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Pigs with severe combined immunodeficiency (SCID) are an emerging biomedical animal model. Swine are anatomically and physiologically more similar to humans than mice, making them an invaluable tool for preclinical regenerative medicine and cancer research. One essential step in further developing this model is the immunological humanization of SCID pigs. In this work we have generated T- B- NK- SCID pigs through site directed CRISPR/Cas9 mutagenesis of IL2RG within a naturally occurring DCLRE1C (Artemis)-/- genetic background. We confirmed Art-/-IL2RG-/Y pigs lacked T, B, and NK cells in both peripheral blood and lymphoid tissues. Additionally, we and successfully performed a bone marrow transplant on one Art-/-IL2RG-/Y male SCID pig with a bone marrow from a complete swine leukocyte antigen (SLA) matched donor without conditioning to reconstitute porcine T and NK cells. Next, we performed in utero injections of cultured human CD34+ selected cord blood cells into the fetal Art-/-IL2RG-/Y SCID pigs. At birth, human CD45+ CD3ε+ cells were detected in peripheral blood of in utero injected SCID piglets. Human leukocytes were also detected within the bone marrow, spleen, liver, thymus, and mesenteric lymph nodes of these animals. Taken together, we describe critical steps forwards the development of an immunologically humanized SCID pig model.One sentence summaryWe have generated a T- B- NK- SCID pig model through site directed mutagenesis of IL2RG in a naturally occurring Artemis null background and show successful engraftment of human T and B cells in blood and lymphoid organs after in utero injection of human hematopoietic stem cells.

The5-HT2Areceptor is highly involved in aspects of cognition and executive function and seen to be affected in neurodegenerative diseases like Alzheimer’s disease and related to the disease pathology. Even though Parkinson’s disease (PD) is primarily a motor disorder, reports of impaired executive function are also steadily being associated with this disease. Not much is known about the pathophysiology behind this. The aim of this study was thereby twofold: (1) to investigate5-HT2Areceptor binding levels in Parkinson’s brains and (2) to investigate whether PD associated pathology, alpha-synuclein (AS) overexpression, could be associated with5-HT2Aalterations. Binding density for the5-HT2A-specific radioligand [3H]-MDL 100.907 was measured in membrane suspensions of frontal cortex tissue from PD patients. Protein levels of AS were further measured using western blotting. Results showed higher AS levels accompanied by increased5-HT2Areceptor binding in PD brains. In a separate study, we looked for changes in5-HT2Areceptors in the prefrontal cortex in 52-week-old transgenic mice overexpressing human AS. We performed region-specific5-HT2Areceptor binding measurements followed by gene expression analysis. The transgenic mice showed lower5-HT2Abinding in the frontal association cortex that was not accompanied by changes in gene expression levels. This study is one of the first to look at differences in serotonin receptor levels in PD and in relation to AS overexpression.

Gait disturbances and postural instability represent major sources of morbidity in Parkinson's disease (PD), and respond poorly to current treatment options. Some aspects of gait disturbances can be observed in rodent models of PD; however, knowledge regarding the stability of rodent gait patterns over time is lacking. Here we investigated the temporal constancy and reproducibility of gait patterns in neurologically intact and bilaterally 6-hydroxydopamine (6-OHDA) lesioned rats, by using an automated quantitative gait analysis method (CatWalk). The bilateral neurotoxin injections into the medial forebrain bundle resulted in an average dopamine (DA) loss of 70% in each striata, which corresponds to the DA levels observed in moderate-mid stage human PD. Rats were tested weekly during one month, and we found that in intact rats all parameters investigated remained constant over multiple tests. The 6-OHDA lesioned rats were impaired in several aspects of gait, such as stride length, swing speed, stance duration, step cycle duration, and base of support. However the stance and step cycle deficits were transient, the performance of 6-OHDA lesioned rats were indistinguishable from control rats by the last test session with regard to these parameters. Finally, we found that administration of a single dose of levodopa (L-DOPA) to the 6-OHDA lesioned rats could counteract all but one observed deficits. Based on these findings we conclude that the gait pattern of intact rats is highly reproducible, 6-OHDA lesioned rats display impairments in gait, and L-DOPA can counteract most deficits seen in this model of experimental PD.

