Plasmon mediated coherent population oscillations in molecular aggregates

The strong coherent coupling of quantum emitters to vacuum fluctuations of the light field offers opportunities for manipulating the optical and transport properties of nanomaterials, with potential applications ranging from ultrasensitive all-optical switching to creating polariton condensates. Often, ubiquitous decoherence processes at ambient conditions limit these couplings to such short time scales that the quantum dynamics of the interacting system remains elusive. Prominent examples are strongly coupled exciton-plasmon systems, which, so far, have mostly been investigated by linear optical spectroscopy. Here, we use ultrafast two-dimensional electronic spectroscopy to probe the quantum dynamics of J-aggregate excitons collectively coupled to the spatially structured plasmonic fields of a gold nanoslit array. We observe rich coherent Rabi oscillation dynamics reflecting a plasmon-driven coherent exciton population transfer over mesoscopic distances at room temperature. This opens up new opportunities to manipulate the coherent transport of matter excitations by coupling to vacuum fields.

Monolayer-Based Single-Photon Source in a Liquid-Helium-Free Open Cavity Featuring 65% Brightness and Quantum Coherence

Solid-state single-photon sources are central building blocks in quantum information processing. Atomically thin crystals have emerged as sources of nonclassical light; however, they perform below the state-of-the-art devices based on volume crystals. Here, we implement a bright single-photon source based on an atomically thin sheet of WSe2 coupled to a tunable optical cavity in a liquid-helium-free cryostat without the further need for active stabilization. Its performance is characterized by high single-photon purity (g(2)(0) = 4.7 ± 0.7%) and record-high, first-lens brightness of linearly polarized photons of 65 ± 4%, representing a decisive step toward real-world quantum applications. The high performance of our devices allows us to observe two-photon interference in a Hong-Ou-Mandel experiment with 2% visibility limited by the emitter coherence time and setup resolution. Our results thus demonstrate that the combination of the unique properties of two-dimensional materials and versatile open cavities emerges as an inspiring avenue for novel quantum optoelectronic devices.

Combined Low Dose of Ketamine and Social Isolation: A Possible Model of Induced Chronic Schizophrenia-Like Symptoms

Introduction

Identifying a feasible model of chronic schizophrenia would be valuable for studying the possible underlying mechanism and to investigate emerging treatments. Our hypothesis starts from the observation that combining ketamine with isolation could result in long-lasting neuro-psychological deficits and schizophrenia-like features; thus, it could probably be used as the first model of chronic schizophrenia that emphasizes the characteristic of having a multifactorial etiology

Objectives

creation of a complex animal model capable of exhibiting the multifactorial origin and manifestation of schizophrenia.

Methods

we investigated the effects of ketamine administration combined with isolation in inducing schizophrenia-like symptoms in male albino rats and the brain reactive oxygen species levels.

Results

Our results showed that the number of lines crossings in the open field test, the number of open arm entries in the elevated plus maze, and the spontaneous alternations percentage in the Y-maze were significantly lower in the ketamine + isolation group compared to both the control and ketamine + social housing group (p < 0.05). Furthermore, the ketamine + isolation intervention significantly increased the MDA levels and decreased the GPx levels both in the hippocampus and the cortex of the rats. In addition, our premise of creating a model capable of exhibiting both positive and negative symptoms of schizophrenia was also based on adding the aripiprazole treatment to a group of rats

Conclusions

combining ketamine with isolation could result in long-lasting neuro-psychological deficits and schizophrenia-like features

Disclosure

No significant relationships.

STAT6 links IL-4/IL-13 stimulation with pendrin expression in asthma and chronic obstructive pulmonary disease

Signaling through the interleukin-4/interleukin-13 (IL-4/IL-13) receptor complex is a crucial mechanism in the development of bronchial asthma and chronic obstructive pulmonary disease (COPD). In bronchial epithelial cells, this signaling pathway leads to changes in the expression levels of several genes that are possibly involved in protection against and/or pathogenesis of these diseases. The expression of pendrin (SLC26A4), a candidate for the latter category, is upregulated by IL-4/IL-13 and leads to overproduction of mucus and increased viscosity of the airway surface liquid (ASL). Therefore, elucidating the transcriptional regulation of pendrin could aid in the development of new pharmacological leads for asthma and/or COPD therapy. Here we show that IL-4/IL-13 significantly increased human pendrin promoter activity in HEK-Blue cells but not in STAT6-deficient HEK293 Phoenix cells; that mutation of the STAT6 binding site (N(4) GAS motif) rendered the promoter insensitive to IL-4/IL-13; and that addition of the N(4) GAS motif to an IL-4/IL-13-unresponsive sequence of the human pendrin promoter conferred sensitivity to both ILs.

