Humic colloid-borne natural polyvalent metal ions: dissociation experiment

The natural association nature of the humic colloid-borne trace elements is investigated. Rare earth elements (REE) Th and U are chosen as naturally occurring representatives and chemical homologues for actinides of different oxidation states present in nuclear waste. Tri- and tetravalent elements in two investigated Gorleben groundwaters (Gohy-532 and -2227) almost exclusively occur as humic or fulvic colloid-borne species. Their desorption behavior from colloids is examined in the unperturbed groundwater (pH approximately 8) under anaerobic conditions (Ar/1% CO2) by addition of a chelating cation exchanger resin. Particularly, the dissociation process of naturally occurring Eu(III) in the groundwater is compared with the Eu(III) desorption from its humate complex prepared with purified Aldrich humic acid in a buffered aqueous solution at pH approximately 8. The Eu(III) dissociation from the groundwater colloids is found to be considerably slower than found for the humate complex synthesized in the laboratory. This suggests that under natural aquatic conditions the Eu(III) binding in colloids is chemically different from the simple humate complexation as observed in the laboratory experiment. The colloid characterization bythe size exclusion chromatography (SEC) and the flow field-flow fractionation (FFFF) indicates that natural colloid-borne trace elements are found predominantly in colloids of larger size (>15 nm in size), while Eu(III) in its humate complex is found mainly in colloids of hydrodynamic diameters <5 nm. The slower desorption kinetics and the larger colloid size suggest that the polyvalent metal ion binding in natural humic colloids is associated to polynucleation with other co-present trace metal ions. Radiotracer experiments reveal that isotopic equilibria with the naturally colloid-borne trace elements are not attained within a period of more than 100 days, indicating irreversible binding of at least a part of colloid-borne polyvalent trace elements. The different kinetic properties of colloid-bound Eu(III) are discussed taking the aqueous speciation based on thermodynamic data into account.

XAFS investigation of the structure of aqueous thorium(IV) species, colloids, and solid thorium(IV) oxide/hydroxide

X-ray absorption fine structure (XAFS) spectroscopy at the Th L3 edge is applied for the characterization of crystalline, anhydrous ThO(2)(cr), microcrystalline ThO(2).xH(2)O(s), amorphous ThO(n)(OH)(4-2n).xH(2)O(am), aqueous Th(IV) solutions, and colloidal suspensions up to p(c)H 3.7. The microcrystalline, possibly hydrated thorium dioxide, is formed at p(c)H 1.5-2.5 by precipitation from suspensions of 16-23 nm thorium dioxide colloids. The solubility data determined for this solid is several orders of magnitude lower than the values for amorphous Th(IV) hydroxide or hydrous oxide. The EXAFS spectrum of the isolated microcrystalline particles shows that their structure is different from that of anhydrous crystalline ThO(2)(cr) and amorphous ThO(n)(OH)(4-2n).xH(2)O(am) precipitated at higher pH and dried at room temperature. The solubility measured for the amorphous Th(IV) precipitate is comparable to that previously reported for a solid prepared in a similar manner. In other solubility studies with amorphous Th(IV) hydroxide or hydrous oxide, considerably higher thorium concentrations are measured at p(c)H 3.5-5. The aqueous speciation is made by EXAFS for solutions prepared by careful coulometric titration under comparable conditions (p(c)H and thorium concentration). The spectra of these solutions demonstrate the presence of a large amount of Th(IV) polynuclear species or colloids of small size, having a highly asymmetric Th-O coordination. The EXAFS spectrum of these colloids is similar to that of the amorphous solid.

Antibacterial, antitumor and hemolytic activities of alpha-helical antibiotic peptide, P18 and its analogs