We have examined the pattern of striatal messenger RNA expression of over 8000 genes in a rat model of levodopa (L-DOPA)-induced dyskinesia and Parkinson disease (PD). 6-Hydroxydopamine (6-OHDA)-lesioned rats were treated with L-DOPA or physiological saline for 22 days and repeatedly tested for antiakinetic response to L-DOPA and the development of abnormal involuntary movements (AIMs). In a comparison of rats that developed a dyskinetic motor response to rats that did not, we found striking differences in gene expression patterns. In rats that developed dyskinesia, GABA neurons had an increased transcriptional activity, and genes involved in Ca2+ homeostasis, in Ca2+-dependent signaling, and in structural and synaptic plasticity were upregulated. The gene expression patterns implied that the dyskinetic striatum had increased transcriptional, as well as synaptic activity, and decreased capacity for energy production. Some basic maintenance chores such as ribosome protein biosynthesis were downregulated, possibly a response to expended of ATP levels.

DeltaFosB-like proteins are particularly stable transcription factors that accumulate in the brain in response to chronic perturbations. In this study we have compared the time-course of striatal FosB/DeltaFosB-like immunoreactivity and prodynorphin mRNA expression after discontinuation of chronic cocaine treatment to intact rats and chronic L-DOPA treatment to unilaterally 6-hydroxydopamine (6-OHDA) lesioned rats. The animals were killed between 3 h and 16 days after the last drug injection. In both treatment paradigms, the drug-induced FosB/DeltaFosB immunoreactivity remained significantly elevated in the caudate putamen even at the longest withdrawal period examined. The concomitant upregulation of prodynorphin mRNA, a target of DeltaFosB, paralleled the time-course of DeltaFosB-like immunoreactivity in the 6-OHDA-lesion/L-DOPA model, but was more transient in animals treated with cocaine. These results suggest that DeltaFosB-like proteins have exceptional in vivo stability. In the dopamine-denervated striatum, these proteins may exert sustained effects on the expression of their target genes long after discontinuation of L-DOPA pharmacotherapy.

Current knowledge of the molecular changes induced by dopamine denervation and subsequent treatment with L-DOPA is based on studies performed on relatively acute and young animal models of parkinsonism. It is highly warranted to ask how well these models simulate the state of chronic denervation and sustained L-DOPA pharmacotherapy which are typical of advanced Parkinson's disease. This study investigates the effects of time postdenervation and L-dopa treatment duration on the striatal expression of opioid precursor mRNAs and FosB/DeltaFosB-related proteins. Unilaterally 6-hydroxydopamine-lesioned rats were treated with therapeutical doses of L-DOPA for one year (long-term group) or a few weeks (short-term group). Age-matched lesioned rats received injections of vehicle or bromocriptine, an antiparkinsonian compound which does not produce dyskinesia when administered de novo. The lesion-induced up-regulation of preproenkephalin mRNA expression persisted at more than one year postlesion, and was unaffected by the pharmacological treatments applied. L-DOPA, but not bromocriptine, induced high striatal levels of FosB/DeltaFosB immunoreactivity and prodynorphin mRNA, and these did not differ between short-term and long-term L-DOPA-treated rats. The present data provide the first demonstration that L-DOPA maintains high striatal levels of fosB and prodynorphin gene expression during a prolonged course of treatment, which simulates the clinical practice in Parkinson's disease more closely than the short-treatment paradigms studied thus far.

We investigate the influence of nonlinear optical Faraday rotation on polarization multistability and modulational instabilities in nonlinear resonators. The potential use of gyrotropic cavities for implementing a light polarization-controlled set–reset flip–flop element and a high-repetition-rate pulse train generator is analysed.

