Scaling perceived saturation.

Two psychophysical experiments were conducted at North Carolina State University (NCSU) and Rochester Institute of Technology (RIT) to obtain replicated perceived saturation data from color normal observers on the order of one unit of saturation. The same 37 Munsell sample sheets, including up to four references that had similar perceived saturation but different hue, were used in both experiments. Different assessment methods included presenting either four references simultaneously or only one reference at a time to observers and obtaining judged saturation magnitudes for the given Munsell samples. Four saturation models comprising Sab*, Suv*, CIECAM02, as well as Richter/Lübbe, were tested. CIECAM02 gave the best prediction of saturation for data obtained at NCSU while Sab* outperformed other models for the RIT data. For the combined dataset, Sab*, the Richter/Lübbe, and CIECAM02-based saturation models exhibited comparable performances. The Standardized Residual Sum of Squares index was used to measure the inter- and intra-observer variability and goodness of fit. Inter- and intra-observer variability of assessments was smaller than or comparable to those reported for the typical color difference evaluation experiments.

Neuromuscular stimulation therapy after incomplete spinal cord injury promotes recovery of interlimb coordination during locomotion.

The mechanisms underlying the effects of neuromuscular electrical stimulation (NMES) induced repetitive limb movement therapy after incomplete spinal cord injury (iSCI) are unknown. This study establishes the capability of using therapeutic NMES in rodents with iSCI and evaluates its ability to promote recovery of interlimb control during locomotion. Ten adult female Long Evans rats received thoracic spinal contusion injuries (T9; 156 +/- 9.52 Kdyne). 7 days post-recovery, 6/10 animals received NMES therapy for 15 min/day for 5 days, via electrodes implanted bilaterally into hip flexors and extensors. Six intact animals served as controls. Motor function was evaluated using the BBB locomotor scale for the first 6 days and on 14th day post-injury. 3D kinematic analysis of treadmill walking was performed on day 14 post-injury. Rodents receiving NMES therapy exhibited improved interlimb coordination in control of the hip joint, which was the specific NMES target. Symmetry indices improved significantly in the therapy group. Additionally, injured rodents receiving therapy more consistently displayed a high percentage of 1:1 coordinated steps, and more consistently achieved proper hindlimb touchdown timing. These results suggest that NMES techniques could provide an effective therapeutic tool for neuromotor treatment following iSCI.

CYP2D6 genetic variation in healthy adults and psychiatric African-American subjects: implications for clinical practice and genetic testing.

Limited information is available on the frequency of the many CYP2D6 alleles found in African-Americans. DNA was isolated and genetic testing was performed on samples from 222 African-Americans, healthy controls (n=131), and psychiatric patients (n=91). Each DNA was tested for CYP2D6 alleles *2, *3, *4, *5, *6, *7, *8, *9, *10, *11, *14, *15, *17, *18, *19, *20, *25, *26, *29, *30, *31, *35, *36, *37, *40, *41 and *43 and 8 multiple copy alleles (*1xn, *2xn, *4xn, *41xn, *2Lxn, *17xn, *35xn and *10xn) using the AmpliChip CYP450 prototype microarray assay, along with allele-specific-PCR and PCR restriction fragment length polymorphism methods. No significant difference was noted between controls and psychiatric patients in any CYP2D6 allele frequencies. Three subjects were genotyped as poor metabolizers (1.4%; 0.0-2.9%, 95% confidence intervals (CI)), and 10 were classified as ultrarapid metabolizers (4.5%; 1.8-7.2%, 95% CI). A new CYP2D6 allele (*58) and two new duplicated CYP2D6 alleles (*17xn and *2Lxn) not previously reported were also identified. The frequency of the CYP2D6 overexpression in African-Americans may represent a greater therapeutic challenge than its deficiency based on these results. The most common alleles found in African-Americans including CYP2D6*1, *17 and *41 need to be investigated more closely for race-specific allelic variations and the mechanism responsible for differences in allele function more closely examined. The diversity of CYP2D6 alleles suggests that nucleotide arrays or similar methods are needed to efficiently test for the most prominent/relevant CYP2D6 alleles in humans.

Association between CYP2D6 genotype and tardive dyskinesia in Korean schizophrenics.

The CYP2D6 gene codes for human cytochrome P450 2D6 enzyme, which is responsible for the metabolism of many psychiatric drugs. In schizophrenic patients treated with neuroleptics, decreased or loss of function CYP2D6 alleles may contribute to the development of tardive dyskinesia (TD), a movement disorder that frequently occurs with chronic neuroleptic treatment. The goal of this study was to determine whether the occurrence of TD is associated with CYP2D6 genotype in a cohort of Korean schizophrenics by employing a CYP450 GeneChip((R)) oligonucleotide microarray and PCR assays to screen for 19 CYP2D6 alleles. Our results revealed that males with at least one decreased or loss of function allele have a moderately greater chance of developing TD than males with only wild-type alleles. Female schizophrenics did not have a significantly greater chance of developing TD. Our results demonstrate the utility of CYP2D6 microarrays to assess genotype status in this Korean cohort.

