Age-related changes in glycine receptor subunit composition and binding in dorsal cochlear nucleus

Age-related hearing loss, presbycusis, can be thought of, in part, as a slow progressive peripheral deafferentation. Previous studies suggest that certain deficits seen in presbycusis may partially result from functional loss of the inhibitory neurotransmitter glycine in dorsal cochlear nucleus (DCN). The present study assessed age-related behavioral gap detection changes and neurochemical changes of postsynaptic glycine receptor (GlyRs) subunits and their anchoring protein gephyrin in fusiform cells of young (7-11 months) and aged (28-33 months) Fischer brown Norway (FBN) rats. Aged rats showed significantly (20-30 dB) elevated auditory brainstem-evoked response thresholds across all tested frequencies and worse gap detection ability compared to young FBN rats. In situ hybridization and quantitative immunocytochemistry were used to measure GlyR subunit message and protein levels. There were significant age-related increases in the alpha(1) subunit message with significant age-related decreases in alpha(1) subunit protein. Gephyrin message and protein showed significant increases in aged DCN fusiform cells. The pharmacologic consequences of these age-related subunit changes were assessed using [3H] strychnine binding. In support of the age-related decrease of alpha(1) subunit protein levels in DCN, there was a significant age-related decrease in the total number of GlyR binding sites with no significant change in affinity. These age-related changes may reflect an effort to reestablish a homeostatic balance between excitation and inhibition impacting on DCN fusiform cells by downregulation of inhibitory function in the face of an age-related loss of peripheral input. Age-related decrease in presynaptic glycine release results in altered subunit composition and this may correlate with loss of temporal coding of the aged fusiform cell in DCN. The previously reported role for gephyrin in retrograde intracellular receptor subunit trafficking could contribute to the alpha(1) decrease in the face of increased message.

Novel F-releasing composite with improved mechanical properties

In recent years, the authors have been developing novel fluoride-releasing dental composites containing ternary zirconium fluoride chelates. The aim of this study was to improve the physical and mechanical properties of these composites by improving the formulation of the monomers and photoinitiators. The hypothesis was that reduction of hydrophilic monomers and improvement of the photoinitiators could reduce water sorption and significantly increase the mechanical properties of the composite. The degree of conversion of the composites containing different compositions of photoinitiators was studied by Fourier transform near-infrared spectroscopy (FT-NIR). Ten experimental composites containing different compositions of ethoxylated bisphenol-A dimethacrylate (EBPADMA), 1,6-hexanediol dimethacrylate (HDDMA), triethylene glycol dimethacrylate (TEGDMA), and 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy) phenyl]-propane (BisGMA) were tested for flexural strength, viscosity, and water sorption. The experimental composite containing 20% synthesized fluoride-releasing monomer, 30% BisGMA, 30% EBPADMA, and 20% HDDMA showed significantly higher fluoride release and recharge, but physical and mechanical properties similar to those of the control composite containing 40% BisGMA, 40% EBPADMA, and 20% HDDMA.

A novel mouse model of human breast cancer stem-like cells with high CD44+CD24-/lower phenotype metastasis to human bone