The alpha-helical antibiotic peptide (P18: KWKLFKKIPKFLHLAKKF-NH2) designed from the cecropin A(1-8)-magainin 2 (1-12) hybrid displayed strong bactericidal and tumoricidal activity without inducing hemolysis. The effect of the Pro9 residue at central position of P18 on cell selectivity was investigated by Pro9 --> Leu or Pro9 --> Ser substitution. Either substitution markedly reduced the antibacterial activity of P18 and increased hemolysis, although it did not significantly affect cytotoxicity against human transformed tumor and normal fibroblast cells. These results suggest that a proline kink in alpha-helical antibiotic peptide P18 serves as a hinge region to facilitate ion channel formation on bacterial cell membranes and thus plays an important role in providing high selectivity against bacterial cells. Furthermore, to investigate the structure-antibiotic activity relationships of P18, a series of N- or C-terminal deletion and substitution analogs of P18 were synthesized. The C-terminal region of P18 was related to its antibiotic activity and alpha-helical conformation on lipid membranes rather than N-terminal one. Higher alpha-helicity of the peptides was involved in the hemolytic and antitumor activity rather than antibacterial activity. Except for [L9]-P18 and [S9]-P18, all the designed peptides containing a Pro residue showed potent antibacterial activity, although they did not induce a cytolytic effect against human erythrocyte and normal fibroblast cells at the concentration required to kill bacteria. In particular, P18 and some analogs (N-1, N-2, N-3, N-3L and N-4L) with potent bactericidal and tumoricidal activity and little or no normal cell toxicity may serve as an attractive candidate for the development of novel anti-infective or antitumor agents.

A new measure of the impact of managed care on healthcare markets

BACKGROUND

Most studies of managed care impact have used health maintenance organization (HMO) penetration or index of competition as the marker of managed care impact. However, little empirical evidence has been found to support the validity of these or other measures in current use. In addition, as managed care evolves to forms other than HMOs and managed care penetration in large metropolitan areas approaches 100% of commercially insured patients, the utility of the most commonly used measure, HMO penetration, will decrease still further.

OBJECTIVES

To provide a preliminary analysis of the use of premiums as a measure of market impact of managed care.

STUDY DESIGN

Retrospective analysis (quartile, correlation, multiple-variable linear regression) of publicly available datasets.

METHODS

Labor market-adjusted HMO premiums from 3 publicly available sources, for the 56 largest metropolitan areas in the United States, were compared with penetration and index of competition as predictors of the dependent market variable, hospital bed-days per 1000 population.

RESULTS

Health maintenance organization premiums in the Federal Employees Health Benefits Program emerged as the best predictor of HMO market impact. Average HMO premiums reported in the Interstudy database and for the Medicare+Choice program also outperformed penetration or index of competition in relating to several commonly available markers of competition such as bed-days per 1000.

CONCLUSIONS

Premiums charged by HMOs are a useful measure of the impact of managed care on healthcare markets in large metropolitan areas.

Ocular responses to head rotations during mirror viewing

The gain of the human vestibuloocular reflex (VOR) is influenced by the proximity of the object of regard. In six human subjects, we measured the eye rotations induced by passive, sinusoidal, horizontal head rotations at 2.0 Hz during binocular fixation of a stationary far target at 7 m; a stationary target close to the subject's near point of fixation (<15 cm); and the bridge of the subject's own nose, viewed through a mirror positioned so that, for each subject, the angle of vergence was similar to that during viewing of the near target. The median gain of compensatory eye movements for the group of subjects during far viewing was 0.99 (range 0.80-1.04), during near viewing was 1.21 (range 0.88-1.47), and during mirror viewing was 0.85 (range 0.71-1.01). The gain during near and mirror viewing was significantly different for each subject (P < 0.001) even though the vergence angles were similar. The lower gain values during mirror viewing can be attributed to the geometric relationship between the head rotation, the position of the eyes in the head, and the movement of the subject's virtual image in the mirror. To determine whether visually mediated eye movements were responsible for the observed gain values, we conducted a control experiment in which subjects were rotated using a sum-of-sines stimulus that minimized the effects of predictive visual tracking; differences of gain values between near- and mirror-viewing conditions were similar to those during rotation at 2 Hz. We conclude that, in these experiments, target proximity and vergence angle were not the key determinants of gain of the visuo-vestibular response during head rotation while viewing a near target but that contextual cues from motion vision were more important in generating the appropriate response.

