to separate FMG and fluorescein. Fluorescein production was monitored to assess beta-glucuronidase activity. Michaelis-Menten enzyme kinetics analysis yielded the Km value. The results were compared with those from experiments done by conventional CE. The Km value for beta-glucuronidase with FMG is being reported for the first time as 18 microM. The inhibition of beta-glucuronidase by the competitive inhibitor D-saccharic acid-1,4-lactone (SL) was also determined using microchip CE. Reactions were done with various concentrations of inhibitor and constant beta-glucuronidase and FMG concentrations. A dose-response plot was acquired and the IC50 value for SL was determined to be 3 microM.

Clinical Analysis of PTEN, p53 and Her-2/neu Expressions in Thyroid Cancers

PURPOSE

The dual-specificity phosphatase PTEN/ MMAC1/TEP1 has recently been identified as the tumor suppressor gene most frequently mutated and/or deleted in human tumors. However, PTEN mutations have rarely been detected in sporadic thyroid cancers. Therefore, this study investigated the PTEN expression of thyroid cancer and the relationship between PTEN, clinical status and other biologic factors such as HER-2/neu and p53.

MATERIALS AND METHODS

The study samples consisted of 62 thyroid cancer specimens and 24 benign thyroid tumor specimens from patients who were operated on the Department of Surgery, Uijongbu St. Mary's hospital during the 5 years from January 1995 until January 2000. All tumors were studied by immunohistochemical staining using monoclonal antibodies against PTEN, HER-2/neu and p53. The results were analyzed statistically.

RESULTS

PTEN protein was found to be under-expressed more frequently in thyroid cancers (29%) than in benign thyroid tumors (4.2%). The reduction in PTEN expression in thyroid cancers was not significantly related with the recorded clinical factors such as size, age, lymph node metastasis and p53, except for HER-2 which was found to be significantly related (p=0.001). HER-2 over- expression was noted in thyroid cancer (83.8%) more frequently than in benign tumors (16.7%).

CONCLUSION

This study has demonstrated that the under-expression of PTEN protein and the over-expression of HER-2 protein may play a role in the carcinogenesis and development of thyroid cancer.

Low mutational burden of individual acquired mitochondrial DNA mutations in brain

Neurons may be particularly susceptible to oxidative damage, which has been proposed to induce somatic mutations, particularly in mitochondrial DNA (mtDNA). Therefore, acquired mtDNA mutations might preferentially accumulate in the brain and could play a role in aging and neurodegenerative disorders. Recently, a somatic T to G mtDNA mutation at noncoding nucleotide position 414 was reported in fibroblasts specifically from elderly subjects, with mutational burdens of up to 50%. We screened for this mutation in brain-derived mtDNA from 8 Alzheimer's disease patients, 27 Parkinson's disease patients, 4 multiple system atrophy patients, and 44 controls using up to three RFLP analyses. A total of 73 of these subjects were over the age of 65. The 414 mutation was absent in all cases. Next, individual mtDNA fragments from 6 elderly subjects were cloned, and a total of 70 clones were sequenced. The 414 mutation was absent in all clones, though occasional sequence variations were identified at other sites in single clones. The 414 mutation also was absent in blood (n = 6) and fibroblasts (n = 11) from elderly subjects. Our data suggest that it is rare for any one particular acquired mtDNA mutation to reach levels in the brain that are functionally significant. This does not exclude the possibility that the cumulative burden of multiple, individually rare, acquired mutations impairs mitochondrial function.

An on-chip magnetic bead separator using spiral electromagnets with semi-encapsulated permalloy

A new planar bio-magnetic bead separator on a glass chip has been designed, fabricated and tested. The separator is composed of micromachined semi-encapsulated spiral electromagnets and fluid channels, which have been separately fabricated and then bonded. The device was tested with super-paramagnetic beads of mean diameter 1 microm which were suspended in a buffered solution. When a DC current of 300 mA was applied to the inductor, the bio-magnetic beads were successfully separated on the electromagnets, showing a functional capability as a magnetic bead separator. To evaluate separation rate and capability, the inductance measurement method has been introduced and the inductance variation according to the separation rate has been characterized. Using this separator, cells or cell fragments and magnetic beads bonded with protein or enzyme suspended in bio-buffer solutions can be successfully separated from their suspensions, envisaging a filterless bio-separator.