STAT6 links IL-4/IL-13 stimulation with pendrin expression in asthma and chronic obstructive pulmonary disease

Signaling through the interleukin-4/interleukin-13 (IL-4/IL-13) receptor complex is a crucial mechanism in the development of bronchial asthma and chronic obstructive pulmonary disease (COPD). In bronchial epithelial cells, this signaling pathway leads to changes in the expression levels of several genes that are possibly involved in protection against and/or pathogenesis of these diseases. The expression of pendrin (SLC26A4), a candidate for the latter category, is upregulated by IL-4/IL-13 and leads to overproduction of mucus and increased viscosity of the airway surface liquid (ASL). Therefore, elucidating the transcriptional regulation of pendrin could aid in the development of new pharmacological leads for asthma and/or COPD therapy. Here we show that IL-4/IL-13 significantly increased human pendrin promoter activity in HEK-Blue cells but not in STAT6-deficient HEK293 Phoenix cells; that mutation of the STAT6 binding site (N(4) GAS motif) rendered the promoter insensitive to IL-4/IL-13; and that addition of the N(4) GAS motif to an IL-4/IL-13-unresponsive sequence of the human pendrin promoter conferred sensitivity to both ILs.

Non-destructive and quantitative imaging of a nano-structured microchip by ptychographic hard X-ray scanning microscopy

We used hard X-ray scanning microscopy with ptychographic coherent diffraction contrast to image a front-end processed passivated microchip fabricated in 80 nm technology. No sample preparation was needed to image buried interconnects and contact layers with a spatial resolution of slightly better than 40 nm. The phase shift in the sample is obtained quantitatively. With the additional knowledge of the elemental composition determined in parallel by X-ray fluorescence mapping, quantitative information about specific nanostructures is obtained. A significant enhancement in signal-to-noise ratio and spatial resolution is achieved compared to conventional hard X-ray scanning microscopy.

Fully automated immunoassay for quantitative determination of FXIII

Coagulation factor XIII (FXIII) is essential for clot stabilization. Deficiency of FXIII is associated with a risk of bleeding and impaired wound healing. Substitution therapy with FXIII remedies for patients with low plasma levels of FXIII requires diagnostic quantification of the factor before and during therapy. Here, we describe a prototype of a preliminary research immunoassay for quantification of FXIII antigen on automated coagulation instruments. The prototype assay is based on a monoclonal antibody (mAb) directed against FXIII A chain, whereas the mAbs are coupled to latex particles. FXIII in a plasma specimen causes agglutination of the latex particles, which can be quantified turbidimetrically. Performance data of the assay prototype processed on BCS® XP and Sysmex® CA-1500 instruments demonstrate a good correlation to the Berichrom® factor XIII activity assay1 from Siemens Healthcare Diagnostics (r = 0.94). Results: Comparability of instruments was excellent (r = 0.98). Coefficients of variation of total imprecision measurements ranged from 2.2 to 3.4%. Linearity was excellent over the range tested (12–121% FXIII). Analytical sensitivity was 0.51% FXIII on BCS XP and 0.44% FXIII on Sysmex CA-1500, respectively. No interference (> 10% bias) was observed with haemoglobin (up to 400 mg/dl), cholesterol (up to 300 mg/dl), bilirubin (up to 60 mg/dl) or triglycerides (up to 3000 mg/dl). Conclusion: The preliminary research assay prototype has the potential for excellent analytical sensitivity, precision, and dynamic range suitable to measure reliably FXIII antigen levels in human plasma.