Prevalence of adult domestic violence among women seeking routine care in a Native American health care facility.

OBJECTIVES: The purpose of this study was to determine the prevalence of, and sociodemographic factors associated with, adult domestic violence within a Native American community. METHODS: Adult women in the community were surveyed. RESULTS: Of 371 eligible women, 341 (92%) were surveyed. Among respondents, 179 reported a history of at least 1 episode of domestic violence. Fifty-six (16.4%) reported violence within the previous 12 months. Age under 40 years and living in a household receiving governmental financial assistance were independently associated with 1-year prevalence of adult domestic violence. CONCLUSIONS: Adult domestic violence is prevalent within this Native American community. Additional research is required to characterize further the relationship between domestic violence and socioeconomic status.

Psychophysical evaluation of gamut mapping techniques using simple rendered images and artificial gamut boundaries.

Using a paired comparison paradigm, various gamut mapping algorithms were evaluated using simple rendered images and artificial gamut boundaries. The test images consisted of simple rendered spheres floating in front of a gray background. Using CIELAB as our device-independent color space, cut-off values for lightness and chroma, based on the statistics of the images, were chosen to reduce the gamuts for the test images. The gamut mapping algorithms consisted of combinations of clipping and mapping the original gamut in linear piecewise segments. Complete color space compression in RGB and CIELAB was also tested. Each of the colored originals (R,G,B,C,M,Y, and Skin) were mapped separately in lightness and chroma. In addition, each algorithm was implemented with saturation (C(*)/L(*)) allowed to vary or retain the same values as in the original image. Pairs of test images with reduced color gamuts were presented to twenty subjects along with the original image. For each pair the subjects chose the test image that better reproduced the original. Rank orders and interval scales of algorithm performance with confidence limits were then derived. Clipping all out-of-gamut colors was the best method for mapping chroma. For lightness mapping at low lightness levels and high lightness levels particular gamut mapping algorithms consistently produced images chosen as most like the original. The choice of device-independent color space may also influence which gamut mapping algorithms are best.

Time course of chromatic adaptation for color-appearance judgments.

Observer production of achromatic appearance has previously been used to measure the time course of chromatic adaptation for changes from daylight to incandescent illuminants at constant luminance, indicating an exponential decay of chromatic adaptation with a time constant of the order of 10 s. The work extends previous results in several ways. The psychophysical technique was significantly improved to provide more reliable estimates of color appearance as a function of adaptation duration, and the time course of chromatic adaptation was measured for six chromaticity changes. Three observers tracked achromatic appearance on a computer-controlled CRT display during transitions of 2-min duration between the various chromaticities. The results indicate that observer differences are statistically significant. However, differences in time course for different chromaticity changes are not statistically significant (within observer). Single or piecewise exponential decay functions cannot be fitted to the data. However, sum-of-two-exponentials functions provided accurate descriptions of the data. The results suggest two stages of adaptation: one extremely rapid (a few seconds) and the other somewhat slower (approximately 1 min). Chromatic adaptation at constant luminance was 90% complete after approximately 60 s.

Continuous quality improvement in inpatient clinical nutrition services.

Defining quality patient care is a complex and often confusing issue. This article describes one hospital's experience in applying quality improvement theories to inpatient clinical nutrition practice. The key to measuring quality was the use of standardized practice guidelines. In this article, terms such as continuous quality improvement are clarified and fundamental assumptions such as "quality is defined as conformance to requirements" are discussed. We review a working model for the 10-step plan of the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) and its application in practice, including the indicators and measurement tools used. Actual results from ongoing quality improvement efforts are addressed and compared to the JCAHO nine components of quality patient care. Because of preexisting nutrition practice guidelines at the Yale-New Haven Hospital, improvements in the delivery of patient nutrition care could be demonstrated; these included enhanced efficiencies in screening and intervention. Continuous quality improvement initiatives do work, and practitioners can use the practice experience presented here as a conceptual framework to justify or validate the quality of patient nutrition care in their own institutions.

Ganglion cell pathways for rod vision.

Measurements of the acuity of rod vision made by two different techniques show it to vary only slightly with eccentricity. At eccentricities beyond 15 deg acuity is well predicted from the sampling properties of the mosaic of the P-class of ganglion cells. With decreasing eccentricity acuity falls progressively below the sampling limit of P-cells, but even at the lowest eccentricity examined (5 deg) does not reach the limit imposed by the sampling properties of the mosaic of M-cells. At an eccentricity of 5 deg rod vision could be supported by as few as 20% of P-cells.