Abstract #4155

Background: At present, our understanding of the development of bone metastasis is limited. Therefore, little progress has been made in preventing skeletal metastasis in the breast cancer patient. A satisfactory animal model that avoids the species-specific factor and simultaneously shares similarities to the clinical pathophysiological progression of breast cancer metastasizing to bone is unavailable. A subpopulation (CD44+/CD24-/lower) of breast cancer cells possesses stem/progenitor cell properties (cancer stem-like cell). CD44 potentiates the adherence of metastatic breast cancer cells to bone marrow endothelial cells. In the present study, we used hepatocyte growth factor to enhance the proportion of CD44+/CD24-/lower subpopulation in the human breast cancer cell line MDA-MB-231. We used these human breast cancer stem-like cells and implantation of human bone to build a novel human-source model of human breast cancer skeletal metastasis.
 Methods: The human breast cancer cell line MDA-MB-231 was cultured in serum-free DMEM-F12 supplemented with growth factors. Cells in different subpopulations were separated by Percoll gradient centrifugation and incubated in the presence of 50 ng/mL hepatocyte growth factor. The proportion of CD44+/CD24-/lower subpopulation in the human breast cancer cell line MDA-MB-231 was detected with flow cytometry. Before injection with human breast cancer stem-like cells, the experimental animals were implanted with human bone in the right or left dorsal flanks. Animals in Groups A, B, and C were injected with 1 X 105, 1 X 106 human breast cancer stem-like cells, and 1 X 106 parental MDA-MB-231 cells, respectively. A positive control group (D) without implantation of human bone (non-human source model) was also injected with 1 X 106 MDA-MB-231 cells. A group of negative controls (E) with human bone implantation was injected with isotonic sodium chloride. For each group, Micro-SPECT was performed at weeks 4 and 7, and all animals were sacrificed at week 8. Immunohistochemistry was performed for CD34, CD105, SMA, CD44, CD24, CK, CXCR4, and OPN. mRNA levels of CD44, CD24, CXCR4, and OPN in bone metastasis tissues were analyzed by real-time quantitative polymerase chain reaction.
 Results: New vessels and connective tissue were found on the surface of implanted human bones and cells stained positive for antibodies against human CD105, SMA, and CD34, indicating that implanted human bones were viable and functional. Histologic and immunohistochemical analysis confirmed the metastases as cancer cells. Importantly, the results demonstrated that cells in implanted human bones of group B, which received 1 X 106 cancer stem-like cells, stained strongly positive for CD44, CXCR4, and OPN, whereas that of other groups showed no or minimum staining. Moreover, group B had the highest incidence of human bone metastasis (77.8%, P = 0.0230) and no accompaniment of other tissue metastasis. The real-time polymerase chain reaction (PCR) showed an increase of CD44 mRNA in metastatic bone tissues in group B compared with that of groups C and D (15.2- and 21.1-fold, respectively). The mRNA levels of CXCR4 and OPN (8.4- and 28.4-fold, respectively) in bone metastasis tissues of group B were all higher than that of groups C and D (4.8- and 11.6-fold; respectively). The levels of CD24 mRNA in group B were lowest, measuring only 30 percent of that in groups C and D.
 Conclusion: This study indicates that in the novel human source model of breast cancer, breast cancer stem-like cells demonstrate a higher human bone-seeking ability, which may contribute to increase metastasis incidence and attenuate species-specific influences. Its mechanism might be related to the higher expressions of CD44, CXCR4 and OPN, and the lower expression of CD24 in breast cancer stem-like cells. The model shares more similarities with clinical pathological features of bone metastatic patients. It will be helpful for further study of the mechanisms and subclinical diagnosis of bone metastasis.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4155.

Brain cancer survival in Kentucky: 1996-2000

This is a report of brain cancer survival patterns in certain Area Development Districts (ADDs) in Kentucky, the state, and the nation. Brain cancer is of national and regional concern as it is a disease of high case fatality rates and relatively short survival. Comparisons for survival were made between the U.S.A. and the state. Kentucky has higher brain cancer mortality rates than the U.S.A., but significantly better cause-specific survival (p < 0.05). In order to examine within state variations for brain cancer survival, data organized for the fifteen ADDs from the state's central cancer registry were used. The analytic focus of this analysis were three regions expressly: the Purchase ADD (location of the Paducah Gaseous Diffusion Plant), the Green River ADD (the location of elevated brain cancer mortality rates), and the Kentucky River ADD (comprising counties that each have significantly more than the state average of persons living below the national poverty level). We found no evidence of lower survival for brain cancer among the poorer region of the state. The western districts were found to have lower cause-specific survival than the state (p < 0.05) and the U.S.A. Such a regional variation alerts population-based researchers to consider varying survival trends within the state's population.