A clinical analysis of gasless endoscopic thyroidectomy

Gasless endoscopic surgery was applied to a thyroidectomy. Compared with the previous method of endoscopic thyroidectomy, this method is superior in obtaining hemostasis and minimizing the possible complications of gas-insufflating surgery, such as a hypercapnia or massive subcutaneous emphysema. We successfully removed 37 thyroid tumors in 35 patients by gasless endoscopic surgery without any significant complications. No scars remained in the neck, and all patients were satisfied with the cosmetic results. Gasless endoscopic thyroidectomy is a safe and technically feasible alternative to conventional thyroidectomy for cases of benign thyroid tumors and has good cosmetic results.

Real-time full-color three-dimensional display with a micromirror array

We designed, realized, and tested what is believed to be the first real-time, full-color, autostereoscopic three-dimensional (3-D) display with a micromirror array. Compared with the diffractive partial pixel architecture [Opt. Lett. 20, 1418 (1995)], this approach has certain advantages:(1) Micromirrors are reflective and thus achromatic (panchromatic) and (2) a variety of displays can be used as the image source. We used backlit transparencies to test the system and then used an ordinary color CRT to show several computer-generated full-color 3-D animations.

Electrostatic modulation of superconductivity in ultrathin GdBa2Cu3O7-x films

The polarization field of the ferroelectric oxide lead zirconate titanate [Pb(ZrxTi1-x)O3] was used to tune the critical temperature of the hightemperature superconducting cuprate gadolinium barium copper oxide (GdBa2Cu3O7-x) in a reversible, nonvolatile fashion. For slightly underdoped samples, a uniform shift of several Kelvin in the critical temperature was observed, whereas for more underdoped samples, an insulating state was induced. This transition from superconducting to insulating behavior does not involve chemical or crystalline modification of the material.

Regulatory considerations for preclinical development of anticancer drugs

The entry of new anticancer treatments into phase I clinical trials is ordinarily based on relatively modest preclinical data. This report defines the battery of preclinical tests important for assessing safety under an Investigational New Drug application (IND) and outlines a basis for extrapolating starting doses of investigational anticancer drugs in phase I clinical trials from animal toxicity studies. Types of preclinical studies for the support of marketing of a new anticancer drug are also discussed. This report addresses differences and similarities in the preclinical development of cytotoxic drugs (including photosensitizers and targeted delivery products), drugs used chronically (chemopreventive drugs, hormonal drugs, immunomodulators), and drugs intended to enhance the efficacy (MDR-reversing agents and radiation/chemotherapy sensitizers) or diminish the toxicity of currently used anticancer therapies. Factors to consider in the design of preclinical studies of combination therapies, alternative therapies, and adjuvant therapies in the treatment of cancer, and to support changes in clinical formulations or route of administration, are also discussed.

Chemosensitizing activity of caffeic acid in multidrug-resistant MCF-7/Dox human breast carcinoma cells

The chemosensitizing activity of caffeic acid was examined in parent MCF-7 and multidrug-resistant MCF-7/Dox human breast carcinoma cells. In clonogenic assays, MCF-7/Dox cell was about 135-fold less sensitive to doxorubicin than MCF-7 cells. Caffeic acid (10 microM) slightly altered the colony-forming ability of MCF-7 cells, and markedly reduced the IC50 of doxorubicin (Dox) from 10.8 +/- 1.3 microM to 0.83 +/- 0.21 microM in MCF-7/Dox cells. When compared to MCF-7/Dox cells, intracellular accumulations of [14C] Dox in MCF-7 cells for 1 hour and 12 hours were elevated 2.3-fold and about 6.4-fold, respectively. Doxorubicin accumulations in MCF-7 and MCF-7/Dox cells were not altered in the presence of 10 microM caffeic acid. Both TGF beta 1 and TGF beta 2 isotypes were detected in MCF-7/Dox cells, while only TGF beta 1 was found in MCF-7 cells. The level of TGF beta 1 in MCF-7/Dox cells was about 3-fold greater than that in MCF-7 cells. In cells pretreated with caffeic acid (10 microM), TGF beta 1 and TGF beta 2 levels were overexpressed only in MCF-7/Dox cells by 90% and 60%, respectively. These results suggest that caffeic acid is potentially a chemosensitizing agent with greater selectivity to drug-resistant MCF-7/Dox cells over parent MCF-7 cells and that the chemosensitizing effect is not mediated by altered drug concentrations in the cells, but may be possibly correlated to the induction of TGF beta isotypes.