The interaction between electromagnetic radiation and the molecule has been analysed by an evaluation of the low-energy part of the linear response spectrum of buckminsterfullerene, . Single-particle wavefunctions, determined from local-density ground-state calculations, were used for evaluation of dipole matrix elements which, combined in a sum-over-states approach, yielded wavelength-dependent free-response microscopic linear polarizabilities. Screening of the external electromagnetic field through the induced charge distribution was determined by applying external static electric fields in separate self-consistent field calculations and by evaluation of the induced dipole moment. The polarizability calculated in the static limit was used to determine an effective screening parameter for evaluation of the dynamic response. The inclusion of screening was found to give an optical spectrum in rather good agreement with the corresponding experimentally determined spectrum of , in the gas phase or solution, by absorption measurements, EELS or photoionization techniques. Furthermore, by the use of Lorentz local field factors, we find a similar agreement for the dielectric function determined from ellipsometry and EELS measurements. In the above cases, the shapes of the spectra are essentially reproduced except for a uniform shift of about 0.5 eV to the low-energy side in the region and about 4 eV in the opposite direction in the region above 10 eV.

Using wave functions determined from ground-state local-density calculations, we have calculated the wave-dispersed free response of the optical nonlinear polarizabilityγ(3)(−3ω;ω,ω,ω), for the C60 molecule andχ(3)(−3ω;ω,ω,ω) i.e. Third-Harmonic Generation (THG) for films using a sum-over-states approach. The influence of screening was determined by applying an external static electric field in separate selfconsistent calculations to evaluate induced dipole moments which was used to determine the static linear and nonlinear polarizabilities. The polarizabilities calculated in the static limit were used to determine an effective screening parameter which was, in turn, used together with an RPA approach to calculate screened wave-dispersed, third-order nonlinear optical properties such asγ(3)(−3ω;ω,ω,ω) andχ(3)(−3ω;ω,ω,ω). Comparing evaluated polarizabilities with experimental values we found that the non-resonant free polarizability compares well in absolute magnitude with experimental results. Inclusion of screening results in a polarizability about two orders of magnitude below the experimental values.

The electronic structure of (111) surfaces of BaF 2 and CaF 2 crystals have been studied by the use of molecular cluster calculations, within the local density approximation (LDA). The surface is modelled by a 10–13-ion cluster embedded in an external potential from the surrounding crystal ions. In centrosymmetric crystals, such as BaF 2 and CaF 2 , any optical second harmonic generation (SHG) has to be due to electric quadrupole (EQ) interactions. However, in the surface region, electric dipole (ED) interactions will give SHG contributions. Using the wavefunctions obtained from the molecular cluster calculations, we have evaluated the ED part of the second-order microscopic polarizability for (111) surfaces of BaF 2 and CaF 2 . The results show strong frequency dependencies which may explain experimentally observed SHG signals from these materials. The influence of local field corrections for these systems is briefly discussed.

Background: We examined the activation pattern of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and its dependence on D1 versus D2 dopamine receptors in hemiparkinsonian rats treated with 3,4-dihydroxyphenyl-L-alanine (L-DOPA). Methods: 6-Hydroxydopamine-lesioned rats were treated acutely or chronically with L-DOPA in combination with antagonists for D1 or D2 receptors. Development of dyskinesia was monitored in animals receiving chronic drug treatment. Phosphorylation of ERK1/2, mitogen- and stress-activated protein kinase-1 (MSK-1), and the levels of FosB/Delta FosB expression were examined immunohistochemically. Results: L-DOPA treatment caused phosphorylation of ERK1/2 in the dopamine-denervated striatum after acute and chronic administration. Similar levels were observed in matrix and striosomes, and in enkephalin-positive and dynorphin-positive neurons. The severity of dyskinesia was positively correlated with phospho-ERK1/2 levels. Phosphorylation of ERK1/2 and MSK-1 was dose-dependently blocked by SCH23390, but not by raclopride. SCH23390 also inhibited the development of dyskinesia and the induction of FosB/Delta FosB. Conclusions: L-DOPA produces pronounced activation of ERK1/2 signaling in the dopamine-denervated striatum through a D1-receptor-dependent mechanism. This effect is associated with the development of dyskinesia. Phosphorylated ERK1/2 is localized to both dynorphinergic and enkephalinergic striatal neurons, suggesting a general role of ERK1/2 as a plasticity molecule during L-DOPA treatment.

