Hosing of a Long Relativistic Particle Bunch in Plasma

Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven by a short, misaligned preceding bunch. Hosing develops in the plane of misalignment, self-modulation in the perpendicular plane, at frequencies close to the plasma electron frequency, and are reproducible. Development of hosing depends on misalignment direction, its growth on misalignment extent and on proton bunch charge. Results have the main characteristics of a theoretical model, are relevant to other plasma-based accelerators and represent the first characterization of hosing.

How can patient registries facilitate guideline-based healthcare? A retrospective analysis of the CEDATA-GPGE registry for pediatric inflammatory bowel disease

BACKGROUND

Early diagnosis is mandatory for the medical care of children and adolescents with pediatric-onset inflammatory bowel disease (PIBD). International guidelines ('Porto criteria') of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition recommend medical diagnostic procedures in PIBD. Since 2004, German and Austrian pediatric gastroenterologists document diagnostic and treatment data in the patient registry CEDATA-GPGE on a voluntary basis. The aim of this retrospective study was to analyze whether the registry CEDATA-GPGE reflects the Porto criteria and to what extent diagnostic measures of PIBD according to the Porto criteria are documented.

METHODS

Data of CEDATA-GPGE were analyzed for the period January 2014 to December 2018. Variables representing the Porto criteria for initial diagnostic were identified and categorized. The average of the number of measures documented in each category was calculated for the diagnoses CD, UC, and IBD-U. Differences between the diagnoses were tested by Chi-square test. Data on possible differences between data documented in the registry and diagnostic procedures that were actually performed were obtained via a sample survey.

RESULTS

There were 547 patients included in the analysis. The median age of patients with incident CD (n = 289) was 13.6 years (IQR: 11.2-15.2), of patients with UC (n = 212) 13.1 years (IQR: 10.4-14.8) and of patients with IBD-U (n = 46) 12.2 years (IQR: 8.6-14.7). The variables identified in the registry fully reflect the recommendations by the Porto criteria. Only the disease activity indices PUCAI and PCDAI were not directly provided by participants but calculated from obtained data. The category 'Case history' were documented for the largest part (78.0%), the category 'Imaging of the small bowel' were documented least frequently (39.1%). In patients with CD, the categories 'Imaging of the small bowel' (χ² = 20.7, Cramer-V = 0.2, p < 0.001) and 'Puberty stage' (χ² = 9.8, Cramer-V = 0.1, p < 0.05) were documented more often than in patients with UC and IBD-U.

CONCLUSION

The registry fully reproduces the guideline's recommendations for the initial diagnosis of PIBD. The proportion of documented diagnostic examinations varied within the diagnostic categories and between the diagnoses. Despite technological innovations, time and personnel capacities at participating centers and study center are necessary to ensure reliable data entry and to enable researchers to derive important insights into guideline-based care.

Controlled Growth of the Self-Modulation of a Relativistic Proton Bunch in Plasma

A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefields with the charge of the electron bunch and the growth rate of SM with the charge of the proton bunch. Seeding leads to larger growth of the wakefields than in the instability case.

Transition between Instability and Seeded Self-Modulation of a Relativistic Particle Bunch in Plasma

We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of a long proton bunch in plasma. We show experimentally that, with sufficient initial amplitude [≥(4.1±0.4)  MV/m], the phase of the modulation along the bunch is reproducible from event to event, with 3%-7% (of 2π) rms variations all along the bunch. The phase is not reproducible for lower initial amplitudes. We observe the transition between these two regimes. Phase reproducibility is essential for deterministic external injection of particles to be accelerated.