Considerations for toxicology studies of respiratory drug products

The standard approaches for the preclinical development of chronically administered drugs also apply to most respiratory drugs. Modifications from the standard preclinical development plan, however, may be necessary if the drug is administered intranasally or by inhalation. Administration by these routes may result in airway toxicity and the intended patient population is often particularly susceptible. Current and former representatives of the Division of Pulmonary Drug Products (CDER, U.S. FDA) present this article to describe general principles of preclinical development for respiratory drug indications. The article addresses drugs intended for administration by the intranasal or inhalation routes. The article describes the types of studies recommended, considers the initial human dose, and discusses dose-escalation strategies in clinical trials. Other areas of special concern with intranasal or inhalation administration include immunotoxicity, reproductive toxicity, types of dosing apparatus, excipients and extractables, and formulation changes. The approaches described in this article are intended as general information and should be adapted to the scientific considerations and circumstances of a particular drug under development.

Selective inhibition of the effects of phorbol ester on doxorubicin resistance and P-glycoprotein by the protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7) in multidrug-resistant MCF-7/Dox human breast carcinoma cells

The possible regulation of the multidrug-resistant (MDR) phenotype and P-glycoprotein by protein kinase C (PKC) was investigated in the doxorubicin (Dox)-resistant MCF-7 cell line (MCF-7/Dox). In a clonogenic assay, cells exposed to 100 nM phorbol 12-myristate 13-acetate (PMA) for 1 hr were about 3-fold more resistant to Dox than were cells exposed to Dox alone. The PKC inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7, 30 microM) completely blocked the PMA-induced effect, but did not reverse the MDR phenotype. Complete down-regulation of PKC from MCF-7/Dox cells by 24-hr preincubation with PMA did not alter the degree of Dox resistance. Intracellular accumulation of [14C]Dox decreased from a baseline of 28 pmol/10(6) cells to 15 pmol/10(6) cells in the presence of 100 nM PMA. The reduced Dox accumulation in the presence of PMA was not blocked by pretreatment of cells with H7. Following a 24-hr pretreatment with PMA, the cells accumulated almost equal amounts of [14C]Dox in the absence or presence of PMA. Cells from PMA-treated colonies showed significantly higher levels of expression of P-glycoprotein when compared with those from control colonies. H7 did not affect the basal level of P-glycoprotein in cells from control colonies or PMA-induced overexpression of P-glycoprotein in cells from PMA-treated colonies. Upon stimulation with PMA (100 nM), PKC alpha and beta translocated to the cell membrane and nucleus and PKC delta and epsilon to the perinuclear membrane and the nucleus, respectively. H7 (30 microM) completely inhibited PMA-induced translocations of PKC delta and epsilon, whereas it only partially blocked the translocations of PKC alpha and beta. These results suggest that PMA appears to alter Dox resistance and intracellular Dox accumulation in a PKC-dependent manner and to induce increased expression of P-glycoprotein in MCF-7/Dox cells. Differential effects of H7 on the PMA-induced changes suggest that different isoforms of PKC may be involved in cell growth and drug accumulation processes as well as P-glycoprotein expression.

Effect of combination of suboptimal concentrations of P-glycoprotein blockers on the proliferation of MDR1 gene expressing cells

Pharmacologically active in vivo doses of P-glycoprotein (Pgp) blockers, specifically verapamil, Cremophor EL and PSC833 cause toxicity in addition to that from the concomitantly used cancer chemotherapeutic drugs. It was shown before that these blockers cause different types of toxicities in vivo. We found that these 3 chemically distinct Pgp blockers exert different biophysical effects on the membranes of L1210 MDR cells. They also affect the general metabolism of these cells differently, but all block affinity labeling of Pgp. We could also show that the combination of suboptimal doses of these blockers can restore the uptake of the Pgp substrate rhodamine 123 into L1210MDR, 3T3MDR and KB-VI cells and can reduce the survival rate of these cells when treated in combination with daunorubicin. Our results suggest that the combination of suboptimal doses of these Pgp blockers may be advantageous in clinical practice.