3,4-Dihydroxyphenyl-l-alanine (l-DOPA)-induced dyskinesia is associated with molecular and synaptic plasticity in the basal ganglia, but the occurrence of structural remodeling through cell genesis has not been explored. In this study, rats with 6-hydroxydopamine lesions received injections of the thymidine analog 5-bromo-2′-deoxyuridine (BrdU) concomitantly withl-DOPA for 2 weeks. A large number of BrdU-positive cells were found in the striatum and its output structures (globus pallidus, entopeduncular nucleus, and substantia nigra pars reticulata) inl-DOPA-treated rats that had developed dyskinesia. The vast majority (60–80%) of the newborn cells stained positively for endothelial markers. This endothelial proliferation was associated with an upregulation of immature endothelial markers (nestin) and a downregulation of endothelial barrier antigen on blood vessel walls. In addition, dyskinetic rats exhibited a significant increase in total blood vessel length and a visible extravasation of serum albumin in the two structures in which endothelial proliferation was most pronounced (substantia nigra pars reticulata and entopeduncular nucleus). The present study provides the first evidence of angiogenesis and blood–brain barrier dysfunction in an experimental model ofl-DOPA-induced dyskinesia. These microvascular changes are likely to affect the kinetics ofl-DOPA entry into the brain, favoring the occurrence of motor complications.

Single particle wavefunctions determined from a local density calculation of the C60 and KC60 ground states are used for evaluation of microscopic wavelength dependent polarizabilities and absorption spectrum with a sum-over-states approach. Coulomb screening of the external electromagnetic field through the induced charge distribution is included by a simple RPA type correction of the free response. The evaluated spectrum is found to be in rather good agreement with the experimentally determined absorption spectrum of C60 in solution.

Using local density ground state wavefunctions and local field factors determined from the linear case, we calculate the dispersion of the lowest order nonlinear susceptibilityx (3)(−3θ; θ, θ, θ), using a sum-over-states approach. The largest contributions to the corresponding nonlinear polarizability γ(3) in the low energy range (≤8eV) are identified. We compare theoretical values with results from Third Harmonic Generation (THG) experiments on C60 deposited as a thin film. The dispersion could be rather well described by a screenedx (3).

Current knowledge of the molecular changes induced by dopamine denervation and subsequent treatment with L-DOPA is based on studies performed on relatively acute and young animal models of parkinsonism. It is highly warranted to ask how well these models simulate the state of chronic denervation and sustained L-DOPA pharmacotherapy which are typical of advanced Parkinson's disease. This study investigates the effects of time postdenervation and L-dopa treatment duration on the striatal expression of opioid precursor mRNAs and FosB/DeltaFosB-related proteins. Unilaterally 6-hydroxydopamine-lesioned rats were treated with therapeutical doses of L-DOPA for one year (long-term group) or a few weeks (short-term group). Age-matched lesioned rats received injections of vehicle or bromocriptine, an antiparkinsonian compound which does not produce dyskinesia when administered de novo. The lesion-induced up-regulation of preproenkephalin mRNA expression persisted at more than one year postlesion, and was unaffected by the pharmacological treatments applied. L-DOPA, but not bromocriptine, induced high striatal levels of FosB/DeltaFosB immunoreactivity and prodynorphin mRNA, and these did not differ between short-term and long-term L-DOPA-treated rats. The present data provide the first demonstration that L-DOPA maintains high striatal levels of fosB and prodynorphin gene expression during a prolonged course of treatment, which simulates the clinical practice in Parkinson's disease more closely than the short-treatment paradigms studied thus far.

Contact lenses are frequently fitted so that one eye is focused for distance and the other for near (monovision) in order to reduce the dependence of presbyopic patients on bifocal spectacle correction.We surveyed Diplomates in the Cornea and Contact Lens section of the American Academy of Optometry (N = 179) regarding their estimates of success with monovision fitting and factors influencing their perception of success. Results were statistically analyzed to determine the fitting philosophies of responders estimating that they achieve high success rates (HSRs) and low success rates (LSRs), respectively.Completed surveys were returned by 98 Diplomates (54.8%), who estimated an overall success rate of approximately 71.7% with monovision; 50.5% "totally successful" (wear monovision correction full-time without problems or need for additional correction) and 21.2% "successful" (wear monovision full-time, but experience some symptoms of blur or other discomfort, may wear over-correction at times for driving or detailed near work). Sighting dominance was the most frequently used method to determine the distant eye, followed by the plus-lens test. The HSR group tended to be more likely to take occupational factors into account when deciding which eye to use for the distance lens, and they used more flexibility in determining the near-add power. The LSR group discontinued monovision sooner than the HSR group, who continued treatment for longer than 4 weeks during the adaptation period much more often for all add ranges.Practitioners who regard monovision treatment as very successful have somewhat different fitting philosophies than those who regard monovision as unsuccessful. Implementation of highly successful practitioners' fitting techniques may increase success with monovision contact lens fitting.