RRAM-based synapse devices for neuromorphic systems

Hardware artificial neural network (ANN) systems with high density synapse array devices can perform massive parallel computing for pattern recognition with low power consumption. To implement a neuromorphic system with on-chip training capability, we need to develop an ideal synapse device with various device requirements, such as scalability, MLC characteristics, low power operation, data retention, and symmetric/linear conductance changes under potentiation/depression modes. Although various devices have been proposed for synapse applications, they have limitations for application in neuromorphic systems. In this paper, we will cover various RRAM synapse devices, such as filamentary switching RRAM (HfOx, TaOx, Cu-CBRAM) and analog RRAM devices, based on interface resistive switching (Pr0.7Ca0.3MnOx and TiOx) and ferroelectric polarization (HfZrOx). By optimizing potentiation/depression conditions, we could improve the conductance linearity and MLC characteristics of filamentary synapse devices. Interface RRAM has better MLC characteristics with limited retention and conductance linearity. By controlling the reactivity of metal electrodes and the oxygen concentration in oxides, we can modulate the synapse characteristics. Metal-Ferroelectric-Insulator-Semiconductor (MFIS) FET devices exhibit good retention characteristics and analog memory characteristics due to polarization. Based on various synapse device characteristics, we have estimated the pattern recognition accuracy of MNIST handwritten digits and CIFAR-10 datasets. We have confirmed that synapse device characteristics directly affect the pattern recognition accuracy of ANNs. In order to simultaneously satisfy all the requirements of synapse devices, it is necessary to develop new technology capable of controlling the movement of oxygen vacancies and metal ions at the atomic scale. Considering the limited synapse characteristics of current 2-terminal RRAM devices, hardware ANNs capable of only off-chip training can be constructed by optimizing the current RRAM devices by limiting the bit number. A 3-terminal synapse device or a device based on a new operation principle should be developed as an alternative for on-chip training applications.

Computational Modeling of Venous Sinus Stenosis in Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

Idiopathic intracranial hypertension has been associated with dural venous sinus stenosis in some patients, but the hemodynamic environment of the dural venous sinuses has not been quantitatively described. Here, we present the first such computational fluid dynamics model by using patient-specific blood pressure measurements.

MATERIALS AND METHODS

Six patients with idiopathic intracranial hypertension and at least 1 stenosis or atresia at the transverse/sigmoid sinus junction underwent MR venography followed by cerebral venography and manometry throughout the dural venous sinuses. Patient-specific computational fluid dynamics models were created by using MR venography anatomy, with venous pressure measurements as boundary conditions. Blood flow and wall shear stress were calculated for each patient.

RESULTS

Computational models of the dural venous sinuses were successfully reconstructed in all 6 patients with patient-specific boundary conditions. Three patients demonstrated a pathologic pressure gradient (≥8 mm Hg) across 4 dural venous sinus stenoses. Small sample size precludes statistical comparisons, but average overall flow throughout the dural venous sinuses of patients with pathologic pressure gradients was higher than in those without them (1041.00 ± 506.52 mL/min versus 358.00 ± 190.95 mL/min). Wall shear stress was also higher across stenoses in patients with pathologic pressure gradients (37.66 ± 48.39 Pa versus 7.02 ± 13.60 Pa).

CONCLUSIONS

The hemodynamic environment of the dural venous sinuses can be computationally modeled by using patient-specific anatomy and physiologic measurements in patients with idiopathic intracranial hypertension. There was substantially higher blood flow and wall shear stress in patients with pathologic pressure gradients.

Posterior Inferior Cerebellar Artery Patency after Flow-Diverting Stent Treatment

BACKGROUND AND PURPOSE

The rate of PICA occlusion after flow-diverting stent placement for vertebral and vertebrobasilar artery aneurysms is not known. The purpose of this study is to determine the medium-term rate of PICA patency and risk factors for occlusion after such aneurysm treatment.

MATERIALS AND METHODS

Patients were identified who had vertebral or vertebrobasilar artery aneurysms and who were treated by placing a flow-diverting stent across the PICA ostium. Demographic and procedural factors associated with stent placement were recorded. Patency of the PICA was evaluated immediately after stent placement and on follow-up angiography.

RESULTS

Thirteen patients with vertebral or vertebrobasilar artery aneurysms were treated in the study period, of whom 4 presented with subarachnoid hemorrhage. The average number of devices that spanned the PICA ostium was 1.77 (range, 1-3), with no immediate PICA occlusions. There were no postoperative strokes in the treated PICA territory, although there was 1 contralateral PICA-territory stroke of unclear etiology without clinical sequelae. In 11 patients with follow-up angiography at a mean of 10.6 months (range, 0.67-27.9 months), the PICA patency rate remained 100%.

CONCLUSIONS

Flow-diverting stent placement across the PICA ostium in the treatment of vertebral and vertebrobasilar artery aneurysms may not result in immediate or midterm PICA occlusion.