First heart sound detection for phonocardiogram segmentation

This paper presents an algorithm for accurate and improved detection of the first heart sound S<inf>1</inf>for heart sound cardiac cycle segmentation under noisy environments. The proposed algorithm integrates an S<inf>1</inf>/S<inf>2</inf>selection step and an S<inf>1</inf>identification step. An adaptive sub-level tracking algorithm based on wavelet transform is proposed to separate the S<inf>1</inf>and S<inf>2</inf>from other components such as murmurs and noises. This is followed by a detection procedure based on Shannon energy to reject the overlapping interference so that the peaks of S<inf>1</inf>and S<inf>2</inf>can be detected. Criteria of time interval, energy and phonocardiogram (PCG) collecting position are used to identify S<inf>1</inf>with respect to the beginning of each cardiac cycle. Experimental results show that the proposed algorithm leads to an efficient segmentation of PCG cycle. Due to its simplicity and fast implementation, the method can be deployed clinically for further analysis and eventual use.

Regulation of vascular nitric oxide in vitro and in vivo; a new role for endogenous hydrogen sulphide?

BACKGROUND AND PURPOSE

The aim of these experiments was to evaluate the significance of the chemical reaction between hydrogen sulphide (H2S) and nitric oxide (NO) for the control of vascular tone.

EXPERIMENTAL APPROACH

The effect of sodium hydrosulphide (NaHS; H2S donor) and a range of NO donors, such as sodium nitroprusside (SNP), either alone or together, was determined using phenylephrine (PE)-precontracted rat aortic rings and on the blood pressure of anaesthetised rats.

KEY RESULTS

Mixing NaHS with NO donors inhibited the vasorelaxant effect of NO both in vitro and in vivo. Low concentrations of NaHS or H2S gas in solution reversed the relaxant effect of acetylcholine (ACh, 400 nM) and histamine (100 microM) but not isoprenaline (400 nM). The effect of NaHS on the ACh response was antagonized by CuSO(4) (200 nM) but was unaffected by glibenclamide (10 microM). In contrast, high concentrations of NaHS (200-1600 microM) relaxed aortic rings directly, an effect reduced by glibenclamide but unaffected by CuSO4. Intravenous infusion of a low concentration of NaHS (10 micromol kg(-1) min(-1)) into the anaesthetized rat significantly increased mean arterial blood pressure. L-NAME (25 mg kg(-1), i.v.) pretreatment reduced this effect.

CONCLUSIONS AND IMPLICATIONS

These results suggest that H2S and NO react together to form a molecule (possibly a nitrosothiol) which exhibits little or no vasorelaxant activity either in vitro or in vivo. We propose that a crucial, and hitherto unappreciated, role of H2S in the vascular system is the regulation of the availability of NO.

Examining the paradoxical relation between number of spikes and gaze amplitude in abducens neurons

During head-unrestrained gaze shifts, the number of spikes in the burst of abducens neurons increases with gaze amplitude, even when corrected for the component of the discharge related to the change in eye position. We examine this paradoxical dissociation between the number of spikes and eye amplitude, which occurs because eye amplitude in the head saturates for larger gaze shifts. First, we show that the extra spikes are unlikely to be due to antagonist muscle loading because the abducens neurons are completely silent during large gaze shifts when the muscle acts as an antagonist. Next, we divide the firing rate profile of abducens neurons into terms that represent signals related to eye position, velocity, and acceleration; a d.c. offset term specifying the firing associated with straight-ahead gaze; and a slide term, which compensates for the zero of the oculomotor plant. Then we examine the contribution of each term to the number of spikes recorded. A comparison of the number of spikes with the integral of the fitted function, combining all of the terms, for the duration of the burst reveals that the simulation captures much of the actual data. However, even a model with a slide term cannot reproduce the nonlinear relationship of the number of spikes with amplitude that characterizes large gaze shifts.

CSF hypocretin-1 levels in restless legs syndrome

CSF hypocretin-1 levels at 6 pm did not significantly differ between patients with restless legs syndrome (RLS) and control subjects as measured by direct radioimmunoassay and after acid extraction. The authors did not observe significant differences between early onset and late onset RLS. Hypocretin-1 levels did not correlate with RLS severity or polysomnographic measures. These results contrast with previous findings reporting significantly increased CSF hypocretin-1 in the late evening and mostly in early onset RLS.

Search for charmless B --> VV decays

We have studied two-body charmless decays of the B meson into the final states rho(0)rho(0), K(*0)rho(0), K(*0)K(*0), K(*0)K(*0), K(*+)rho(0), K(*+)K(*0), and K(*+)K(*-) using only decay modes with charged daughter particles. Using 9.7x10(6) BB pairs collected with the CLEO detector, we place 90% confidence level upper limits on the branching fractions (1.4-14.1)x10(-5), depending on final state and polarization.