Frequent epigenetic inactivation of RASSF1A in human bladder carcinoma

Allelic deletion or transcriptional silencing of RASSF1, a putative tumor suppressor at 3p21.3, has been found in a considerable proportion of lung, breast, and ovarian cancers. In this study, we analyzed the expression and mutation status of three RASSF1 isoforms (-A, -B, and -C) in 55 primary bladder carcinomas and 10 bladder and prostate cancer cell lines. The RASSF1A transcript was not found in 80% (4 of 5) and 100% (4 of 4) of bladder and prostate cell lines, respectively. Compared with normal bladder tissues, loss or significant reduction of RASSF1A was identified in 62% (34 of 55) of primary bladder carcinomas and 10 (83%) of 12 matched sets showed tumor-specific alteration of RASSF1A expression. Moreover, loss or abnormal down-regulation of RASSF1A correlated with advanced tumor stage. RASSF1B was undetectable in 60% (3 of 5) of bladder cell lines and in 31% (17 of 55) of primary tumors, but none of these tumors showed altered expression exclusively in RASSF1B. RASSF1C transcript was detected in all cell lines and primary tumors we examined. Expression of RASSF1A and RASSF1B was reactivated in all nonexpressor cell lines by treatment with the demethylating agent 5-aza-2'-deoxycytidine. Bisulfite DNA sequencing analysis revealed that aberrant hypermethylation at the CpG island in the RASSF1A promoter is strongly associated with the loss of RASSF1A expression in cell lines and uncultured primary tumors. Methylation-specific PCR and BstUI digestion analyses also demonstrated that 97% (33 of 34) of RASSF1A-nonexpressing primary tumors are methylated. Although somatic mutations were not identified in RASSF1 transcripts expressed in unmethylated tumors, 24% (9 of 37) of methylated cell lines and primary tumors showed detectable reductions in genomic levels of RASSF1, suggesting that RASSF1A inactivation might be caused by both epigenetic and genetic mechanisms in a subset of bladder tumors. Together, our data suggest that RASSF1A inactivation may play a critical role in the malignant progression of human bladder carcinomas.

Use of alternative therapies in older outpatients in the United States and Japan: prevalence, reporting patterns, and perceived effectiveness

BACKGROUND

The purpose of this study was to determine the prevalence, patterns of reporting, and perceived effectiveness of alternative medical therapies (ATs) among older white American, African American, and Japanese outpatients.

METHODS

This study used a questionnaire to interview participants (N = 593; age, >59 y), who were outpatients of geriatric outpatient clinics in Saint Louis, Missouri, and Tokyo, Japan (white Americans, n = 180; African Americans, n = 106; and Japanese, n = 307).

RESULTS

Use of >1 AT was greatest among older Japanese (74.3%), followed by white Americans (61.1%) and African Americans (47.2%; p <.001). The most common ATs used among the Japanese (and significantly more than the white and African American groups) were lifestyle diet, herbal therapy, massage, acupressure, and acupuncture. The white and African American groups were more frequent users of relaxation techniques and spiritual healing compared with the Japanese group. Contrary to prior studies of the general population, the use of >1 AT did not correlate with any sociodemographic variables. Reported use of ATs to doctors was low but similar in all three groups (white Americans = 48%, African Americans = 42%, and Japanese = 46%). Perceived effectiveness was high but similar in all three groups (white Americans = 85%, African Americans = 92%, and Japanese = 84%). Although chronic conditions were common reasons for use of ATs, nonmedical reasons (e.g., general health or religious reasons) were also common.

CONCLUSIONS

Use of ATs was greater in Japan than in the United States, but for both countries, use by older persons was greater than previous reports of the general population. Because sociodemographic variables do not predict use, and reported use to doctors is low and perceived effectiveness is high, increased awareness and understanding about ATs by health care professionals seems imperative.

Time-resolved laser fluorescence spectroscopy study of the sorption of Cm(III) onto smectite and kaolinite

For long-term performance assessment of nuclear waste repositories knowledge concerning interactions of actinides with mineral surfaces is imperative. The mobility and bioavailability of released radionuclides is strongly dependent on sorption/desorption processes onto mineral surfaces. Therefore it is necessary to characterize the surface species formed and to elucidate the reaction mechanisms involved. The high fluorescence spectroscopic sensitivity of Cm(III) has attracted our interest regarding the complexation process of Cm(III) onto smectite and kaolinite as a model system for the sorption of trivalent actinides in the trace concentration range. We conclude that at low pH Cm(III) is sorbed onto kaolinite and smectite as an outer-sphere complex and retains its complete primary hydration sphere. With increasing pH inner-sphere adsorption onto kaolinite and smectite occurs via the aluminol edge sites. The same evolution of the Cm(III)-clay surface species as a function of pH was observed for both minerals. Starting at a pH > or = 5 we observe the formation of a [triple bond]Al-O-Cm2+(H2O)5 surface complex, which is replaced by a second species at higher pH. The second surface complex may be a monodentate [triple bond]Al-O-Cm+(OH)(H2O)4 species or bidentate [triple bond](Al-O)2-Cm+(H2O)5 species. The Cm(III)/clay surface complexes are characterized bytheir emission spectra (peak maxima at 598.8 and 603.3 nm) and their fluorescence lifetime (both 110 +/- 7 micros). An important result in view of the mobility and bioavailability of radionuclides is that no incorporation of Cm(III) into the bulk clay structure was observed.