Readout of superconducting flux qubit state with a Cooper pair box

We study a readout scheme of a superconducting flux qubit state with a Cooper pair box as a transmon. The qubit states consist of the superpositions of two degenerate states where the charge and phase degrees of freedom are entangled. Owing to the robustness of the transmon against external fluctuations, our readout scheme enables the quantum non-demolition and single-shot measurement of flux qubit states. The qubit state readout can be performed by using the nonlinear Josephson amplifiers after a π/2 rotation driven by an ac electric field.

De novo appearance of primitive neuroectodermal tumor in a patient with systemic lupus erythematosus and moyamoya disease

Primitive neuroectodermal tumor is a rare brain tumor composed of undifferentiated or poorly differentiated neuroepithelial cells with a high malignant potential that usually occurs in children, and which is only occasionally encountered in adults. A 19-year-old female with systemic lupus erythematosus presented with right hemiparesis and a headache of 10 days duration. Brain magnetic resonance imaging showed a large solid mass with necrotic portions in the left frontoparietal lobe. Primitive neuroectodermal tumor was confirmed by a neuronavigator-guided brain biopsy. This is the first case report of primitive neuroectodermal tumor associated with systemic lupus erythematosus and moyamoya disease. This case demonstrates that brain tumors, such as primitive neuroectodermal tumor, should be included in the differential diagnosis of neurological manifestations in children and adolescent patients with systemic lupus erythematosus.

Change in the interfacial reaction of Hf-silicate film as a function of thickness and stoichiometry

Medium energy ion scattering and high-resolution transmission electron microscopy are used to investigate the depth of the interfacial reaction of Hf-silicate film. The interfacial reaction is critically affected by the film thickness and the mole fraction of HfO(2) in silicate film. The interfacial compressive strain generated at the surface of the Si substrate is dependent on the film thickness during the postannealing process in film with a thickness of approximately 4 nm. Finally, the phase separation phenomenon demonstrates critically different behaviors at different film thicknesses and stoichiometries because the diffusion of Si from interface to surface is dependent on these factors. Moreover, the oxidation by oxygen impurity in the inert ambient causes SiO(2) top formation.

Highly birefringent terahertz polarization maintaining plastic photonic crystal fibers

Guided-wave propagation of sub-ps terahertz (THz) pulses in a highly birefringent plastic photonic crystal fiber was studied by using a THz time domain spectroscopy technique. The plastic photonic crystal fiber was fabricated by using high density polyethylene tubes and solid filaments. The fabricated THz plastic photonic crystal fibers exhibit an extremely large birefringence of ~ 2.1 x 10(-2), which is almost one order of magnitude larger than that of previously reported photonic crystal fibers.

Development of Eddy Current Sensor systems in artificial heart for noncontact gap sensing

The axial flow pump has been developed in Korea Artificial Organ Center. It consists of an impeller, a motor and a magnetic bearing. The magnetic bearing fully levitates the impeller not to contact with other parts of pump. However, in order to control the gap between the impeller and other parts, continuous gap sensing is necessary. The conventional gap sensors are relatively large to implant in artificial heart. Thus, the compact eddy current sensor system proper for artificial heart was developed and the performances were evaluated. It showed good results and has small size. However, the dependency of the sensor upon temperature and target material was shown also. Moreover, the output of sensor had nonlinear responses. These must be calibrated in further study.

Clinical Utility of Multislice Computed Tomographic Angiography for Detection of Cerebral Vasospasm in Acute Subarachnoid Hemorrhage

Digital subtraction angiography (DSA) has been used as the standard method for detecting cerebral vasospasm after subarachnoid hemorrhage (SAH). Multislice computed tomographic angiography (CTA) is a relatively recent method used for evaluating the vasculature of the intracranial arteries. The purpose of this study was to compare multislice CTA and DSA for the detection and quantification of cerebral vasospasm after SAH, and to analyze the usefulness of multislice CTA. Eight patients with SAH underwent initial CTA with DSA within 72 hours after the onset of symptoms and follow-up multislice CTA and DSA 8 to 48 days after SAH. Five arterial locations were established in the A1 and A2 segments of the anterior cerebral artery, the M1 and M2 segments of the middle cerebral artery and the posterior cerebral artery (PCA) on both multislice CTA and DSA images. Vasospasm was classified as none, mild (up to 30% reduction in luminal diameter), moderate (31-60% reduction), and marked (at least 60% reduction) using the scale of Schneck and Kricheff. The multislice CT system used the following parameters: 1.25 mm collimation and 3.75 pitch with a 4-channel system. The degree of vasospasm revealed by the multislice CTA was significantly correlated with the degree of vasospasm revealed by DSA. In general, most discrepancies between CTA and DSA were in the detection of mild and moderate vasospasm. We found that the consistency between multislice CTA and DSA was greater for mild (100%, n=3) or moderate (100%, n=3) vasospasm than none (n=1) or marked vasospasm (n=1). However, it was unclear whether multislice CTA was more specific for a proximal location (A1, M1, PCA) or distal location (A2, M2) for evaluation of cerebral arteries. Multislice CTA can detect angiographic vasospasm after SAH with an accuracy similar to that of DSA. Multislice CTA is highly sensitive, specific and accurate in detecting mild and moderate cerebral vasospasm. It is less accurate for detecting no vasospasm and marked vasospasm. Therefore, the authors propose that multislice CTA be considered as a useful tool for the detection and management of intracranial vasospasm after SAH.

