Dopamine and beta-band oscillations differentially link to striatal value and motor control

Parkinson's disease is characterized by decreased dopamine and increased beta-band oscillatory activity accompanying debilitating motor and mood impairments. Coordinate dopamine-beta opposition is considered a normative rule for basal ganglia function. We report a breakdown of this rule. We developed multimodal systems allowing the first simultaneous, chronic recordings of dopamine release and beta-band activity in the striatum of nonhuman primates during behavioral performance. Dopamine and beta signals were anticorrelated over seconds-long time frames, in agreement with the posited rule, but at finer time scales, we identified conditions in which these signals were modulated with the same polarity. These measurements demonstrated that task-elicited beta suppressions preceded dopamine peaks and that relative dopamine-beta timing and polarity depended on reward value, performance history, movement, and striatal domain. These findings establish a new view of coordinate dopamine and beta signaling operations, critical to guide novel strategies for diagnosing and treating Parkinson's disease and related neurodegenerative disorders.

Saccharomyces cerevisiae boulardii CNCM I-1079 affects health, growth, and fecal microbiota in milk-fed veal calves

The objective of this study was to investigate the effect of one specific strain of yeast, Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB), on the growth performance, health, and fecal bacterial profile of veal calves. A total of 84 animals were enrolled in an experiment at a commercial veal farm for a total of 7 wk. Calves were fed twice a day with a milk replacer meal during the entire experiment and were randomly assigned to receive daily either SCB supplementation (10 × 10⁹ cfu/d) or a placebo (CON). Individual feed intake and body weight were monitored on a daily and weekly basis, respectively. Fecal samples were collected at arrival to the veal facility (wk 0) and additional samples were taken on d 14 (wk 2) and d 49 (wk 7). These samples were subjected to 16S rRNA gene amplicon sequencing using Illumina MiSeq (Illumina Inc., San Diego, CA) to examine the bacterial profiles and real-time quantitative PCR to quantify Saccharomyces cerevisiae and specific bacterial groups. The significant increase of S. cerevisiae in the feces of SCB calves at wk 2 and 7 compared with wk 0 (respectively 1.7 × 10⁷, 1.2 × 10⁷, and 2.2 × 10⁵ copy number of S. cerevisiae/g of feces) indicates a good survival of that yeast strain along the gastrointestinal tract. Supplementation of SCB did not improve overall growth performance with regard to average daily gain (ADG), final body weight, and feed intake. Nevertheless, a total of 69.1% of nonsupplemented calves had diarrhea and 28.6% experienced severe diarrhea, whereas 50.0% of the calves supplemented with SCB had diarrhea and 9.5% experienced severe diarrhea. With respect to antibiotic use, 89.7% of the diarrheic calves recorded in the CON group were treated, whereas only 66.7% of the SCB diarrheic calves received an antibiotic. In addition, diarrheic calves supplemented with SCB maintained an ADG similar to nondiarrheic animals, whereas the CON diarrheic calves had a significantly lower ADG in comparison with nondiarrheic CON calves. Fecalibacterium was the most predominant bacterial genus in fecal samples of nondiarrheic and diarrheic calves supplemented with SCB, whereas fecal microbiota was predominated by Collinsella in diarrheic calves from the CON group. Live yeast supplementation in milk replacer led to a decrease of diarrhea in milk-fed veal calves and the fecal microbiota of diarrheic calves maintained a healthy community similar to nondiarrheic animals, with Fecalibacterium being the predominant genus.

Radiographic study to assess the reliability of the Gillies approach for biopsy of the superficial temporal artery

Biopsy of the superficial temporal artery is often used in the diagnosis of giant cell arteritis, but at traditional sites there is a risk of injury to the facial nerve. Recently the Gillies incision has been suggested as an alternative means of access for the biopsy, but the anatomical basis of this has not been fully elucidated. We therefore undertook a radiographic review of 150 patients, and examining 300 vessels, to find out. Our results indicated that there is considerable variability in the position of the bifurcation of the superficial temporal artery, and so a Gillies approach may not be reliable, particularly if access to the bifurcation is required.

Chirped-pulse amplification with narrowband pulses

We demonstrate a compact hyperdispersion stretcher and compressor pair that permit chirped-pulse amplification in Nd:YAG. We generate 750 mJ, 0.2 nm FWHM, 10 Hz pulses recompressed to an 8 ps near-transform-limited duration. The dispersion-matched pulse compressor and stretcher impart a chirp of 7300 ps/nm, in a 3 m x 1 m footprint.