Coherent x-ray diffraction imaging with nanofocused illumination

Coherent x-ray diffraction imaging is an x-ray microscopy technique with the potential of reaching spatial resolutions well beyond the diffraction limits of x-ray microscopes based on optics. However, the available coherent dose at modern x-ray sources is limited, setting practical bounds on the spatial resolution of the technique. By focusing the available coherent flux onto the sample, the spatial resolution can be improved for radiation-hard specimens. A small gold particle (size <100 nm) was illuminated with a hard x-ray nanobeam (E=15.25 keV, beam dimensions approximately 100 x 100 nm2) and is reconstructed from its coherent diffraction pattern. A resolution of about 5 nm is achieved in 600 s exposure time.

Successful use of rifampicin for Hispanic foreign-born patients with latent tuberculosis infection

SETTING

Four months of rifampicin (4R) is recommended for the treatment of latent tuberculosis infection (LTBI), although data regarding its use are limited. The majority of tuberculosis (TB) cases in the USA occur among foreign-born persons.

OBJECTIVE

To determine tolerability, hepatotoxicity and completion rates associated with 4R among foreign-born persons.

DESIGN

We retrospectively evaluated 4R treatment among a cohort of predominantly Hispanic foreign-born LTBI patients in four Middle-Tennessee public health clinics from February 2000 to February 2004. Patients' charts were reviewed to abstract demographic, social and clinical data. 4R completion rates, new symptoms and hepatotoxicity (serum aminoalanine transferase >or=120U/l with gastrointestinal symptoms or >or=200 regardless of symptoms) were evaluated.

RESULTS

Of 749 patients treated, 571 (76%) completed 4R. Among all subjects, Hispanics had a lower risk of non-completion (OR 0.6, 95%CI 0.4-0.7) than non-Hispanics. Among non-Hispanic subjects, the risk of non-completion was higher for Blacks than non-Blacks (adjusted OR 2.6, 95%CI 1.5-4.7), but was lower for foreign-born than non-foreign-born subjects (adjusted OR 0.5, 95%CI 0.2-0.9). During treatment, 85 subjects (11%) developed new symptoms, and hepatotoxicity occurred in three patients.

CONCLUSION

With high completion rates and minimal side effects, 4R is a favorable LTBI treatment regimen for Hispanic and other foreign-born patients.

Effectiveness of moulded insoles in reducing plantar pressure in diabetic patients

For an effective prevention of foot sole ulcers in diabetic patients, the Bioengineering and Signal processing group of the Electronics Department of the Pontificia Universidad Javeriana developed a novel method for the computer assisted design and production of therapeutic insoles, integrating several technologies, such as: CAD/CAM registration of pressure on the foot sole, Podoscopy, and an expert system based on knowledge. The afore mentioned method allows topographical modeling of the insoles starting by the digitization in 3D of a cast of the foot sole surface of the patient and its computer assisted design taking into account the recommendations of the knowledge based system. The aim of this study was to evaluate the effect on plantar pressure distribution of different insoles prescribed and manufactured with various techniques on a random group of patients with diabetes mellitus in the early stages of the disease. Four different types of insoles were manufactured by methods available in the market and by the computer model system proposed on a previous research, which was used in order to design and manufacture one of the insoles evaluated. The differences between the four types of insoles were established by comparing their effectiveness in plantar pressure reduction.

The "PAROTEC" foot pressure measurement system and its calibration procedures (2005)

The Parotec is an electronic system used for measuring the pressure distribution on the plantar surface of the foot within the shoe on a number of diabetic patients under various conditions. It is believe that the design of the pressure vessel for applying static and dynamic pressure on the transducers is an important contribution to the validation of the Parotec system. The main advantages of the Parotec system is the hydro cell technology however the number of sensors is no enough for recording pressure in areas at-risk such as the 5th toe, MTH1, MTH4 and MTH5, according to the results from the X-ray study.

Intermittent administration of the circulating form of human parathyroid hormone (hPTH-1-37) prevents bone loss in ovariectomized rats

The circulating hormonal form of human parathyroid hormone (hPTH-1-37) has been assessed in vitro as well as in vivo in the ovariectomized rat, a model for postmenopausal osteoporosis. In vitro, hPTH-1-37 induces a dose-dependent cAMP formation and increases vitality as well as alkaline phosphatase activity in UMR106 osteosarcoma cells. Differentiation and proliferation of osteoclasts in rat bone marrow-derived stem cell preparations are decreased. Daily hPTH-1-37 s.c. administration in ovariectomized rats for 60 days results in augmented formation of new bone, in amplified femural bone density, and in thickening of the calvaria.