Ferroelectric Field Effect in Epitaxial Thin Film Oxide SrCuO 2 /Pb(Zr 0.52 Ti 0.48 )O 3 Heterostructures

A ferroelectric field effect in epitaxial thin film SrCuO(2)/Pb(Zr(0.52)Ti(0.48))O(3) heterostructures was observed. A 3.5 percent change in the resistance of a 40 angstrom SrCuO(2) layer (a parent high-temperature superconducting compound) was measured when the polarization field of the Pb(Zr(0.52)Ti(0.48))O(3) layer was reversed by the application of a pulse of small voltage (<5 volts). This effect, both reversible and nonvolatile, is attributed to the electric field-induced charge at the interface of SrCuO(2) and Pb(Zr(0.52)Ti(0.48))O(3). This completely epitaxial thin film approach shows the possibility of making nonvolatile, low-voltage ferroelectric field effect devices for both applications and fundamental studies of field-induced doping in novel compounds like SrCuO(2).

Effect of 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) on HSP70 and HSP28 gene expression and thermotolerance development in human colon carcinoma cells

The effect of 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), a potent protein kinase C (PKC) inhibitor, on the development of thermotolerance and expression of heat shock genes (HSP70 and HSP28) was investigated in human colon carcinoma HT-29 cells. After acute heating at 45 degrees for 15 min, cells became resistant to a challenge heat shock. The development of thermotolerance was suppressed by adding H-7 after heat shock. Northern blots show that the levels of HSP70 and HSP28 mRNA increased rapidly and reached maximal values within 6 hr. H-7 suppressed the accumulation of HSP70 and HSP28 mRNA as well as their protein synthesis, and the level of suppression was concentration dependent. However, little effect was observed if the drug was added 1 hr before and during heat shock. These results suggest that PKC is involved in the regulation of heat shock gene expression after acute heat shock.

Rifampin-resistant Mycobacterium kansasii

We identified 36 rifampin-resistant Mycobacterium kansasii isolates, including 17 (4%) of 464 isolates recovered in Texas between 1989 and 1992. Of 29 patients infected with rifampin-resistant M. kansasii whose history of medication was known, 90% had previously received rifampin, and 58% of these patients had been treated with one or two effective drugs. Thirty-two percent of rifampin-resistant isolates recovered since 1989 were from patients who were seropositive for human immunodeficiency virus (HIV) infection. Twenty courses of therapy with a four-drug regimen determined on the basis of in vitro susceptibilities were administered to 16 patients from whom rifampin-resistant isolates were recovered; the therapy did not include surgery. Sputum cultures converted to negative as the result of 90% of treatments (time to conversion: mean, 11 weeks; range, 4-20 weeks). Bacteriologic relapses occurred in four of five patients who withdrew from therapy after being culture negative for < or = 6 months of therapy and in one of 12 patients who were culture negative for at least 12 months of therapy (mean, 16.3 months). This study suggests that the prognosis for cure of infection due to rifampin-resistant M. kansasii with chemotherapy alone is excellent, although the number of cases appears to be increasing, in part because of the HIV disease epidemic.

Regulatory considerations for oligonucleotide drugs: updated recommendations for pharmacology and toxicology studies

This article describes pharmacology and toxicity studies for oligonucleotide drugs that are recommended for inclusion in the initial Investigational New Drug Application (IND), a first request to use an investigational drug in clinical trials. Recent observations of non-sequence-dependent cardiovascular toxicity and deaths in monkeys following intravenous infusions of phosphorothioates have raised a potential safety concern for oligonucleotide drugs. This concern should be considered by drug sponsors in designing pre-IND nonclinical development programs and Phase I clinical protocols. Pre-IND conduct of pharmacodynamic cardiovascular screening is highly recommended for defining safe clinical dosing regimens for phosphorothioate (and, possibly, other charged-backbone) oligomers. Additionally, drug sponsors are encouraged to (1) conduct research into-the mechanisms responsible for this dose-limiting toxicity, (2) institute liberal publication policies for research conducted under industrial sponsorship, and (3) communicate with reviewing divisions at FDA for updated guidance in this field when planning pre-IND safety studies. Recommendations for nonclinical studies during development of oligonucleotides will be modified as new information regarding the biological properties of oligonucleotides becomes available.