Evaluation of transdermal scopolamine as treatment for acquired nystagmus

We conducted an unmasked evaluation of transdermal scopolamine in seven patients with acquired nystagmus for whom other treatments had been unsatisfactory. We measured eye speed and visual acuity before and several hours after starting treatment. Median eye speed decreased slightly in three patients but increased in two; no change in visual acuity occurred in any patient. One patient was unable to tolerate the side effects of scopolamine after two hours, but the others continued the scopolamine treatment for 48 hours; only one reported minor improvement. We conclude that transdermal scopolamine is not likely to be an effective treatment of acquired nystagmus. Patients should be monitored during the first few hours of treatment to determine whether vision is improved or made worse and whether side effects occur.

Size characterization of bentonite colloids by different methods

The size and shape of colloids released from a natural bentonite into a low-mineralized groundwater are investigated using various colloid characterization methods. For the applied methods such as atomic force microscopy (AFM), laser-induced breakdown detection (UBD), photon correlation spectroscopy (PCS), and flow field-flow fractionation coupled to ICP-mass spectrometric detection (FFFF-ICPMS), the respective raw size data have to be corrected in order to consider chemical composition and shape of the colloids as well as instrumental artifacts. Noncontact mode AFM of the bentonite colloids shows disklike shapes of stacked smectite platelets with a mean height-to-diameter proportion (aspect ratio) of approximately 1/10. A broad particle number size distribution is determined by image processing with a mean particle diameter of 73 nm. In agreement with AFM, a broad size distribution is also found by PCS and FFFF-ICPMS. Likewise, mean particle sizes found by LIBD (67 +/- 13 nm) and FFFF-ICPMS (maximum in the number size distribution, approximately 70 nm) are in fair agreement with the AFM data. Somewhathigher values are obtained by PCS, where mean particle diameters of the intensity-weighted size distributions of larger than 200 nm are found (depending on the algorithm used for data processing). The influence of the disklike particle shape on the results of the individual methods is discussed. As a conclusion, the application of different colloid characterization methods is a prerequisite to get complementary information about colloid size and shape, which is essential for the understanding of natural colloidal systems.

Vertical nystagmus in normal subjects: effects of head position, nicotine and scopolamine

We measured gaze stability in darkness of four normal humans using the search coil technique. Subjects were tested first with their heads erect, and then with their heads positioned 180 degrees upside-down. In each position, subjects held their head stationary for one minute, and then actively performed pitch rotations for 20 sec. All subjects showed sustained chin-beating nystagmus in the upside-down position. Each subject showed a significant increase of slow-phase velocity directed towards their brow after 40 sec in the inverted versus erect position. Pitch head rotation had little effect on subsequent nystagmus, except for transient reversal in one subject. The sustained changes of vertical eye drifts induced by 180 deg change of head position suggest that otolithic factors may contribute to vertical nystagmus in normals. The subjects were retested after wearing a nicotine patch for 2 hours. In three subjects, nicotine induced brow-beating nystagmus; adopting a head-hanging position increased this nystagmus in two subjects. In a third session, subjects were tested after wearing a scopolamine patch for 2 hours; results were generally similar to the control condition. We conclude that normal subjects may show chin-beating ("downbeating") nystagmus in a head-hanging position in darkness, reflecting a normal, physiological change in otolithic inputs brought about by the head orientation.