In situ regeneration of rice (Oryza sativa L.) callus immobilized in polyurethane foam

An in situ regeneration system for rice calli comprised of a callus growth stage and two regeneration stages was developed. After the first stage of regeneration, the medium is changed and the calli are immobilized in polyurethane foam supports, in each of which 3-5 regenerated plantlets develop from the immobilized calli during the second stage. While no significant change in callus size was observed during the first stage of regeneration, in the second stage callus enlargement and shoot regeneration predominated. In the light of these findings, calli were immobilized in the second stage after medium exchange. The use of 10-mm support cubes with an average pore size of 3.6 mm resulted in the most efficient immobilization and in situ regeneration. Medium exchange after 15 d gave the largest number of support cubes with shoots. When rice calli were cultivated in support cubes placed in 60 ml second-stage medium in a 500-ml flask, the immobilization ratio was 83%, and 82% of the support cubes contained 3-5 regenerated plantlets after 25 d. The shoot lengths of the regenerated plantlets obtained from the in situ regeneration culture were longer than those from a suspension culture. When support cubes with 3-5 regenerated plantlets were transferred from the flask to 1 4 MS solid medium supplemented with 10 g/l sorbitol and 5 g/l sucrose, the regenerated plantlets developed quickly into plants with a length above 10 cm after 10 d.

Theory of microwave parametric down-conversion and squeezing using circuit QED

We study theoretically the parametric down-conversion and squeezing of microwaves using cavity quantum electrodynamics of a superconducting Cooper-pair box (CPB) qubit located inside a transmission line resonator. The nonlinear susceptibility chi2 describing three-wave mixing can be tuned by dc gate voltage applied to the CPB and vanishes by symmetry at the charge degeneracy point. We show that the coherent coupling of different cavity modes through the qubit can generate a squeezed state. Based on parameters realized in recent successful circuit QED experiments, squeezing of 95% approximately 13 dB below the vacuum noise level should be readily achievable.

Neuronavigation-Guided Endoscopic Surgery for Pineal Tumors with Hydrocephalus

We have applied the neuronavigation system to endoscopic biopsy and third ventriculostomy in the management of patients with a pineal tumor with hydrocephalus. With the guidance of neuronavigation, the two optimal sites of burr hole and trajectories were planned preoperatively, and the advancing endoscopic device was monitored in real time during the procedure. In our five patients, the diameters of the tumors were 2-3 cm, and the mean systemic accuracy of registration with neuronavigation was 1.2 mm. The biopsy and third ventriculostomy were performed successfully via the respective optimal burr hole and the trajectory determined using preoperative neuronavigation. There were no procedure-related complications, and none of the patients needed another procedure for CSF diversion during the follow-up periods. We present our technique which includes the application of the neuronavigation system to the biopsy and third ventriculostomy in pineal tumor with associated hydrocephalus. This technique can be performed using a simple rigid endoscope via the determined optimal entries and trajectories. The optimal preoperative planning and the intraoperative guidance by neuronavigation are thought to be able to give more chances to minimize the brain injury related to movements or deviation of endoscopic device.

