Human cone spectral sensitivities: a progress report

The spectral sensitivities of the short (S-), middle (M-) and long (L-) wave-sensitive cones have been measured in normal trichromats and in dichromats and monochromats of known genotype. For the S-cone sensitivities, three blue-cone monochromats and five normals were used; for the M-cone sensitivities, nine protanopes (three with a single L1M2 gene, three with a single L2M3 gene, one with both an L1M2 and an M gene, and two with both an L2M3 and an M gene); and for the L-cone sensitivities, 22 deuteranopes (five with a single L(ala180) gene and 17 with a single L(ser180) gene). We compare existing cone spectral sensitivity estimates with these results and with tritanopic color matches. The new findings are more consistent with the cone fundamentals of Stockman et al. (JOSA 1993(A10), 2491) than with those of Smith and Pokorny (Vision Research 1975(15), 161). The discrepancies that we find, however, are sufficient to warrant the replacement of both sets.     

Behavioral spectral sensitivities of different retinal areas in pigeons.

The spectral sensitivity of the red and the yellow retinal fields of head-fixed pigeons was separately measured for wavelengths between 340 and 640 nm by a behavioral perimetric technique. Within this spectral range the mean spectral sensitivity of both fields was found to be maximal at 584 nm and minimal at the lower ultraviolet wavelengths. Differences in sensitivity were found, however, at shorter wavelengths, with the yellow field being more sensitive than the red at wavelengths below 500 nm and especially in the ultraviolet spectral range. These sensitivity differences are discussed in relation to other functional differences between the pigeon's retinal fields. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tendon force measurements and movement control: a review

Knowledge of the mechanical and electrical output from skeletal muscle is of interest to investigators from several disciplines including physiology, biomechanics, neuroscience, orthopedics, and physical rehabilitation. Estimates of muscle output (i.e., force) have generally been made using indirect calculations. Forward solution (e.g., EMG) and optimization models have recently been developed using a wide variety of input parameters to estimate force output of individual muscles. These estimates, however, have lacked comparison values necessary for validation. In vivo measurements of muscle force have been made in both animals and humans using a "buckle" type tendon transducer surgically implanted on the tendons of the muscles under study. Investigations utilizing these transducers have addressed a wide range of questions regarding muscle function. This review examines the use of this technology and discusses the significance of the future use of "buckle" transducers in studies exploring load sharing among muscles and in the validation of existing models that estimate muscle force.     

Reproducibility of in vivo carotid intima-media thickness measurements: a review

The gyrA gene of Campylobacter fetus subsp. fetus, which encodes the A subunit of DNA gyrase, was cloned, and its nucleotide sequence was determined. An open reading frame of 2,586 nucleotides which encodes a polypeptide of 862 amino acids with an Mr of 96,782 was identified. C. fetus subsp. fetus GyrA is most closely related to Campylobacter jejuni GyrA, with 73% homology at the nucleotide level and 78% identity between polypeptides. The next most closely related GyrA was that from Helicobacter pylori, with both DNA homology and amino acid identity of 63%. The gyrA and gyrB (DNA gyrase B subunit) genes were located on the genomic map of C. fetus subsp. fetus ATCC 27374 and shown to be separate. A clinical isolate of C. fetus subsp. fetus and a laboratory-derived mutant of ATCC 27374, both resistant to ciprofloxacin, had identical mutations within the quinolone resistance determining region. In both mutants a G-->T transversion, corresponding to a substitution of Asp-91 to Tyr in GyrA, was linked to ciprofloxacin resistance, giving MICs of 8 to 16 micrograms/ml.     

On derivation of spectral sensitivities of the human cones from trichromatic colour matching functions

Despite the recent advance made by using the direct methods of retinal densitometry, microspectrophotometry and suction electrophysiology, the psychophysical approach based on colour matching data still remains an important source of accurate information about the spectral sensitivity of the cone photoreceptors in the human visual system. However, the commonly used technique of estimating cone sensitivities, based on the assumption that dichromacy is caused by the lack of one of the three types of the cone photoreceptors, requires the colour matching functions not only from trichromatic observers but from dichromats as well. Here we evaluate an alternative approach, originally put forward by Bongard and Smimov, that derives cone spectral sensitivities from colour matching functions only; without resorting to colour deficiency or any other data. When applied to CIE standard colour matching functions, this method yields curves of spectral sensitivities that are close to the classical Smith-Pokorny fundamentals, though the long-wave cone is shifted towards the short-wave region of the spectrum by 5 nm, as compared with Smith and Pokorny's results.     

EEG spectral topography in neurology: I. A review of techniques

As researchers investigate methods of automated interpretation of the electroencephalogram (EEG), spectral topography is emerging as an important and popular technique in applied clinical neurophysiology. Several computer-based EEG topography systems have been developed to produce topographic maps showing the spatial distributions of pre-defined frequency bands in the EEG. However, there is ongoing debate as to which technical approaches to EEG topography generate maps that can be most accurately interpreted by clinicians. This paper reviews existing topographic techniques, particularly as they apply to diagnostic neurology, and discusses some of the technical choices that must be addressed by topography users. These choices include the selection of montage, epoch length, interpolation scheme, graphical display method, and artifact removal technique. The points summarised here highlight the general opinion that although EEG topography has many benefits, it should be invoked with care and the user should possess an indepth understanding of the procedures used to produce the topographic maps.     