Regulatory considerations for evaluating the pharmacology and toxicology of antisense drugs

This article focuses on pharmacology and toxicology data that should be included in an Investigational New Drug Application (IND), a request to use an investigational drug in clinical trials. In general, pharmacology and toxicology testing programs for antisense compounds are held to the same regulatory standards applied to other new therapeutic classes. Biological properties of oligonucleotide therapeutics are mentioned where they may pertain to clinical safety issues. Nonclinical data submitted to the IND should characterize the pharmacology, disposition, and toxicology of a new drug; these data form the basis for clinical risk assessment. Concomitant evaluation of pharmacokinetics allows for better interpretation of in vivo studies and increased accuracy of dose extrapolation to humans. Recommendations for nonclinical drug development will be modified as new information regarding the biological properties of oligonucleotides becomes available.

Stereostructure activity relationships of catecholamines on human platelet function

The concentration-dependent effects of clonidine, isomers of epinephrine, norepinephrine (NE), isoproterenol, cobefrin and alpha-methyldopamine, and related desoxy analogs (epinine, dopamine, N-isopropyldopamine) were examined on human platelets. The rank order of aggregatory potency (pD2 values) was R(-)-epinephrine (6.3) greater than R(-)-NE (5.9) greater than (+/-)-erythro-cobefrin (5.3) greater than S(+)-epinephrine (4.7) = S(+)-NE (4.7) = clonidine (4.7) = dopamine (4.6) greater than epinine (4.4) greater than S(+)-alpha-methyldopamine (4.3) = R(-)-alpha-methyldopamine (4.3) greater than (+/-)-threo-cobefrin (3.7). The isoproterenol isomers and N-isopropyl-dopamine were inactive as agonists. In 9 of 16 platelet-rich plasma preparations, R(-)-epinephrine, R(-)-NE, and (+/-)erythro-cobefrin were agonists and the remaining analogs blocked R(-)-NE-induced aggregation with a rank order of inhibitory potencies (pKB values) of clonidine (6.2) greater than S(+)-alpha-methyldopamine (5.0) greater than dopamine (4.6) = R(-)-alpha-methyldopamine (4.4) greater than or equal to S(+)-NE (4.3) greater than N-isopropyldopamine (4.1) greater than S(+)-isoproterenol (3.7) = R(-)-isoproterenol (3.5). Each compound was also able to reverse prostaglandin E1 (PGE1) (0.1 microM)-induced blockade of the maximal aggregation response to ADP. At high concentrations, R(-)-isoproterenol was more potent than either the S(+)-isomer or desoxy analog, N-isopropyldopamine, in the reversal of PGE1 inhibition of ADP aggregation. Phentolamine blocked these alpha 2-adrenoceptor-mediated actions against PGE1 on ADP aggregation. The rank order of potency for the reversal of PGE1-mediated inhibition of ADP aggregation by these catecholamines was similar to that observed for platelet aggregation. Our results indicate that (i) the stereochemical requirements for the interaction of catecholamines with platelet alpha 2-adrenoceptors are in agreement with the Easson-Stedman hypothesis and other alpha-adrenoceptor tissues; (ii) catecholamines lacking a benzylic hydroxyl group in the R-configuration and/or possessing an N-isopropyl group were alpha 2-adrenoceptor antagonists; (iii) clonidine gave quantitatively different responses compared with catecholamines for interaction with alpha 2-adrenoceptors; and (iv) inhibition of platelet adenylate cyclase is correlated to the inhibition of epinephrine-induced aggregation response for this series of compounds.

Differential effects of phorbol ester on the in vitro invasiveness of malignant and non-malignant human fibroblast cells

The effect of the phorbol ester tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) on cell invasion was studied using an in vitro assay for cell invasion through a reconstituted basement membrane matrix (Matrigel). TPA inhibited the invasiveness of malignant human fibrosarcoma HT1080 cells. In contrast, WI-38 lung fibroblasts, which show a very low invasive capacity, were stimulated (3-fold) to invade Matrigel after exposure to TPA for 48 hours. The inhibitory or stimulatory effects of TPA on cell invasion were correlated with a decrease or an increase in cell motility and collagenase IV activity, respectively. Synthetic diacylglycerols partially mimicked the inhibitory action of TPA on HT1080 cells but failed to stimulate WI-38 cell invasion. Immunoblots demonstrated that in both cell lines the alpha and beta isoforms of protein kinase C were equally down-regulated after a 5 hour exposure to TPA despite the basal low level of protein kinase C polypeptide in the malignant cells. Thus, whereas in WI-38 cells induction of an invasive behavior could be observed in the absence of protein kinase C, in the malignant cells disappearance of the kinase was associated with a non-invasive phenotype.