The position of the centres of the sensors of the Parotec pressure measurement insoles system related to the anatomy centres of the metatarsal heads by means of radiological records

This study pretend to establish the anthropometric relationship between the position of osseous prominences (metatarsal heads, proximal and distal phalanxes bones) of the feet in a group of diabetic patients, and the position of the sensors of the electronic German Parotec insoles system, located in the same areas to register the plantar pressure distribution in standing position by using RXs. The aims of this study were: a) to establish the position of the centres of the sensors of the Parotec insoles related to the centres of the metatarsal heads and distal ends of the proximal phalanges and the proximal ends of the distal phalanges phalanxes of the feet, in a group of 12 diabetic subjects wearing different type of shoes, by means of radiological records, in order to answer the following questions: (1) Can the Parotec insoles designed for registering plantar pressure distribution on diabetic German people be used for measuring pressure distribution on a group of 12 diabetic type 1 and type 2 Colombian people evaluated in this study? (2) Are those bones landing according to the Parotec sensor position? (3) Which would be the proper distribution of the Parotec sensors for this group of subjects? b) To establish if the use of different types of footwear (sports, conventional and orthopaedic footwear) with the Parotec electronic insoles can influence the position of the osseous prominences in relation to the position of the sensors that register the pressure in these areas.

Manufacturing of gene-modified cytotoxic T lymphocytes for autologous cellular therapy for lymphoma

BACKGROUND

The production of therapeutic T-cell populations for adoptive immunotherapy of cancer requires extensive ex vivo cell processing, including the isolation or creation of Ag-specific T cells and their subsequent propagation to clinically relevant numbers. These procedures must be performed according to the principles of current good manufacturing practices (cGMP) for phase I clinical trials to ensure the identity, purity potency and safety of the cellular product. In this report we describe our approach to manufacturing and characterizing bulk populations of gene-modified autologous T cells for use in treating follicular lymphoma.

METHODS

PBMC from healthy donors, obtained after informed consent, were stimulated in vitro with Ab to CD3epsilon (OKT3) and recombinant human IL-2 and then electroporated with plasmid DNA containing a human CD19-specific chimeric Ag receptor (CAR) gene and HSV-1 thymidine kinase (TK) gene. Stably transfected cells were selected in cytocidal concentrations of hygromycin B over multiple 14-day stimulation culture cycles and then cryopreserved. Vials of cryopreserved/selected T cells were used to initiate T-cell expansion cultures to produce cell products for clinical infusion. These cultures were characterized for phenotype, function and suitability for use in adoptive immunotherapy studies.

RESULTS

Our results demonstrate that bulk populations of gene-modified T cells derived from peripheral blood of healthy donors express CD19+ chimeric Ag receptor at low levels and can specifically lyse CD19+ target cells in vitro. These cells display a differentiated T-effector phenotype, are sensitive to ganciclovir-mediated killing and display a non-transformed phenotype. TCR Vbeta usage indicated that all populations tested were polyclonal. Ex vivo cell expansion from cryopreserved cell banks is sufficient to produce doses of between 5 x 10(9) and 1 x 10(10) cells/run. One of three transductions resulted in a population of cells that was not suitable for infusion but was identified during release testing. No populations displayed any evidence of bacterial, fungal or mycoplasma contamination.

DISCUSSION

We have established a manufacturing strategy that is being used to produce T cells for a phase I clinical trial for follicular lymphoma. Genetically modified T cells have been characterized by cell-surface marker phenotype, functional activity against CD19+ targets and requisite safety testing. These pre-clinical data confirm the feasibility of this approach to manufacturing T-cell products.

Angiodysplasia as a cause of Gastrointestinal Bleeding in Childhood

Whereas in adults angiodysplasia is a frequent cause of gastrointestinal bleeding, in children this disorder is extremely rare. A 7 10/12 year old girl is presented suffering over 3-4 months from mild but recurrent rectal bleeding. Blood count and serum ferritin and transferrin levels were normal. The rectosigmoideoscopy revealed a rectal lesion, which was confirmed histologically as angiodysplasia. Pathological investigation of the biopsies included HE staining and immunohistological staining of endothelial cells with anti-CD34 and anti-von Willebrand factor. A follow-up period of three years revealed spontaneous regression of the angiodysplastic lesion at the rectosigmoideal localisation, which could be confirmed by endoscopy.