We propose nonlinear Faraday rotation as a mechanism for achieving stable polarization mode locking of a soliton laser. We analyze by perturbation theory and beam-propagation simulations the interplay between bandwidth-limited gain, gain dichroism, and linear and nonlinear Faraday rotation.

Molecular cluster calculations within the Local Density Approximation have been performed to analyze the electronic structure of stoichiometric and different non-stoichiometric (111) surfaces of CaF2. The effect of the surrounding crystal ions, i.e. the long range electrostatic potential, have been included by a Fourier summation. Calculations for clusters representing the bulk and stoichiometric surfaces give similar results while calculations for non-stoichiometric surfaces show the existence of occupied surface states in the upper half of the bandgap. Existence of these types of occupied surface states are supported by experimental EELS studies on CaF2 as well as by observation of laser induced emission of ions and electrons from surfaces of BaF2.

We show that, owing to the generation of soliton bound states, the interaction between optical fiber solitons can be fully suppressed by means of narrow-band Butterworth-type filters with flat-topped transmission characteristics.

Polarization and azimuthal dependencies of optical second-harmonic generation at the surface of cubic ionic crystals have been measured on polished surfaces of BaF2 (111) and (100), CaF2 (111) and NaCl (111), using a fundamental wavelength of 532 nm. The results are interpreted in terms of available theory, which shows that for transparent cubic media only the dipolar surface contribution depends on the crystal orientation. For BaF2 (111) and NaCl (111) the crystallineC3vgeometry could be identified but not for CaF2 (111). Although the nature of the electronic surface structure giving rise to a dipolar polarizability remains undetermined, the experimental result suggests that it may be due to impurity or defect states in the band gap at the surface.

The subject of this contribution is multiphoton interaction of laser light in the blue and green spectral ranges with cleaved and polished (111) surfaces of BaF2 in ultrahigh vacuum and air. We claim that photoemission and laser-induced non-thermal desorption of positive ions are triggered by nonlinear absorption of some order between two and five. Photoemission and ion desorption yields are strongly wavelength dependent and display conspicuous resonance structures, with striking similarities between electron and ion yield spectra. Cluster calculations are performed in an attempt to understand the origin of these resonances. They predict the existence of occupied surface states near the middle of the bandgap together with a high density of resonances in the upper half of the bandgap. Measurements of the surface second harmonic generation in air showed a similar wavelength dependence as the electron yield in vacuum. The transition from pure second harmonic generation to plasma discharge was studied and evidence is presented that the discharge is ignited by resonant multiphoton absorption in adsorbed gas molecules.

The subject of this presentation is to show how molecular cluster calculations can lead to a deeper understanding of laser induced processes at surfaces of ionic crystals. Molecular cluster calculations were performed for bulk BaF2 and for different clusters modelling the (111) surface of BaF2. The effect of the surrounding crystal ions have been included by an embedding crystal potential. Calculations for a stoichiometric surface give an electronic structure similar to the bulk, while calculations for a local non-stoichiometric surface show the existence of occupied surface states in the upper half of the bandgap, followed by unoccupied states extending above the ionization limit. These calculations give a qualitative understanding of the experimentally observed resonantly enhanced multiphoton processes of electron and ion emission from the (111) surface of BaF2.