Enhanced regeneration of rice (Oryza sativa L.) embryogenic callus by light irradiation in growth phase

The effect of light irradiation on the growth and regeneration of embryogenic rice calli was investigated. Rice calli grew slightly better in the light than in the dark during the growth stage. When calli subcultured under light irradiation were transferred into a liquid regeneration culture system, the number of plantlets with shoots regenerated from calli subcultured in the light was higher than in the case of those subcultured in the dark, whereas there was no obvious difference between the light and dark subcultures when a solid medium was used for the regeneration. The number of regenerated plantlets increased with increasing light intensity up to 2000 lx, but remained the same when the light intensity was raised further. The maximum number of regenerated plantlets was obtained under a photoperiod of 16 h/d. About 8800 plantlets per liter-medium were regenerated from light-cultured calli, which is 1.5 times more than the number regenerated from calli grown in the conventional dark culture.

Phosphatidylinositol 3-kinase stimulates muscle differentiation by activating p38 mitogen-activated protein kinase

The activation of both phosphatidylinositol 3-kinase (PI3-kinase) and p38 mitogen-activated protein kinase (p38 MAPK) is required for muscle differentiation. However, it is not known whether the signals from these two kinases interact during this process. In this work, we have investigated this using H9c2 cardiac myoblasts. The p38 MAPK-specific inhibitor SB203580 blocked muscle differentiation and suppressed the expression of myogenin and myosin heavy chain in a concentration-dependent manner. Consistent with this, expression of a wild-type p38 MAPK (Ha-p38) or a constitutively active MAPK kinase 6 (MKK6(glu)) promoted the rate of differentiation into multinucleated myotubes. LY294002, a PI3-kinase inhibitor, suppressed in a dose-dependent manner not only muscle differentiation but also activation of p38 MAPK. In addition, expression of a constitutively active form of PI3-kinase (p110*) enhanced myotube formation and p38 MAPK activation, while expression of a dominant negative form of PI3-kinase (Deltap85) attenuated these responses. Furthermore, SB203580 suppressed differentiation of H9c2 cells expressing p110*. Interestingly, LY294002 also suppressed differentiation of H9c2 cells expressing Ha-p38 or MKK6(glu). However, SB203580 did not affect PI3-kinase activity, suggesting that PI3-kinase myogenic signaling to p38 MAPK is unidirectional. Taken together, we concluded that PI3-kinase activates p38 MAPK, which in turn stimulates muscle differentiation, but that p38 MAPK does not substitute for PI3-kinase in this process.

Gene expression analysis by massively parallel signature sequencing (MPSS) on microbead arrays

We describe a novel sequencing approach that combines non-gel-based signature sequencing with in vitro cloning of millions of templates on separate 5 microm diameter microbeads. After constructing a microbead library of DNA templates by in vitro cloning, we assembled a planar array of a million template-containing microbeads in a flow cell at a density greater than 3x10(6) microbeads/cm2. Sequences of the free ends of the cloned templates on each microbead were then simultaneously analyzed using a fluorescence-based signature sequencing method that does not require DNA fragment separation. Signature sequences of 16-20 bases were obtained by repeated cycles of enzymatic cleavage with a type IIs restriction endonuclease, adaptor ligation, and sequence interrogation by encoded hybridization probes. The approach was validated by sequencing over 269,000 signatures from two cDNA libraries constructed from a fully sequenced strain of Saccharomyces cerevisiae, and by measuring gene expression levels in the human cell line THP-1. The approach provides an unprecedented depth of analysis permitting application of powerful statistical techniques for discovery of functional relationships among genes, whether known or unknown beforehand, or whether expressed at high or very low levels.

In vitro cloning of complex mixtures of DNA on microbeads: physical separation of differentially expressed cDNAs

We describe a method for cloning nucleic acid molecules onto the surfaces of 5-micrometer microbeads rather than in biological hosts. A unique tag sequence is attached to each molecule, and the tagged library is amplified. Unique tagging of the molecules is achieved by sampling a small fraction (1%) of a very large repertoire of tag sequences. The resulting library is hybridized to microbeads that each carry approximately 10(6) strands complementary to one of the tags. About 10(5) copies of each molecule are collected on each microbead. Because such clones are segregated on microbeads, they can be operated on simultaneously and then assayed separately. To demonstrate the utility of this approach, we show how to label and extract microbeads bearing clones differentially expressed between two libraries by using a fluorescence-activated cell sorter (FACS). Because no prior information about the cloned molecules is required, this process is obviously useful where sequence databases are incomplete or nonexistent. More importantly, the process also permits the isolation of clones that are expressed only in given tissues or that are differentially expressed between normal and diseased states. Such clones then may be spotted on much more cost-effective, tissue- or disease-directed, low-density planar microarrays.