Degradation of focal adhesion proteins paxillin and p130cas by caspases or calpains in apoptotic rat-1 and L929 cells

Immunofluorescence microscopy revealed the rearrangement and gradual dissociation of paxillin from focal adhesion sites during apoptosis. In vitro, cleavage of paxillin by caspase-3 generated a 42-kDa fragment, among other products, while cleavage by calpain generated a different set of fragments. In Rat-1 cells, cleavage of paxillin by caspase-3 was suppressed by zVAD-fmk or zDEVD-cmk, making caspase-3 a likely executioner during etoposide-induced apoptosis. In contrast, the cleavage of paxillin and p130cas in apoptotic L929 cells was blocked by calpain-specific inhibitors, which also reduced the death rate by 23 to 44%. Therefore, The disassembly and degradation of p130cas and paxillin during apoptosis may controlled by both caspases and calpains, depending upon their cellular contexts. Our findings also suggest that focal adhesion proteins paxillin and p130cas take part in integrin-mediated signaling for cell survival, and that their cleavage by caspase and/or calpain may not only disrupt focal adhesion complexes, but may also impede cell survival signaling.

Proliferation in the posterior region of the lens of c-maf-/- mice

PURPOSE

To examine the involvement of the c-maf gene in the proliferation of the lens cells.

METHODS

Eyes of the E13 and E18 stages of the wild-type and c-maf-/- mice were analyzed by BrdU incorporation assay, TUNEL assay and immunocytochemistry using a anti-P27(KIP1) and a anti-P57(KIP2) antibody.

RESULTS

In the E13 and E18 c-maf mutant lens, BrdU-positive cells were detected at the posterior region of the lens. Cell-cycle inhibitor P27(KIP1) and P57(KIP2) were expressed in the equatorial and posterior region of the lens of both wild-type and c-maf-/- lenses.

CONCLUSION

These results suggest that the expression of c-maf is required for differentiation and cell cycle arrest of lens fiber cells. It is also suggested that P27(KIP1) and P57(KIP2) were not involved in the continued proliferation of posterior region of the c-maf-/- lens.

Structure-activity analysis of SMAP-29, a sheep leukocytes-derived antimicrobial peptide

SAMP-29 is a cathelecidin-derived antimicrobial peptide deduced from sheep myeloid mRNA. To elucidate the structural-activity relationship of SMAP-29, several analogues were synthesized and their antibiotic activity was investigated. Compared to parental SMAP-29, SMAP-29(1-17) and [K(22,25,27)]-SMAP-29 retained relatively effective antimicrobial activity (MIC: 1.0-8.0 microM), but resulted in a complete loss of hemolytic activity. Pro-19 --> Ala substitution ([A19]-SMAP-29) in SMAP-29 induced a significant reduction in antibacterial activity. These results suggested that the N-terminal amphipathic alpha-helical region and the C-terminal hydrophobic region of SMAP-29 are responsible for antimicrobial activity and hemolytic activity, respectively, and the central Pro-19 in SMAP-29 plays a critical role in showing improved antibacterial activity. In particular, [K(2,7,13)]-SMAP-29(1-17) showed potent antimicrobial activity under high salt conditions without hemolytic activity. Thus, this short peptide could serve as an attractive candidate for the development of therapeutic antimicrobial drugs. Structural analysis by circular dichroism suggested that SMAP-29 seems to adopt a helix-bend/turn-extended random conformation.

Dextromethorphan affects cocaine-mediated behavioral pattern in parallel with a long-lasting Fos-related antigen-immunoreactivity

In order to understand the underlying mechanisms responsible for the behaviors mediated by dextromethorphan (DM), we examined the effects of DM on locomotor activity and locomotor patterns in mice, and Fos-related antigen immunoreactivity (FRA-IR) of mouse brain following repeated administration of cocaine. Combined treatments (30 min prior to each cocaine administration) with DM dose-dependently decreased locomotor activity for high doses of cocaine (20 mg/kg, i.p./day x 7). DM combinations did not significantly affect hyperactivity for 10 mg cocaine/kg, i.p./day x 7. In contrast, combined treatments with DM increased the locomotor activity for 5 mg cocaine/kg, i.p./day x 7. These results were consistent with alterations in marginal activity. Repeated administration with cocaine or DM increased FRA-IR in the nucleus accumbens (NAc) and striatum which lasted for at least 7 days. Our results suggest that DM exhibits biphasic effects on the locomotor stimulation induced by cocaine, and that locomotor activities are in parallel with FRA-IR of the striatal complex. However, the role of FRA-IR regulated by DM or/and cocaine remains to be further determined.