High-power picosecond laser pulse recirculation

We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high-power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering-based light sources. We demonstrate up to 40x average power enhancement of frequency-doubled submillijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

Solving the accelerator-condenser coupling problem in a nanosecond dynamic transmission electron microscope

We describe a modification to a transmission electron microscope (TEM) that allows it to briefly (using a pulsed-laser-driven photocathode) operate at currents in excess of 10 mA while keeping the effects of condenser lens aberrations to a minimum. This modification allows real-space imaging of material microstructure with a resolution of order 10 nm over regions several microm across with an exposure time of 15 ns. This is more than six orders of magnitude faster than typical video-rate TEM imaging. The key is the addition of a weak magnetic lens to couple the large-diameter high-current beam exiting the accelerator into the acceptance aperture of a conventional TEM condenser lens system. We show that the performance of the system is essentially consistent with models derived from ray tracing and finite element simulations. The instrument can also be operated as a conventional TEM by using the electron gun in a thermionic mode. The modification enables very high electron current densities in microm-sized areas and could also be used in a nonpulsed system for high-throughput imaging and analytical TEM.

Isotope-specific detection of low-density materials with laser-based monoenergetic gamma-rays

What we believe to be the first demonstration of isotope-specific detection of a low-Z and low density object shielded by a high-Z and high-density material using monoenergetic gamma rays is reported. The isotope-specific detection of LiH shielded by Pb and Al is accomplished using the nuclear resonance fluorescence line of L7i at 478 keV. Resonant photons are produced via laser-based Compton scattering. The detection techniques are general, and the confidence level obtained is shown to be superior to that yielded by conventional x-ray and gamma-ray techniques in these situations.

Stream insect occupancy-frequency patterns and metapopulation structure

An understanding of the distribution patterns of organisms and the underlying factors is a fundamental goal of ecology. One commonly applied approach to visualize these is the analysis of occupancy-frequency patterns. We used data sets describing stream insect distributions from different regions of North America to analyze occupancy-frequency patterns and assess the effects of spatial scale, sampling intensity, and taxonomic resolution on these patterns. Distributions were dominated by satellite taxa (those occurring in <or=10% of sites), whereas the occurrence of core taxa (occurring in >or=90% of sites) determined the overall modality of occupancy-frequency patterns. The proportions of satellite taxa increased with spatial scale and showed positive relationships with sampling intensity (r2=0.74-0.96). Furthermore, analyses of data sets from New York (USA) showed that generic-level assessments underestimated the satellite class and occasionally shifted occupancy-frequency distributions from unimodal to bimodal. Our results indicate that, regardless of species- or generic-level taxonomy, stream insect communities are characterized by satellite species and that the proportion of satellite species increases with spatial scale and sampling intensity. Thus, niche-based models of occupancy-frequency patterns better characterize stream insect communities than metapopulation models such as the core-satellite species hypothesis.

Classical theory of Compton scattering: assessing the validity of the Dirac-Lorentz equation

The Dirac-Lorentz equation describes the dynamics of a classical point charge in an electromagnetic field, accounting for radiative effects in a manifestly covariant and gauge-invariant manner. The validity of this equation is assessed by direct comparison between the Dirac-Lorentz dynamics of an electron subjected to a plane wave in vacuum and the well-known recoil associated with Compton scattering. In the small recoil limit, the classical Dirac-Lorentz is shown to yield the correct momentum transfer. For larger values of the recoil, the quantum scale appears explicitly, and the classical Dirac-Lorentz equation does not properly model this situation, as shown by deriving an exact analytical solution for a monochromatic plane wave of wave number k0 to any order in k0r0, where r0 is the classical electron radius.