CONCLUSION

The outcome of the few pediatric patients described in the literature was reviewed. Due to the lack of conclusive understanding of the nature of this extremely rare vascular disorder and the variable outcome described, a wait and see attitude should be assumed in cases of less clinical affection.

Acute Hypercalcemia of the Heart (“Bony Heart”)

Cardiac abnormalities as a sign of hyperparathyroidism are common. A spectacular pitfall of peracute extended myocardiac hypercalcemia is reported. The history of a 30-year-old woman included symptoms such as insufficiency of the kidneys since childhood, secondary hyperparathyroidism, and hemodialysis for approximately 4 years. After kidney transplantation, the patient died from progressive heart failure. Three days before she died, CT showed a nearly white heart, and myocardial scintigraphy revealed a total infarction. The autopsy revealed a heart of normal size but with a weight of 590 g and with nearly bony texture. The histologic examination showed extended calcifications of the entire myocardium, thus explaining these findings. Laboratory photographs and electron microscopic images will be demonstrated. The metabolic pathogenesis of tertiary hyperparathyroidism and calciphylaxis is discussed. "Malignant" progression after kidney transplantation is stressed.

P-Selectin expression, platelet aggregates, and platelet-derived microparticle formation are increased in peripheral arterial disease

Platelet volume has been reported to be increased in vascular disease. Therefore, we studied the relationship of mean platelet volume and platelet count as well as flow cytometrically measured platelet size and platelet function in 50 patients with peripheral arterial disease and 50 healthy volunteers. Platelet activation was measured by P-selectin expression analysis on resting and on stimulated platelets, and the determination of platelet aggregates and platelet-derived microparticles using flow cytometry. P-Selectin expression on platelets was significantly elevated in patients suffering from peripheral arterial disease (all P<0.0001). Platelet aggregates (P<0.0001) and platelet-derived microparticles (P<0.0001) were significantly higher in the patient group compared with controls, whereas mean platelet volume and platelet count showed no significant differences. Platelet count was inversely related to mean platelet volume in patients and controls (r = -0.43, P<0.001). The present study supports the hypothesis of platelet hyperreactivity and circulating activated platelets in peripheral arterial disease. Mean platelet volume, and platelet count cannot be used as predictive markers for platelet activation in peripheral arterial disease patients.

Colony stimulating factors regulate nitric oxide and prostaglandin E2 production in rat cartilage chondrocytes

Colony stimulating factors (CSFs) are now widely used in cancer treatment and immunological disease therapy. Both granulocyte CSF (G-CSF) and granulocyte-macrophage CSF (GM-CSF) are used to increase neutrophil counts in Felty syndrome. In the present study, the effects of macrophage CSF (M-CSF), G-CSF, GM-CSF and interleukin-3 (IL-3) (10 ng/ml) on the production of nitric oxide and prostaglandin E2 (PGE2) by cartilage explants were examined over 24 and 48 h. The effects of these CSFs were also measured in combination with IL-1 beta (10 ng/ml). M-CSF, GM-CSF and IL-3 had no effect on nitrite production. However, both IL-1 beta and G-CSF caused a significant increase (p < 0.05) in nitrite levels at 48 h. NG-L-arginine-methyl-ester was used to inhibit nitrite production induced by G-CSF and this implicated nitric oxide synthase activity. When G-CSF and IL-1 beta were used in a combined treatment, nitrite levels were significantly increased (p < 0.05) at both 24 and 48 h. Both IL-3 alone and in combination with IL-1 beta caused elevated PGE2 production in this model. PGE2 levels were also significantly increased by stimulation with GM-CSF and IL-3 combined with IL-1 beta. These findings demonstrate that GM-CSF, G-CSF and IL-3 may induce changes in the production of inflammatory mediators such nitric oxide and PGE2 in cartilage chondrocytes. Hence, CSFs may play a vital role in influencing cartilage metabolism in rheumatoid and osteoarthritis.