Expression and Tyrosine Phosphorylation of E-Cadherin, β- and γ-Catenin, and Epidermal Growth Factor Receptor in Cervical Cancer Cells

OBJECTIVES

The cadherin/catenin adhesion complex is fundamentally involved in epithelial cancer invasion and metastasis. Much evidence suggesting that epidermal growth factor (EGF) induced the scattering and invasion of cancer cells, probably by affecting E-cadherin function, has been reported. The present study aimed to confirm the hypothesis that EGF/epidermal growth factor receptor (EGFR) was related with the E-cadherin adhesion system in cervical cancer cells and that EGF might induce tyrosine phosphorylation of beta- and gamma-catenin.

METHODS

Cervical cancer cells were treated for different time durations with 30 ng/ml of EGF. Alteration of the cell morphology was examined by light microscopy and the expression of E-cadherin, beta-catenin, gamma-catenin, EGFR, and activated EGFR was assayed using Western blotting. Tyrosine phosphorylation of beta- and gamma-catenin was also examined using immunoprecipitation.

RESULTS

E-cadherin and EGFR were expressed in CaSki, HT-3, and ME-180 cell lines, which showed epithelial contact growth. The expression of E-cadherin and beta- and gamma-catenin did not change after treatment with EGF. The expression of EGFR decreased and activated EGFR expression increased in 30 min and then decreased subsequently. The simultaneous expression of activated EGFR and tyrosine phosphorylation of beta- and gamma-catenin was found.

CONCLUSIONS

EGF-induced scattering of the E-cadherin-positive cervical cancer cells might be the result of tyrosine phosphorylation of the beta- and gamma-catenin. Phosphorylation of the beta- and gamma-catenin may hamper the adhesive function of the E-cadherin-catenin complex.

Light and brassinosteroid signals are integrated via a dark-induced small G protein in etiolated seedling growth

Plant growth and development are regulated through coordinated interactions between light and phytohormones. Here, we demonstrate that a dark-induced small G protein, pea Pra2, regulates a variant cytochrome P450 that catalyzes C-2 hydroxylation in brassinosteroid biosynthesis. The cytochrome P450 is dark-induced and predominantly expressed in the rapidly elongating zone of etiolated pea epicotyls, where Pra2 is also most abundant. Transgenic plants with reduced Pra2 exhibit a dark-specific dwarfism, which is completely rescued by exogenous brassinolide. Overexpression of the cytochrome P450 results in enhanced hypocotyl growth even in the light, which phenocopies the etiolated hypocotyls. We therefore propose that Pra2 and its orthologs are molecular mediators for the cross-talk between light and brassinosteroids in the etiolation process in plants.

Influence of quinine on catecholamine release evoked by cholinergic stimulation and membrane depolarization from the rat adrenal gland

The present study was attempted to investigate the effect of quinine on secretion of catecholamines (CA) evoked by cholinergic stimulation and membrane depolarization from the isolated perfused rat adrenal gland. The perfusion of quinine (15-150 microM) into an adrenal vein for 60 min produced dose- and time-dependent inhibition in CA secretion evoked by ACh (5.32 x 10(-3) M), high K+ (5.6 x 10(-2) M), DMPP (10(-4) M for 2 min), McN-A-343 (10(-4) M for 2 min), cyclopiazonic acid (10(-5) M for 4 min) and Bay-K-8644 (10(-5) M for 4 min). Also, under the presence of pinacidil (10(-4) M), which is also known to be a selective potassium channel activator, CA secretory responses evoked by ACh, high potassium, DMPPF McN-A-343, Bay-K-8644 and cyclopiazonic acid were also greatly reduced. When preloaded along with quinine (5 x 10(-5) M) and glibenclamide (10(-6) M), a specific blocker of ATP-regulated potassium channels, CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were recovered as compared to those of quinine-treatment only. Taken together, these results demonstrate that quinine inhibits CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by membrane depolarization through inhibiting influx of extracellular calcium and release in intracellular calcium in the rat adrenomedullary chromaffin cells. These findings suggest that activation of potassium channels may be involved at least in inhibitory action of quinine on CA secretion from the rat adrenal gland.