A full-length human c-myb cDNA clone has been isolated from a CCRF-CEM leukemia cell cDNA library. The plasmid vector contains simian virus 40-derived promotor, splice, and polyadenylation sequences as well as a transcription unit for a dihydrofolate reductase cDNA. We have introduced this construct into Friend erythroleukemia (F-MEL) cells and have isolated a number of clones which contain intact and transcriptionally active human c-myb sequences. F-MEL clones expressing the highest levels of the human c-myb mRNA differentiate poorly in response to dimethyl sulfoxide. Two clones which initially expressed low levels of human c-myb transcripts and which differentiated normally were subsequently inhibited in their ability to differentiate when grown in successively higher concentrations of methotrexate, due to amplification and enhanced expression of plasmid sequences. The inhibitory effect on F-MEL differentiation appeared to be independent of the early decline in c-myc transcripts which were normally regulated in all cases examined. Our results indicate that constitutive expression of a nontruncated human c-myb cDNA can exert profound effects on erythroid differentiation and argue for a causal role of c-myb in the F-MEL differentiation process.

The interaction of laser radiation and surfaces of optically transparent ionic materials is an important problem in surface science as well as in applied optics. For the latter, the question of how optical damage occurs, is of fundamental interest. Since the bandgap of ionic crystals is of the order of 10 eV, for visible light only multiphoton absorption can result in energy deposition into the surface. Structural defects, impurities, and adsorbates can generate surface states which are located somewhere in the bandgap, and can resonantly enhance multiphoton photoemission. This, in turn, can lead to desorption of ions and neutrals at comparatively low intensities. In this contribution we present results of photoemission and desorption studies carried out in ultra-high vacuum with cleaved (111) surfaces of BaF2, at laser intensities in the MW/cm2 range.

The transforming genes of retroviruses (v-onc) are derived from normal cellular genes referred to as proto-oncogenes. These cellular genes have the capacity for conversion to oncogenes (c-onc) that are capable of inducing or maintaining the transformed state when they are overly expressed or altered by mutation or rearrangement. To study the possible involvement of these genes in human leukemia, we have analyzed their expression in a variety of fresh samples. We found that a number of oncogenes are expressed in different leukemic types and that although the transcript size did not vary for each gene, the copy number did. The myc gene (2.4 kb transcript) and the rasHa gene (1.5 kb transcript) were universally expressed. But in contrast to rasHa, the myc signal intensity varied. Myb (4.5 kb transcript) was expressed in all samples except B cell diseases. We detected low levels of abl expression (multiple mRNA species) in all leukemic types analyzed. Sis gene (4.2 kb transcript) expression was restricted to one patient sample with chronic myelogenous leukemia in blast transformation.

We have investigated the wavelength, polarization, and intensity dependence of the electron and ion emission from the (111) surface of BaF2 under irradiation with pulsed tunable laser light in the green and blue spectral ranges. We also carried out cluster calculations to obtain a prediction for the electronic surface structure of BaF2 (111). Based on these results, a qualitative model for the desorption of positive ions from this surface is proposed.

Recent studies in this laboratory have been directed at investigating the cellular and subcellular metabolism of RNA in leukemic cells which have been characterized with respect to their degree and type of sensitivity/resistance to specific chemotherapeutic agents. In the present report, electrophoretic patterns on several types of SDS-polyacrylamide gels are presented using total cellular RNA preparations from a subline of L1210 mouse leukemia found to be resistant to cytosine arabinoside (L1210/Ara-C). These studies have been facilitated by using a computerized-spectrophotometric system for quantitative and qualitative comparisons of these profiles. The results suggest that patterns of RNA metabolism may be a useful biochemical test in leukemia.

To understand the onset of laser-induced damage on surfaces of transparent ionic materials, we have studied the effect of tunable laser light on cleaved BaF2 (111) surfaces in ultrahigh vacuum conditions, using intensities well below the macroscopic damage threshold. Between 415 and 435 nm strong emission bands were observed for the positive ions Ba+, Ba2+, (BaF)+, F+, and for neutral fluorine. For power densities smaller than 5 × 107W/cm2 the emission yield varies from site to site. All active spots bleach out after a few thousand laser shots. We also find evidence that the desorption yield is sensitive to individual layers. From measurements of the photoelectron yield for various wavelengths a two-photon process was identified, indicating the existence of an occupied surface state with binding energy of about −4.3eV. Cluster calculations support this observation and predict in addition several excitonic states in the upper half of the band gap. We suggest that the wavelength-dependent desorption is triggered by a resonantly enhanced two-photon ionization from this occupied surface state leading to a positive charge-up of the surface which, in turn, results in the emission of positive ions.