Replication factor C disengages from proliferating cell nuclear antigen (PCNA) upon sliding clamp formation, and PCNA itself tethers DNA polymerase delta to DNA

Replication factor C (RF-C) and proliferating cell nuclear antigen (PCNA) assemble a complex, called sliding clamp, onto DNA. The clamp in turn loads DNA polymerases (pol) delta and epsilon to form the corresponding holoenzymes, which play an essential role in replication of eukaryotic chromosomal DNA and in several DNA repair pathways. To determine the fate of RF-C after loading of PCNA onto DNA, we tagged the RF-C subunit p37 with a protein kinase A recognition motif, so that the recombinant five-subunit RF-C complex could be 32P-labeled and quantitatively detected in femtomolar amounts. Nonspecific binding of RF-C to DNA was minimized by replacing the p140 subunit with an N-terminally truncated p140 subunit lacking the previously identified nonspecific DNA binding domain. Neither of these modifications impaired the clamp loading activity of the recombinant RF-C. Using gel filtration techniques, we demonstrated that RF-C dissociated from the DNA after clamp loading or pol delta holoenzyme assembly, while PCNA or PCNA.pol delta complex remained bound to DNA. PCNA catalytically loaded onto the template-primer was sufficient by itself to tether pol delta and stimulate DNA replication. The readdition of RF-C to the isolated PCNA.DNA complex did not further stimulate pol delta DNA synthesis. We conclude that pol delta holoenzyme consists of PCNA and pol delta core and that RF-C serves only to load PCNA clamp.

Pathogenesis of murine enterovirus myocarditis: virus dissemination and immune cell targets

In order to identify organ and cellular targets of persistent enterovirus infection in vivo, immunocompetent mice (SWR/J, H-2q) were inoculated intraperitoneally with coxsackievirus B3 (CVB3). By use of in situ hybridization for the detection of enteroviral RNA, we show that CVB3 is capable of inducing a multiorgan disease. During acute infection, viral RNA was visualized at high levels in the heart muscle, pancreas, spleen, and lymph nodes and at comparably low levels in the central nervous system, thymus, lung, and liver. At later stages of the disease, the presence of enteroviral RNA was found to be restricted to the myocardium, spleen, and lymph nodes. To characterize infected lymphoid cells during the course of the disease, enteroviral RNA and cell-specific surface antigens were visualized simultaneously in situ in spleen tissue sections. In acute infection, the majority of infected spleen cells, which are located primarily at the periphery of lymph follicles, were found to express the CD45R/B220+ phenotype of pre-B and B cells. Whereas viral RNA was also detected in certain CD4+ helper T cells and Mac-1+ macrophages, no enteroviral genomes were identified in CD8+ cytotoxic/suppressor T cells. Later in disease, the localization of enteroviral RNA revealed a persistent type of infection of B cells within the germinal centers of secondary follicles. In addition, detection of the replicative viral minus-strand RNA intermediate provided evidence for virus replication in lymphoid cells of the spleen during the course of the disease. These data indicate that immune cells are important targets of CVB3 infection, providing a noncardiac reservoir for viral RNA during acute and persistent myocardial enterovirus infection.

[Intra-abdominal cystic lymphangioma and mesenteric cysts as a cause of abdominal discomfort]

Although intra-abdominal lymphangioma and mesenteric cysts are rare benign tumours, they have to be considered in the differential diagnosis of abdominal pain. Differentiation of these lesions is important, because lymphangiomas may follow a proliferative and invasive course. From 1979 to 1993 four patients with intra-abdominal cystic lymphangiomas and two with mesenteric cysts underwent operations in our surgical department. Five of these six patients had abdominal symptoms, ranging from unspecific abdominal pain to acute clinical abdomen. In all cases surgical enucleation or resection and histological classification were necessary before final diagnosis was possible.