Sleep-wake disturbances in an animal model of chronic cholinergic insufficiency.

Rats reared on a diet in which choline is replaced with N-aminodeanol (NADE), undergo > 50% replacement of brain acetylcholine with acetylated NADE, a false cholinergic transmitter. We examined amounts of sleep and wakefulness in 7 littermate pairs of rats fed either NADE-substituted, or a choline control diet for > 100 days after weaning. During the lights-on portion of the 12/12 h light/dark cycle, NADE rats spent more time awake, and less time in both non-REM and REM sleep compared to littermate controls. Average durations of waking episodes were significantly increased in NADE rats. During the 12 h dark period, there were no between-group differences in sleep-waking amounts. Behavioral hyper-responsiveness which interferes with sleep onset, combined with reduced activity in brainstem cholinergic mechanisms involved in REM sleep generation may underlie daytime sleep-waking disturbances in NADE rats.

Cholinergic mechanisms in startle and prepulse inhibition: effects of the false cholinergic precursor N-aminodeanol.

We examined the effects of cholinergic deficiency on prepulse inhibition (PPI) of the acoustic startle. Rats treated with a choline-free diet that contained the false cholinergic precursor N-aminodeanol showed great deficit in PPI. This deficit does not appear to be secondary to an increase of stereotyped behaviors. Startle threshold was also greatly reduced, as these rats startled to the 70-dB prepulse and the baseline startle amplitude was increased by 60% over the control rats. Arecoline (4 mg/kg) partially reversed the deficit in PPI. This improvement persisted beyond the period of drug treatment. On the other hand, scopolamine (1 mg/kg) reduced PPI in the control rats. These results suggest that cholinergic systems play a major role in both the elicitation and prepulse inhibition of startle.

Chromatic adaptation to natural and incandescent illuminants.

A color CRT image display system was used to present adapting backgrounds that were spatially and temporally varied. Three observers adjusted the chromaticity of test stimuli to produce an achromatic appearance under a variety of adapting conditions. The achromatic-appearing chromaticities were used as measures of the observers' states of chromatic adaptation. The spatial configuration of the adapting background was varied to measure the spatial extent of the mechanisms responsible for chromatic adaptation. The temporal configuration of the adapting background was varied to measure the time-course of these mechanisms. The results show that chromatic adaptation is spatially localized with a time-course on the order of 10 sec. Since the mechanisms were shown to be spatially localized, the observed temporal integration across eye movements is required to allow these mechanisms to adjust to the spatially integrated scene chromaticity.

Protective effects of felbamate against hypoxia in the rat hippocampal slice.

BACKGROUND AND PURPOSE: Felbamate is a new dicarbamate anticonvulsant with low toxicity currently being investigated in human clinical epilepsy trials. In this study, we examined the protective effects of felbamate against hypoxia. METHODS: We exposed paired rat hippocampal slices to hypoxia with and without felbamate treatment while monitoring the CA1-evoked population spike. RESULTS: Felbamate provided dose-dependent neuroprotection against hypoxia at concentrations of 45 mg/l and greater (p less than 0.05). At a felbamate concentration of 300 mg/l, recovery of CA1 evoked population spike amplitude after hypoxic exposure was 99% compared with 0.5% for unmedicated paired slices. The appearance and disappearance of the hypoxic injury potential was delayed in slices treated with 300 and 400 mg/l (p less than 0.05). CONCLUSIONS: In this model of hypoxia, felbamate provided neuroprotection against hypoxia at concentrations similar to serum felbamate levels currently being used in human clinical epilepsy trials.

Managing inpatient clinical nutrition services: a comprehensive program assures accountability and success.

A major challenge facing clinical dietitians today is justifying inpatient clinical nutrition services. To meet this challenge, a comprehensive program for the delivery and management of clinical nutrition services was developed at Yale-New Haven Hospital. It is based on seven nutritional risk factors--age, diagnosis/treatment, diet, metabolic or mechanical problems, significant lab values, pertinent medications, and weight for height. These risk factors are used to categorize patients into one of seven classifications. In essence, this classification system is the screening tool used to provide the foundation for standards of practice and nutrition assessment and intervention. The inherent advantage of such a program is that it identifies patients at high nutritional risk, regardless of wide variations in patient population or diagnosis. It also provides standardized criteria for evaluating quality of care, patient acuity, and productivity and staffing. Clinical nutrition services can then be measured for both quality and quantity. Because protein-calorie malnutrition poses a serious threat to cost containment and quality patient care, this type of program can appeal to hospital administrators, physicians, and site visitors alike. It can serve as an adaptable model for the delivery and management of inpatient clinical nutrition services in a wide variety of health care facilities.