In this contribution we present experimental results on the angular, polarization, and wavelength dependence of second harmonic generation (SHG) on polished BaF2 (111) surfaces in air. These measurements are part of a program to investigate the electronic surface structure of alkaline-earth fluoride crystals under various conditions. The first results on optical SHG on surfaces of BaF2 were reported as early as 1968 by Wang and Duminski /1/. Meanwhile, guided by the pioneering work of Shen and collaborators /2/, the technique has matured into a powerful analytical tool for the investigation of surface structures, and we find it worthwhile to apply it further to surfaces of transparent ionic materials.

Sequential stimulation and washout procedures were employed to examine the kinetics and reversibility of pharmacologically manipulated second messenger signals mediating phenotypic changes and proliferative activation of resting human T lymphocytes. Phorbol dibutyrate (PDBu) was used to stimulate protein kinase C (Ca2+/phospholipid-dependent enzyme) while ionomycin was used to manipulate intracellular Ca2+ levels. Stimulation by PDBu alone induced phosphorylation of several endogenous substrates and altered expression of phenotypic markers, downregulating expression of CD4 and CD3 while increasing expression of CD2 and the interleukin 2 (IL-2) receptor. Stimulation with ionomycin alone caused an increase in intracellular Ca2+ levels but did not induce proliferation or cause major changes in the expression of phenotypic markers (CD2, CD3, CD4, CD8, IL-2, and transferrin receptors). Analysis of endogenous PDBu stimulated phosphosubstrates indicated that some substrates (pp92, pp82, pp55) underwent dephosphorylation, returning to base-line levels following PDBu removal while others (pp61, pp65) showed only partial dephosphorylation, while one (pp28) remained phosphorylated. Washing ionomycin-stimulated cells resulted in an approximately 75% reduction of intracellular Ca2+. Ionomycin exposure did not alter the affinity (KD = 22.3 +/- 7.4 nM) or number of receptors (53,497 +/- 8,291 receptors/cell) for [3H]PDBu. These data suggest that signals induced by PDBu or ionomycin are reversible following removal of the stimulating agents with respect to proliferative activation of T lymphocytes. Furthermore, a transcriptional mechanism regulating the production of IL-2 mRNA requires simultaneous activation of protein kinase C and elevation of intracellular Ca2+.

Transfection is a technique for inducing transformation of normal fibroblasts (NIH 3T3) with DNA (oncogenes) from human tumors. Our goal was to determine if these transformed cells expressed antigens associated with malignancy. NIH 3T3 cells were transfected with DNA fragments from a human acute lymphocytic leukemia (ALL 1-69), and transformed colonies were selected for growth in soft agar. Transfected cells containing human DNA sequences demonstrated by Southern blot analysis were used to immunize Balb/C mice. Monoclonal antibodies were produced and screened for binding to the parental leukemia (ALL 1-69), transfectant (17(2], and 3T3 cells in an enzyme-linked assay. A monoclonal antibody (IgM kappa) designated 17-9H3 bound to ALL 1-69 and secondary transfectant 17(2) but not to NIH 3T3 plasma membranes. Immunoperoxidase staining confirmed this binding pattern and demonstrated that the antigen was expressed on the cell surface. Expression of the antigen by transfectants directly correlated with the presence of a single 6.1 kilobase human DNA sequence. The antibody binding site of the antigen was inactivated by trypsin, glucosidase, and hyaluronidase. Binding of the 17-9H3 antibody was selective for acute lymphocytic leukemias (5/8) and osteogenic sarcomas (33/36), although other tumor types did demonstrate significant binding by immunoperoxidase staining. The majority of normal tissues did not bind 17-9H3 with the exception of some metabolically active cells (renal tubular epithelium, secretory epithelial cells, and cardiac smooth muscle), germ cells, Leydig cells of the testes, and some lymphoid cells. Monoclonal antibodies to oncogene-associated antigens may be potentially useful for cancer diagnosis and therapy and as probes for oncogene isolation.