Search for the familon via B(+/-) --> pi+/-X(0), B(+/-) --> K(+/-)X(0), and B(0) --> K(0)(S)X(0) decays

We have searched for the two-body decay of the B meson to a light pseudoscalar meson h = pi(+/-),K+/-,K(0)(S) and a massless neutral feebly interacting particle X(0) such as the familon, the Nambu-Goldstone boson associated with a spontaneously broken global family symmetry. We find no significant signal by analyzing a data sample containing 9.7x10(6) BBbar mesons collected with the CLEO detector at the Cornell Electron Storage Ring, and set 90% C.L. upper limits italicB(B(+/-) --> h(+/-)X(0)) = 4.9x10(-5) and italicB(B(0) --> K(0)(S)X(0)) = 5.3x10(-5). These limits correspond to a lower bound of approximately 10(8) GeV on the family symmetry breaking scale with vector coupling involving the third generation of quarks.

Hadronic mass moments in inclusive semileptonic B meson decays

We have measured the first and second moments of the hadronic mass-squared distribution in B-->X(c)l nu, for P(lepton)>1.5 GeV/c. We find <M(2)(X)-M macro(2)(D)> = 0.251+/-0.066 GeV(2), <(M(2)(X)-<M(2)(X)>)(2)> = 0.576+/-0.170 GeV(4), where M macro(D) is the spin-averaged D meson mass. From that first moment and the first moment of the photon energy spectrum in b-->s gamma, we find the heavy quark effective theory parameter lambda(1) (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) to be -0.24+/-0.11 GeV(2). Using these first moments and the B semileptonic width, and assuming parton-hadron duality, we obtain absolute value of V(cb) = 0.0404+/-0.0013.

Branching fraction and photon energy spectrum for b --> s gamma

We have measured the branching fraction and photon energy spectrum for the radiative penguin process b-->s gamma. We find Beta(b-->s gamma) = (3.21+/-0.43+/-0.27(+0.18)(-0.10))x10(-4), where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, <E( gamma)> = 2.346+/-0.032+/-0.011 GeV, and <E(2)(gamma)>-<E(gamma)>(2) = 0.0226+/-0.0066+/-0.0020 GeV(2), where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) the heavy quark effective theory parameter Lambda = 0.35+/-0.08+/-0.10 GeV.

First measurement of gamma(D*(+))

We present the first measurement of the D*(+) width using 9/fb of e(+)e(-) data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the Cornell Electron-positron Storage Ring beam spot to measure the energy release distribution from the D*(+)-->D(0)pi(+) decay. We find gamma(D*(+)) = 96+/-4 (stat)+/-22 (syst) keV. We also measure the energy release in the decay and compute Delta m identical with m(D*(+))-m(D(0)) = 145.412+/-0.002 (stat)+/-0.012 (syst) MeV/c(2).

Induced recovery of hypoxic phrenic responses in adult rats exposed to hyperoxia for the first month of life