Human cytomegalovirus induces JC virus DNA replication in human fibroblasts

JC virus, a human papovavirus, is the causative agent of the demyelinating brain disease progressive multifocal leucoencephalopathy (PML). PML is a rare but fatal disease which develops as a complication of severe immunosuppression. Latent JC virus is harbored by many asymptomatic carriers and is transiently reactivated from the latent state upon immunosuppression. JC virus has a very restricted host range, with human glial cells being the only tissue in which it can replicate at reasonable efficiency. Evidence that latent human cytomegalovirus is harbored in the kidney similar to latent JC virus led to the speculation that during episodes of impaired immunocompetence, cytomegalovirus might serve as helper virus for JC virus replication in otherwise nonpermissive cells. We show here that cytomegalovirus infection indeed leads to considerable JC virus DNA replication in cultured human fibroblasts that are nonpermissive for the replication of JC virus alone. Cytomegalovirus-mediated JC virus replication is dependent on the JC virus origin of replication and T antigen. Ganciclovir-induced inhibition of cytomegalovirus replication is associated with a concomitant inhibition of JC virus replication. These results suggest that reactivation of cytomegalovirus during episodes of immunosuppression might lead to activation of latent JC virus, which would enhance the probability of subsequent PML development. Ganciclovir-induced repression of both cytomegalovirus and JC virus replication may form the rational basis for the development of an approach toward treatment or prevention of PML.

Volume changes in high-affinity calcium binding of the sarcoplasmic reticulum calcium-transport enzyme

The effect which hydrostatic pressure exerts on the hydrolysis of dinitrophenyl phosphate and nitrophenyl phosphate by the sarcoplasmic reticulum calcium-transport enzyme was determined. Activation volumes for substrate hydrolysis at saturating and non-saturating concentrations of calcium were determined and used to evaluate volume increments for initial calcium binding. A reaction scheme in which two unidirectional substrate-driven reactions transfer high-affinity into low-affinity calcium-binding sites was applied to determine binding-volume increments. It has been inferred from the pressure dependence of the volume-generating function, defined as the difference between the reciprocal reaction rates of the saturated and the unsaturated enzyme, that calcium binding proceeds in two steps. The two associated binding constants are endowed with large binding-volume increments of opposite signs (+84 to +207 ml/mol and -3 to -136 ml/mol). Under different experimental conditions, with respect to the temperature, degree of calcium saturation and absence or presence of Me2SO, they add up to the same integral volume increment of 73 +/- 3.5 ml/mol for the entry of two calcium ions into the reaction cycle. In aqueous media, the two binding constants contribute about equally to binding and to the observed binding-volume increment. The presence of Me2SO strongly favours the first binding step. The size of the integral volume increment is in line with that determined for the interaction of calcium with calmodulin [Kupke, D.W. & Dorrier, T.E. (1986) Biochem. Biophys. Res. Commun. 38, 199-204].

Activation and binding volumes of the sarcoplasmic reticulum transport enzyme activated by calcium or strontium

The effect of pressure on the hydrolysis of dinitrophenyl phosphate (DnpP) and p-nitrophenyl phosphate (NpP) by the sarcoplasmatic reticulum transport enzyme in permeabilized and native closed vesicles activated by calcium or strontium, respectively, in aqueous and Me2SO-containing media has been studied. At atmospheric pressure, the enzyme in permeabilized vesicles, saturated with respect to substrates and activating ions, hydrolyzes DnpP ten times faster than NpP; for both substrates, calcium activation exceeds that by strontium only a little (20%). In aqueous media the enzyme displays, under all activating conditions, an almost identical curvilinear relationship between the logarithm of enzyme activity and pressure. The data were analysed on the basis of a simplified reaction scheme, in which two unidirectionally proceeding substrate-driven pressure-dependent reactions (k2, k4) cyclically transfer high-affinity into low-affinity binding sites which are assumed to be in equilibrium with either calcium or strontium. The fitting procedure yielded two sets of positive activation volumes delta V2* = 90-110 ml/mol and delta V4* = 15-25 ml/mol. Substrate specificity, as well as the effect of temperature, are exclusively localized in the pressure-independent rate constants k'2 and k'4. Considerable different pressure/activity relations characterized by a single activation volume of 20 ml/mol were obtained for the strongly suppressed substrate hydrolysis of native closed vesicles. At atmospheric pressure DnpP hydrolysis of open vesicles is inhibited by Me2SO, while NpP hydrolysis is considerably activated, irrespective of its activation by calcium or strontium. In the presence of 22.5% Me2SO, the activation volumes are reduced by 50-70 ml/mol. The rate constants of DnpP and NpP hydrolysis are either augmented or reduced by rising Me2SO concentrations, depending on the corresponding supporting substrate. Me2SO has only a slight effect on the pressure dependence of substrate hydrolysis by native vesicles. The small activation volume observed for the activity of native vesicles could be assigned on account of the simplified reaction scheme of the slow reaction step k4, by which the enzyme is transferred from its low-affinity into its high-affinity binding state. Volume changes connected with the binding of calcium or strontium to the luminal binding site of the enzyme were deduced from the observed activation volume and the computed volume change of the slow reaction step (delta V4*).