Oxidative stress and neurodegeneration in prion diseases

Transmissible spongiform encephalopathies (TSEs), also termed prion diseases, are a group of fatal neurodegenerative diseases that affect humans and a number of other animal species. The etiology of these diseases is thought to be associated with the conversion of a normal protein, PrPC, into an infectious, pathogenic form, PrPSc. The PrPSc form shows greater protease resistance than PrPC and accumulates in affected individuals, often in the form of extracellular plaques. The pathogenesis and the molecular basis of neuronal cell death in these diseases are not well understood. Oxidative stress has been proposed to play an important role in the pathogenesis of several neurodegenerative disorders. In the present study, evidence of oxidative stress in scrapie, the archetype disease of the TSEs, is discussed. In addition, the mechanisms whereby oxidative stress could lead to neuronal degeneration are described.

Manipulation of cold atomic collisions by cavity QED effects

We show how the dynamics of collisions between cold atoms can be manipulated by a modification of spontaneous emission times. This is achieved by placing the atomic sample in a resonant optical cavity. Spontaneous emission is enhanced by a combination of multiparticle entanglement together with a higher density of modes of the modified vacuum field, in a situation akin to superradiance. A specific situation is considered and we show that this effect can be experimentally observed as a large suppression in trap-loss rates.

Numerical modeling of humic colloid borne americium (III) migration in column experiments using the transport/speciation code K1D and the KICAM model

The humic colloid borne Am(III) transport was investigated in column experiments for Gorleben groundwater/sand systems. It was found that the interaction of Am with humic colloids is kinetically controlled, which strongly influences the migration behavior of Am(III). These kinetic effects have to be taken into account for transport/speciation modeling. The kinetically controlled availability model (KICAM) was developed to describe actinide sorption and transport in laboratory batch and column experiments. Application of the KICAM requires a chemical transport/speciation code, which simultaneously models both kinetically controlled processes and equilibrium reactions. Therefore, the code K1D was developed as a flexible research code that allows the inclusion of kinetic data in addition to transport features and chemical equilibrium. This paper presents the verification of K1D and its application to model column experiments investigating unimpeded humic colloid borne Am migration. Parmeters for reactive transport simulations were determined for a Gorleben groundwater system of high humic colloid concentration (GoHy 2227). A single set of parameters was used to model a series of column experiments. Model results correspond well to experimental data for the unretarded humic borne Am breakthrough.

Continence efficacy intervention program for community residing women with stress urinary incontinence in Japan

Many women in Japan have lived with urinary incontinence (UI). These women are not willing to visit the hospital with their problem of incontinence. Even if the women consent to a hospital visit, continence education is often very limited and patients may immediately stop looking for further treatment. Programs of effective education are needed. The Continence Efficacy Intervention Program (CEIP) was developed for patients and was designed to circumvent many of the obstacles common to stopping exercise. In this study, a randomized trial was conducted to compare the effectiveness of this program to conventional intervention on exercise continuity. This report describes the study design, intervention program, and outcomes. Subjects were 48 women with stress urinary incontinence (SUI): the mean age was 53.5, the mean weight was 56.6 kg, and the average prevalent year was 6.5 years. The CEIP phone interviews improved exercise continuity and urine loss symptom. Findings suggest that this intervention program is effective and readily available to the community-residing women with SUI.

Ocular oscillations induced by shifts of the direction and depth of visual fixation

Shifts of the point of fixation between two targets aligned on one eye that are located near and far (Müller paradigm) stimulates a combined saccadic-vergence movement. In normal subjects, this test paradigm often induces saccadic oscillations of about 0.3 degrees at 20 to 30 Hz. We measured eye movements using the magnetic search coil technique in 2 patients recovering from viral opsoclonus-myoclonus syndrome, comparing saccadic-vergence responses to the Müller paradigm with conjugate saccades between distant targets. Both patients exhibited intermittent conjugate ocular oscillations of about 4 to 5 degrees amplitude at about 10 Hz. Combined saccadic-vergence movements induced these oscillations twice as often as did conjugate saccades. One patient also exhibited disjunctive ocular oscillations at 10 Hz while sustaining fixation on the near target. The Müller paradigm provides a useful clinical and experimental technique for inducing saccadic oscillations. The probable mechanism is that pontine omnipause neurons, which normally gate saccades, are inhibited during the sustained vergence movement that follows the saccadic component of the response to the Müller paradigm.