1. Adult rats exposed to hyperoxia for the first month of life have permanently attenuated ventilatory and phrenic nerve responses to hypoxia. We tested the hypothesis that the blunted hypoxic phrenic response in hyperoxia-treated rats (inspired O(2) fraction, F(I,O2) = 0.6 for 28 post-natal days) could be actively restored to normal by intermittent (alternating 12 % O(2)/air at 5 min intervals; 12 h per night for 1 week) or sustained (12 % O(2) for 1 week) hypoxia. 2. Phrenic responses to isocapnic hypoxia (P(a,O2) = 60, 50 and 40 +/- 2 mmHg) were assessed in the following groups of anaesthetized, vagotomized adult Sprague-Dawley rats (age 4 months), treated with a neuromuscular blocking agent and ventilated: control, hyperoxia-treated and hyperoxia-treated exposed to either intermittent or sustained hypoxia as adults. Experiments on intermittent and sustained hypoxia-treated rats were performed on the morning following hypoxic exposures. 3. Both intermittent and sustained hypoxia enhanced hypoxic phrenic responses in hyperoxia-treated rats when expressed as minute phrenic activity (P < 0.05). Increases in phrenic burst amplitude during hypoxia were greater in hyperoxia-treated rats after intermittent hypoxia (P < 0.05), and a similar but non-significant trend was observed after sustained hypoxia. Hypoxia-induced changes in phrenic burst frequency were not significantly different among groups. 4. The estimated carotid body volume in control rats (11.5 (+/- 0.7) x 10(6) microm(3)) was greater than in the other treatment groups (P < 0.05). However, carotid body volume was significantly greater in hyperoxia-treated rats exposed to sustained hypoxia (6.3 (+/- 0.3) x 10(6) microm(3); P < 0.05) compared to hyperoxia-treated rats (3.3 (+/- 0.2) x 10(6) microm(3)) or hyperoxia-treated rats exposed to intermittent hypoxia (3.8 (+/- 0.3) x 10(6) microm(3)). 5. Hypoxic phrenic responses in hyperoxia-treated rats 1 week after intermittent hypoxia were similar to responses measured immediately after intermittent hypoxia, indicating persistent functional recovery. 6. The results indicate that diminished hypoxic phrenic responses in adult rats due to hyperoxia exposure for the first 28 post-natal days can be reversed by intermittent or sustained activation of the hypoxic ventilatory control system. Although the detailed mechanisms of functional recovery are unknown, we suggest that sustained hypoxia restores carotid chemoreceptor sensitivity, whereas intermittent hypoxia primarily augments central integration of synaptic inputs from chemoafferent neurons.

Immunomodulating activity of CVT-E002, a proprietary extract from North American ginseng (Panax quinquefolium)

The activity of CVT-E002, an aqueous extract containing mainly oligosaccharides and polysaccharides from North American ginseng (Panax quinquefolium), as an immunobooster on murine spleen cells and peritoneal macrophages, was studied in-vitro. CVT-E002 stimulated the proliferation of normal mouse spleen cells, of which the major responding subpopulation was identified as B lymphocytes. CVT-E002 also activated peritoneal exudate macrophages leading to enhanced interleukin-1 (IL-1), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) production. In addition, CVT-E002 stimulated in-vivo immunoglobulin G (IgG) production in treated mice. These results identify some of the immunomodulating activities of CVT-E002 and suggest its use clinically for the modulation of immune responses.

A polymorphism in the human timeless gene is not associated with diurnal preferences in normal adults

The effect of a single nucleotide polymorphism, a glutamine to arginine amino acid substitution in the human Timeless gene (Q831R, A2634G), on diurnal preferences was studied in a random sample of normal volunteers enrolled in a population-based epidemiology study of the natural history of sleep disorders. We genotyped 528 subjects for this single nucleotide polymorphism and determined morningness-eveningness tendencies using the Horne-Ostberg questionnaire. Our results indicate that Q831R Timeless has no influence on morningness- eveningness tendencies in humans.

Synthesis of N-propargylphenelzine and analogues as neuroprotective agents

A series of N(1)- and N(2)-propargylphenelzine derivatives and analogues (1-7) was synthesized. In addition to their activity as monoamine oxidase inhibitors, two of the compounds, N(1)- and N(2)-propargylphenelzines (3 and 6), were found to be potent at preventing DSP-4-induced noradrenaline (NA) depletion in mouse hippocampus, suggesting that they have neuroprotective properties.

Search for the decay upsilon(1S) --> gammaeta(')

We report on a search for the radiative decay Upsilon(1S)-->gammaeta(') in 61.3 pb(-1) of data taken with the CLEO II detector at the Cornell Electron Storage Ring. Three decay chains were investigated, all involving eta(')-->pi(+)pi(-)eta, followed by eta-->gammagamma, eta-->pi(0)pi(0)pi(0), or eta-->pi(+)pi(-)pi(0). We find no candidate events in any of the three cases and set a combined upper limit of 1.6x10(-5) at 90% C.L., significantly smaller than the previous limit. We compare our result to other radiative Upsilon decays, to radiative J/psi decays, and to theoretical predictions.