Blockage of a pump-related calcium-efflux pathway in light sarcoplasmic reticulum vesicles by Mops

Mops, used as a proton buffer, specifically enhances the accumulation of calcium or strontium by light sarcoplasmic reticulum vesicles driven by ATP or dinitrophenylphosphate as energy-yielding substrates when calcium-precipitating agents are absent. The enhancement of ion uptake by Mops is much greater for strontium than for calcium and is further increased when potassium is replaced by sodium as the dominant monovalent cation. Mops affects neither the activity of the calcium- or strontium-activated transport enzyme nor the active accumulation of calcium in the presence of oxalate, i.e. when the pump runs unidirectionally forward. Passive calcium and strontium efflux rates of approximately 40-50 nmol.mg-1.min-1 are considerably reduced when histidine/glycerophosphate or Tris/maleate are exchanged for Mops. The observed passive efflux rates and their modulation by Mops are too small, in relation to the rate of ion influx, to account for either the relatively small calcium and strontium load in the absence of precipitating agents or for its modulation by Mops. The results imply that the pump itself mediates ion efflux dependent on pump activity and the different degree of saturation of lumenal ion-binding sites by calcium and strontium, as well as their susceptibility to Mops.

The adeno-associated virus rep gene suppresses herpes simplex virus-induced DNA amplification

Herpes simplex virus (HSV) induces within the host cell genome DNA amplification which can be suppressed by coinfection with adeno-associated virus (AAV). To characterize the AAV functions mediating this effect, cloned AAV type 2 wild-type or mutant genomes were transfected into simian virus 40 (SV40)-transformed hamster cells together with the six HSV replication genes (encoding UL5, UL8, major DNA-binding protein, DNA polymerase, UL42, and UL52) which together are necessary and sufficient for the induction of SV40 DNA amplification (R. Heilbronn and H. zur Hausen, J. Virol. 63:3683-3692, 1989). The AAV rep gene was identified as being responsible for the complete inhibition of HSV-induced SV40 DNA amplification. Likewise, rep inhibited origin-dependent HSV replication. rep neither killed the transfected host cells nor interfered with gene expression from the cotransfected amplification genes. This points to a specific interference with HSV-induced DNA amplification.

[Psychological aspects of sleep related disorders of respiratory control]

An impaired ability to concentrate, loss of intellectual performance, and changes in personality are frequently-mentioned psychological symptoms of sleep apnoea. Apnea-associated disturbances of sleep structure as well as nocturnal cerebral hypoxia are possible causes. Twenty men and two women with an average age of 51.5 years underwent psychological testing. The average apnea index was 36 (range 11 to 92). The following psychodiagnostic procedures were used for screening; attention-strain test (d2) to measure short term concentration ability, numbers-connecting test (ZVT) for the evaluation of cognitive processing speed as an indication of intellectual performance, the Freiburg Personality Inventory FPI-R for assessing personality traits. As compared with the standard random sample of the d2, our patients' ability to concentrate over a period of five minutes does not seem to be impaired. Deficits in patients with sleep apnea are more likely to be found in the care of long-term concentration, especially in monotonous situations. The mean IQ score of our sample (93) is rather low as compared with the mean value of the age-matched sample (100). Patients with an Apnea index greater than 30 tended to have lower IQ-values (87.4) than those with less severe sleep apnea (97). Older patients had significantly lower age-corrected figures (87.2) than younger patients (98). Younger patients with high apnea activity (greater than median) had significantly (ANOVA: interaction alpha = 0.01) lower IQ scores (84.8) than younger patients with less severe sleep apnea (107). Sleep apnea seems to impair cognitive processing speed. Our sample turned out to be normal with respect to the twelve personality traits measured by means of the FPI-R.(ABSTRACT TRUNCATED AT 250 WORDS)