Characterization of the inhibition of U46619-mediated human platelet activation by the trimetoquinol isomers. Evidence for endoperoxide/thromboxane A2 receptor blockade

Sites of inhibition for the trimetoquinol (TMQ) isomers on 15S-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5Z,13E-dienoic acid (U46619)-, 12-O-tetradecanoylphorbol 13-acetate (TPA)- and A23187-induced human platelet activation were investigated. Experiments using washed human platelets were designed to characterize relationships among functional (aggregation, secretion) and biochemical (protein phosphorylation, metabolism of inositol phospholipids and radioligand displacement analysis) processes of platelet activation by U46619 and the specificity of inhibition by the TMQ isomers. Thromboxane A2 receptor stimulation by U46619 in human platelets resulted in a time- and concentration-dependent breakdown of inositol phospholipids [phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidylinositol 4-monophosphate (PIP), and phosphatidylinositol (PI)], phosphatidic acid (PA) accumulation, phosphorylation of 20 and 45 kD proteins, aggregation and serotonin secretion. The TMQ isomers stereoselectively inhibited all U46619-mediated platelet activation processes. R(+)-TMQ was 40- and 22-fold more potent than S(-)-TMQ as an inhibitor of U46619-induced platelet aggregation and serotonin secretion respectively. In addition, R(+)-TMQ blocked U46619-induced 20 kD protein phosphorylation, 45 kD protein phosphorylation, PIP2, PIP and PI breakdown, and PA accumulation with a potency which was 8-, 13-, 45-, 37-, 33- and 33-fold greater than the S(-)-isomer respectively. In contrast to S(-)-TMQ, R(+)-TMQ produced a concentration-dependent inhibition of specific [3H]U46619 binding to endoperoxide/thromboxane A2 receptor sites in washed platelets. In other experiments, S(-)-TMQ was more potent than R(+)-TMQ as an inhibitor of TPA- and A23187-induced platelet aggregation and serotonin secretion, and of TPA-induced phosphorylation of 45 and 20 kD proteins. The inhibitory potencies of S(-)-TMQ against TPA- or A23187-induced responses were similar to those needed for antagonism of U46619-mediated platelet activation. In contrast, much higher concentrations of R(+)-TMQ were required for blockade of TPA or A23187 versus U46619-mediated responses in human platelets. Taken collectively, the data show that the TMQ isomers interfered with the endoperoxide/thromboxane A2 receptor-mediated phospholipase C-signal cascade of inositol phospholipid hydrolysis, calcium mobilization, and protein phosphorylation leading to platelet aggregation and secretion. R(+)-TMQ acted as a pharmacologically selective and highly stereospecific [R(+)-TMQ much greater than S(-)-TMQ] antagonist of endoperoxide/thromboxane A2 receptor sites in platelets.(ABSTRACT TRUNCATED AT 400 WORDS)

Sulfonamide-containing regimens for disease caused by rifampin-resistant Mycobacterium kansasii

Fourteen wild strains and 14 relapse or treatment failure isolates of Mycobacterium kansasii were tested and found to be highly susceptible to sulfamethoxazole (SMX), with 26 of 28 isolates having minimal inhibitory concentrations (MIC) of less than or equal to 4 micrograms/ml), using a broth microdilution method. Treatment failure isolates frequently exhibited resistance to rifampin (RMP) (greater than 2 micrograms/ml), isoniazid (INH) (greater than 4 micrograms/ml), and ethambutol (EMB) (greater than 4 micrograms/ml) not seen among the wild strain isolates. Eight patients with cavitary disease caused by RMP-resistant M. kansasii were treated with SMX-containing regimens that also included high dose INH (900 mg), EMB (25 mg/kg), and an aminoglycoside (either streptomycin or amikacin). Patients were treated initially in the hospital for 4 to 10 wk. In 7 of the 8 patients, sputum cultures became negative in a mean of 10 wk (range, 7 to 14 wk). Acquired drug resistance to INH, RMP, and EMB can be demonstrated in M. kansasii, and SMX in combination with other agents chosen on the basis of MIC determinations are effective in the treatment of disease caused by RMP-resistant M. kansasii.