Random amplified polymorphic DNA variation among remnant big bluestem (Andropogon gerardii vitman) populations from Arkansas' grand prairie

Random amplified polymorphic DNA (RAPD) analysis was used to characterize genetic diversity and genetic distinctiveness of Andropogon gerardii from remnant Arkansas prairies. Six oligonucleotide primers, which generated 37 RAPD bands, were used to analyse 30-32 plants from six Grand Prairie populations, Baker Prairie (Arkansas Ozarks), two Illinois prairies and two cultivars. Genetic diversity of the Arkansas remnants ranged from 82.7 to 99.3%, with 89% of the total genetic variation within and 11% among populations. The partitioning of genetic variation was consistent with that reported for other outcrossing perennial grasses, using the more conservative allozyme markers. Principal component analysis indicated a northern and southern association within Arkansas' Grand Prairie. Although there was no genetic structuring at the landscape level, the Illinois prairies and cultivars were different from all Arkansas prairies tested. There was significant within-population structuring in four of the seven Arkansas remnants, with a negative relationship between genetic similarity and geographical distance. The three nonstructured populations were from a linear railroad remnant, suggesting different population-level dynamics from nonlinear prairies. The results of this study indicated that small isolated remnant big bluestem populations were not genetically depauperate and that genetic relationships among populations could not be predicted solely on geographical proximity.

Processing and characterization of silver films used to fabricate hollow glass waveguides

Hollow glass waveguides are an increasingly popular fiber for the delivery of high-power IR laser radiation. At CO(2) laser wavelengths the measured and theoretical losses agree, but at the 3-microm Er:YAG laser wavelength the losses remain higher than expected. The reason for this is the surface roughness of the silver film used to form the first layer of the Ag/AgI thin-film structure. We found that the roughness of the silver film increases fivefold as silvering times increase from 5 to 80 min. This increased surface roughness produces a concomitant linear increase in the attenuation coefficient for the silver-only guides for wavelengths shorter than approximately 5 microm.

Randomized prospective trial of early versus delayed feeding after percutaneous endoscopic gastrostomy placement

OBJECTIVE

By convention, most clinicians delay feeding through the gastrostomy tube until 24 h after placement. However, evidence is lacking to support the rationale for such a delay in PEG use. This randomized, prospective study was designed to assess the safety of early feeding after PEG placement.

METHODS

One hundred-twelve patients referred for PEG were randomized to begin tube feedings at 4 h (group A) or at 24 h (group B) after placement. All patients received prophylactic antibiotics. Full-strength Isocal was administered with the following schedule: day 1, 100 ml every 4 h for six feedings; day 2, 200 ml every 4 h for six feedings. Immediately before each scheduled feeding, gastric residual volume was recorded and the next feeding was withheld if the residual volume was > 50 percent (gastric retention). Patients were evaluated on day 1, day 2, day 7, and day 30 for major and minor complications.

RESULTS

The two groups were similar with regard to age, gender, baseline nutritional status, and indications for PEG placement. On the first day of feeding, 14 of 57 patients (25%) in group A, but only five of 55 patients (9%) in group B, had evidence of gastric retention, p = 0.029. The proportion of patients with high gastric residual volumes was not significantly different on day two. In group B, one death occurred because of aspiration of gastric contents on day 2. All other complications were minor and did not differ significantly between the two groups.

CONCLUSIONS

Early initiation of PEG feedings is safe, well tolerated, and reduces cost by decreasing hospital stay.

Eugene W. Caldwell Lecture. Technology: the key to controlling health care costs in the future

The American health care financing system is in a state of crisis. The rising cost of health care and the progressive difficulty Americans are experiencing in accessing the system have produced a great national debate concerning the future of medicine in America. Current health care cost trends, which are not sustainable, are projected to consume 37% of the gross national product by the year 2030. The financing system that supports the health care system is failing. The number of uninsured residents is growing more than twice as fast as the number with health insurance. The legitimate concern about the spiraling cost for medicine has focused attention on seeking root causes. Critics have focused on technology as the single most important factor in driving the cost trends in medicine upward. They have concluded that "long-term control of the rate of increase in expenditures requires that we curb the development and diffusion of clinically useful technology." These critics have not made their case, because they base their conclusions on hospital-derived data. These data are inaccurate because of the phenomenon of "cost-shifting." The critics do not examine the important issue of productivity and do not have reliable data on the costs and benefits of new technologies. Finally, the critics do not take into account the issue of use and abuse of technology. This is particularly important in the ambulatory environment. To break the health care cost spiral, radiologists, as the keepers of new technology, must commit themselves to at least four fundamental initiatives. The current American hospital-based health system must be replaced with an ambulatory system; productivity must be the primary business goal for radiologists; pricing of new services should reflect actual resources consumed, not the in-patient services displaced; and radiologists must reassert their role as doctors' doctors. The health care cost spiral is a real national crisis. The mission for radiology is to introduce the minimally invasive, ambulatory system of the future. The costs for delivering care within the new system will be a fraction of former costs. My assignment is to present a perspective on the role radiology must play in introducing new imaging technology to medicine. One of the distinguishing features of American society is its fascination with technology. It is only natural that the American health care system reflects this orientation.