Thermodynamic phase diagram of the quantum hall skyrmion system

We numerically study the interacting quantum Hall Skyrmion system based on the Chern-Simons action. By noticing that the action is invariant under global spin rotations in the spin space with respect to the magnetic field direction, we obtain the low-energy effective action for a many-Skyrmion system. Performing extensive molecular dynamics simulations, we establish the thermodynamic phase diagram for a many-Skyrmion system.

Evidence for the role of high density lipoproteins in mediating the antioxidant effect of estrogens

Estrogens possess strong antioxidant effects in vitro, but in vivo studies in humans have yielded conflicting results. Little is known regarding factors that mediate the antioxidant effect of estrogens in vivo. In this study the potential role of high density lipoprotein (HDL) was examined. The antioxidant effect of estradiol-17beta (E2) added to low density lipoprotein (LDL) was lost after dialysis. In contrast, the antioxidant effect of E2 added to HDL was conserved after dialysis, suggesting that E2 was bound to HDL. Binding of E2 to LDL increased after esterification (especially to long chain fatty acids). In the presence of HDL, an increased amount of E2 was transferred to LDL. E2-17 ester was as potent as E2 in preventing LDL oxidation in vitro, but 3,17-diesters were not as effective (E2=E2-17 ester>E2-3 ester>E2-3,17 diester). This was also supported by experiments which showed that estrogens with masked 3-OH groups were not effective as antioxidants. These studies provide evidence that HDL could facilitate the antioxidant effect of E2 through initial association, esterification and eventual transfer of E2 esters to LDL. Therefore it is critical that HDL peroxidation parameters be evaluated in subjects receiving estrogen replacement therapy.

In vitro characterization of the anti-human cytomegalovirus activity of PMEA (Adefovir)

PMEA [9-[2-(phosphonomethoxy)ethyl]adenine; adefovir] has shown anti-cytomegalovirus activity in animal models and in preliminary human trials. PMEA diphosphate (PMEApp), the active antiviral metabolite of PMEA, is a potent inhibitor of human cytomegalovirus (HCMV) DNA polymerase. PMEA is efficiently taken up and phosphorylated to PMEApp in numerous human cell lines. In vitro replication of wild type and drug resistant HCMV clinical isolates is effectively inhibited by PMEA. PMEA in combination with other anti-HCMV agents shows additive inhibition of HCMV replication.

Conversion of 1-[((S)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosine to cidofovir by an intracellular cyclic CMP phosphodiesterase

Cidofovir (HPMPC) [1-[(S)-3-hydroxy-2-(phosphonomethoxy)propyl]-cytosine] is an acyclic nucleotide analog with potent and selective activity against herpesviruses. The prodrug, cyclic HPMPC (cHPMPC) [1-[((S)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl) methyl]cytosine], has antiviral activity similar to that of the parent compound but exhibits reduced toxicity in animal models. cHPMPC is converted to cidofovir by a cellular cyclic CMP phosphodiesterase (EC 3.1.4.37) which hydrolyzes a variety of substrates, including adenosine 3',5'-cyclic monophosphate (cAMP) and cytidine 3',5'-cyclic monophosphate (cCMP). The K(m) and Vmax values for hydrolysis of cHPMPC by cCMP phosphodiesterase purified from human liver are 250 microM and 0.66 nmol.min-1.unit-1, respectively. These values are similar to the K(m) and Vmax values for cAMP (23 microM and 1.16 nmol.min-1.unit-1, respectively) and cCMP (75 microM and 2.32 nmol.min-1.unit of enzyme-1, respectively). The catalytic efficiency (Vmax/K(m) ratio) of this enzyme for the cHPMPC substrate is only 10- to 20-fold lower than those for the natural cyclic nucleotides, indicating that cHPMPC is a viable intracellular substrate for the human enzyme. Kinetic analysis indicates that cHPMPC, cAMP, and cCMP are competitive with respect to each other and that they are hydrolyzed by the same enzyme. cHPMPC is hydrolyzed to cidofovir in all primary human cell systems tested, including those derived from target organs that might be infected in patients with human cytomegalovirus (HCMV) disease. Importantly, hydrolysis of cHPMPC is not diminished in cells infected with HCMV.