This paper is addressed to the question of surface states on the (111)-surface of BaF2, which can serve as a model for other divalent ionic crystals. The goal is to prove that surface states, which are energetically located in the middle and upper half of the bandgap, play a decisive role in the desorption process. They can either absorb single photons which results in local heating and thermal desorption or, more of interest in this context, they can resonantly enhance multiphoton absorption.

Viral transforming (v-onc) genes are derived from cellular (c-onc) genes that are highly conserved among vertebrates. Comparative studies of v-onc and c-onc genes have shed some light on the mechanism leading to formation of the transforming viruses. A specific example of the sis gene is presented here for illustration. Studies on the expression of six c-onc genes in human cells revealed at least three categories of onc genes: (a) those that are universally expressed and probably are important in basic cellular functions, (b) those that are not detectably expressed in the cells examined and may have very transient expression in development, and (c) those that are only expressed in specific cell types and may be important in tissue differentiation. Our studies do not show conclusively a role of these onc genes in human neoplasias.

Laser-induced emission of electrons and positive ions as well as optical second harmonic generation (SHG) at the (111) surface of BaF2 yield insight in both the electronic surface structure and the fundamentals of laser damage in optical materials.

A recent case of Lipiodol Ultrafluid embolism to the brain is reported. Pathogenetic concepts involving right-to-left shunts, and lympho-venous shunts with pulmonary capillary overloading are reviewed. In addition, it is suggested that a local disturbance in cerebral circulation due to a cava superior syndrome may contribute to the severe cerebral symptoms.

Measurements of laser‐induced desorption under ultrahigh vacuum conditions and second harmonic generation on surfaces in air provide evidence for surface electronic states in the band gap of ionic materials. When irradiating BaF2(111) with green laser light narrow resonances of electron and ion emission yields indicate resonance enhancement of multiphoton absorption. Using fundamental light of 532 nm, second harmonic generation behaves different for BaF2(111) and NaCl(111) on one side and CaF2(111) on the other. In the first two cases, its azimuthal dependence proves that the second harmonic yield originates from local dipole interaction at the surface. In contrast, the CaF2(111) surface appears to be more inert and the second harmonic signal originates predominantly from quadrupole interaction in the bulk.

Wavelength and intensity dependencies of laser-induced electron and positive ion emission from a BaF2 (111) surface were studied in the MW/cm2 intensity range, well below the damage threshold. In the range 500 to 560 nm we find similar shapes for the spectral emission yields of electrons and ions. Electrons are emitted by two- and five-photon absorption below and above 1.5 MW/cm2, respectively. In contrast, ion desorption involves a ten-photon process, suggesting that two holes in the valence band are required. The interpretation of the data is supported by molecular cluster calculations. In the blue spectral range at higher intensities (∼50 MW/cm2) we observe rapid bleaching of the irradiated spots and evidence for layer-by-layer ablation.

The progress achieved by Planetary Sciences Incorporated from January through March, 1963, on the preliminary analysis and interpretation of the digitized strong-motion seismograms is described. Research and analysis for seven digital computer programs have been done. Six of the programs have been flowcharted, coded, and debugged on the IBM 1620. The seventh (PSI015) was processed on the IBM 7090 and CalComp plotter.

Subject of this paper is the interaction between laser radiation and surfaces of optically transparent ionic crystals at low‐power densities of the order of 106–107 W/cm2. By studying the wavelength and intensity dependencies of electron and ion‐emission yields, it is shown that surface states play a decisive role for photon absorption at surfaces of divalent ionic crystals. They resonantly enhance multiphoton processes which leads to a strong‐wavelength dependence of both photoemission and ion desorption. Cluster calculations confirm the existence of occupied surface states in the middle of the band gap and of unoccupied states in its upper half as well as above the ionization limit. The dependence on laser intensity reveals both two‐ and five‐photon processes for photoemission, and ten‐photon processes for the desorption of positive ions. The latter is interpreted as the creation of two holes, each by five‐photon absorption, with subsequent Coulomb repulsion of a positive ion.