Effects of mycorrhizae, phosphorus availability, and plant density on yield relationships among competing tallgrass prairie grasses

A replacement series experiment was used to investigate the effects of mycorrhizae, phosphorus availability, and plant density on competitive relationships between three tallgrass prairie species of varying mycorrhizal dependencies. Under mycorrhizal conditions, the obligately mycorrhizal dependent warm-season grass Andropogon gerardii (big bluestem) was a better competitor in mixture with the nonmycorrhiza-dependent cool-season grass Koeleria pyramidata (Junegrass). In the absence of mycorrhizae, however, competitive effects of big bluestem were greatly reduced and Junegrass experienced competitive release. Relative yield totals increased when mycorrhizae were suppressed, suggesting greater intensity of interspecific competition in the presence of mycorrhizae. Thus, the competitive dominance of big bluestem in tallgrass prairie is strongly related to its mycorrhizal status. Elymus canadensis (Canada wild rye) outcompeted big bluestem both with and without mycorrhizae. Relative yield totals of this species mixture were also lower under mycorrhizal conditions, indicating that mycorrhizae increase the intensity of interspecific competition between them. Relative yields of wild rye competing with big bluestem increased in the absence of mycorrhizae, suggesting that it also experiences competitive release when big blue-stem are not mycorrhizal. The outcomes of competition were generally similar among the three total plant density treatments and between P-fertilized and nonfertilized treatments. However, interactions between mycorrhizal effects and plant density confirm that outcomes of interspecific competitive interactions may be density dependent in some cases. Key words: arbuscular mycorrhizae, de Wit replacement series, Andropogon gerardii, Elymus canadensis, Koeleria pyramidata.

Similarity of dynamic range adjustment in auditory nerve and cochlear nuclei

Rate versus level functions were recorded for responses to best-frequency (BF) tones of 116 cochlear nucleus units and 53 auditory-nerve fibers in the presence of interrupted tone backgrounds and continuous noise backgrounds of various intensities. The backgrounds shifted the dynamic ranges of rate-level functions to higher test intensities, so in the presence of backgrounds, rate saturation occurred at higher intensities than in quiet. The shift in saturation intensity evoked by each background was measured by comparing the rate-level function recorded with the background to one recorded without. The relation between change in saturation intensity and background intensity could be approximated by the formula (formula: see text) delta Isat is the shift in saturation intensity, I is the background intensity, theta is the threshold for evoking shift, and A is the ratio of shift to background intensity re theta. In the appendix, it is shown that A is a measure of a unit's ability to avoid saturation by the background stimulus. The optimal value of A is unity, at which point a unit's operating range is infinite. The value of A depended on BF for interrupted tone backgrounds, but not for continuous noise backgrounds. For BF less than 10 kHz, the mean value of A for tone backgrounds was 0.33 in the auditory nerve, 0.37 in the ventral cochlear nuclei (VCN), and 0.47 in the dorsal cochlear nucleus (DCN). The difference between auditory nerve and VCN was not statistically significant. For BF greater than 10 kHz, the mean A was 0.16 in auditory nerve and 0.30 in VCN. The mean value of A for noise backgrounds was 0.79 in auditory nerve, 0.86 in VCN, 0.86 in DCN units of response types II and III, and 1.04 in DCN type IV units. Only the differences between DCN type IV and the non-DCN unit groups were statistically significant. The qualitative changes produced in rate-level functions by tone and noise backgrounds were similar in auditory nerve and cochlear nuclei except for DCN type IV units. The shifts in rate functions produced by interrupted tone backgrounds did not prevent saturation of the rate response at background intensities above the dynamic range of the unit as recorded in quiet. However, the rate response to test tones was preserved in the presence of all noise background levels used (up to a 30-dB spectrum level). The shift in rate function produced by the noise was almost sufficient to allow the unit to encode test intensity relative to noise background intensity.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of continuous noise backgrounds on rate response of auditory nerve fibers in cat

This study describes the effects of broadband background noise on the average discharge rate to best-frequency (BF) tones of auditory nerve fibers in the cat. The effects of exposure to long-term continuous noise are compared to the effects of noise gated on and off simultaneously with test tones. Addition of background noise causes a shift of the dynamic portion of tone-evoked rate versus level functions to higher tone intensities. The shift occurs at a mean rate of 0.61 dB of shift for each 1-dB increment in noise level. The rate of shift is independent of best frequency and spontaneous discharge rate. The noise level at which the shift begins is frequency dependent and is consistent with the frequency-dependent bandwidths of auditory nerve fiber tuning curves. The adjustment of the dynamic range shows many similarities to two-tone suppression. Therefore, it is most likely that it is caused by suppression of the response to the BF test tone by energy present in the noise at surrounding frequencies. At high noise levels, the ability of auditory nerve fibers to respond to test tones is limited by the rate response to the noise. As noise level increases, the discharge rate it evokes approaches a fiber's saturation rate and ultimately eliminates the fiber's ability to respond to test tones. Low spontaneous rate fibers, which have been shown to have higher thresholds and wider dynamic range (17,29), are significantly more resistant to saturation by high noise levels. Exposure to broadband noise prior to onset of test tones produces an overall decrement in response rate. This phenomenon is similar to the effects of short-term adaptation (32) and seems to develop independently of the shift of dynamic range. At high noise levels, previous exposure to the noise produces a small dynamic range shift. This effect is similar to that produced by suppression but is smaller. The effect is occluded in continuous noise backgrounds by the adjustment of sensitivity produced by suppression.

Interaural crosstalk in the cat

The physiologically effective interaural acoustic crosstalk in cat was measured by means of binaural threshold differences for single auditory-nerve fibers and for cochlear microphonics. There were generally two maxima, at about 800 Hz and 3 kHz, attaining values as high as -25 dB (transmission to cochlea via contralateral ear re transmission via ipsilateral ear) in some cats. This figure could be reduced to -50 dB by mechanically isolating the acoustic drivers from each other and from the stereotaxic head frame.

Hereditary C2 Deficiency: HLA Gene Complex Associations with Recombinant Events

Ten families with genetically determined C2 deficiency have been studied for HLA gene complex associations. Nine of the propositi were heterozygous and one homozygous for the deficiency; all 10 also had rheumatic disease. C2 deficiency was found to be associated with the HLA-A10,B18 haplotype in seven families and with A2,B18; AW25,B18; and A10,BW40 haplotypes in the other three. Mixed lymphocyte culture (MLC) was used to define the HLA-D locus (MLC, mixed leukocyte reaction (MLR)) among C2-deficient individuals in order to obtain additional information as to the localization of the C2 gene on the HLA chromosome. A sibling pair, identical for the HLA-A and B loci, with the C2 heterozygous-deficient state linked to the A10,B18 haplotype in both, were mutually non-responsive in mixed lymphocyte cultures. Another sibling pair also identical for the A and B loci were, by contrast, mutually stimulatory in MLC. One sibling is C2 heterozygous deficient and the other is C2 normal.

Hereditary C2 deficiency: diagnosis and HLA gene complex associations

Nine families with genetically controlled C2 deficiency have been described where the propositii and family members are heterozygous C2 deficient. The diagnosis of hereditary C2 heterozygous deficiency was suspected on the basis of analysis for CH50, C2 protein, and C2 function, and then confirmed by family studies. Analysis of HLA antigens in these families supported the close association of C2 defiency and HLA-A10 and/or B18, particularly the latter. Analysis by MLC studies revealed recombination in one family between the HLA and B and D loci and in another family probable recombination between the D and C2 complement loci. Therefore, the order of the loci on the sixth chromosome is likely to be C2 complement, HLA-D, HLA-B, HLA-A.

Re-examination of histocompatibility antigens found in patients with juvenile rheumatoid arthritis

One hundred and twenty-three patients with juvenile rheumatoid arthritis and a similar number of controls were tissue typed for 30 HL-A antigens to determine if there were any associations between particular HL-A antigens and the disease. None were found. However, HL-A7 was found more frequently in patients with juvenile rheumatoid arthritis demonstrating tenosynovitis than in the population with juvenile rheumatoid arthritis as a whole. These observations fail to support the contention of others that HL-A-W27 is found more frequently than expected in such patients.