Arizona hinshawii infections. New cases, antimicrobial sensitivities, and literature review

In order to objectively document the accepted clinical efficacy of ampicillin in treating bacterial exacerbations of chronic bronchitis, as well as to evaluate the efficacy of methacycline, a double-blind crossover study was designed. Twenty patients with chronic bronchial disease were treated for two separate acute bacterial exacerbations, once with 2 gm of ampicillin daily, and once with 600 mg of methacycline daily, for 14 days. There were a few significant differences when comparing the efficacy of the antimicrobials. For example, the daily volume of sputum significantly went from 35.6 ml initially to 20.5 ml at the end of treatment with methacycline, and from 37.4 to 18.0 ml with ampicillin. Sputum neutrophils excreted per day went from 446 to 147 million with methacycline and from 433 to 94 million with ampicillin. Gram-positive diplococci and cocci on gram stains of sputum significantly decreased form 10.6 to 3.3 with methacycline and from 16.8 to 2.1 with ampicillin. This investigation objectively documents with accepted clinical efficacy of ampicillin and proves methacycline to be an equally effective agent.     

Automated spectral analysis I: formation of a priori information by spectral simulation

A spectral simulation method is described for generating a priori information for use in parametric spectral analysis. The method makes use of GAMMA (S. A. Smith, T. O. Levante, B. H. Meier, R. R. Ernst, J. Magn. Reson., 106A, 75-105, 1994), a programming environment that facilitates simulation of magnetic resonance phenomena. The input parameters consist of the chemical shifts and scalar spin-coupling constants for the compounds to be analyzed, the acquisition pulse sequence, and the field strength used. The resultant spectral information consists of the relative amplitude, frequency, and phase of all resonances, which are stored in a spectral database. This procedure can be rapidly and conveniently modified to reflect different acquisition parameters and data analysis requirements.     

Red, green, and red-green hybrid pigments in the human retina: correlations between deduced protein sequences and psychophysically measured spectral sensitivities

To analyze the human red, green, and red-green hybrid cone pigments in vivo, we studied 41 male dichromats, each of whose X chromosome carries only a single visual pigment gene (single-gene dichromats). This simplified arrangement avoids the difficulties of complex opsin gene arrays and overlapping cone spectral sensitivities present in trichromats and of multiple genes encoding identical or nearly identical cone pigments in many dichromats. It thus allows for a straightforward correlation between each observer's spectral sensitivity measured at the cornea and the amino acid sequence of his visual pigment. For each of the 41 single-gene dichromats we determined the amino acid sequences of the X-linked cone pigment as deduced from its gene sequence. To correlate these sequences with spectral sensitivities in vivo, we determined the Rayleigh matches to different red/green ratios for 29 single-gene dichromats and measured psychophysically the spectral sensitivity of the remaining green (middle wavelength) or red (long wavelength) cones in 37 single-gene dichromats. Cone spectral sensitivity maxima obtained from subjects with identical visual pigment amino acid sequences show up to a approximately 3 nm variation from subject to subject, presumably because of a combination of inexact (or no) corrections for variation in preretinal absorption, variation in photopigment optical density, optical effects within the photoreceptor, and measurement error. This variation implies that spectral sensitivities must be averaged over multiple subjects with the same genotype to obtain representative values for a given pigment. The principal results of this study are that (1) approximately 54% of the single-gene protanopes (and approximately 19% of all protanopes) possess any one of several 5'red-3'green hybrid genes that encode anomalous pigments and that would be predicted to produce protanomaly if present in anomalous trichromats; (2) the alanine/serine polymorphism at position 180 in the red pigment gene produces a spectral shift of approximately 2.7 nm; (3) for each exon the set of amino acids normally associated with the red pigment produces spectral shifts to longer wavelengths, and the set of amino acids normally associated with the green pigment produces spectral shifts to shorter wavelengths; and (4) changes in exons 2, 3, 4, and 5 from green to red are associated with average spectral shifts to long wavelengths of approximately 1 nm (range, -0.5 to 2.5 nm), approximately 3.3 nm (range, -0.5 to 7 nm), approximately 2.8 nm (range, -0.5 to 6 nm), and approximately 24.9 nm (range, 22.2-27.6 nm).     

Lumbar spinal stenosis: a review of current concepts in evaluation, management, and outcome measurements

The purpose of this review is to present current information from the literature regarding the pathoanatomy, clinical presentation, differential diagnosis, treatment, and outcome assessment methods for patients with lumbar spinal stenosis. Lumbar spinal stenosis is a frequently encountered condition, particularly in the elderly. Treatment requires an accurate diagnosis, but differential diagnosis of lumbar stenosis can be difficult. The literature to date has focused primarily on surgical treatment. The long-term efficacy of surgery has been questioned, and surgical procedures are associated with increased costs and risks of morbidity in an elderly population. A trial of conservative care is recommended in most cases, but there are presently no randomized controlled studies in the literature comparing surgical versus conservative management, or evaluating the effectiveness of any specific conservative treatment approach. The existing literature has further been criticized for having poorly defined outcome measures. The assessment of treatment outcomes should be multifactorial, including measures of pathoanatomy and impairments, as well as patient-centered measures such as level of disability, patient expectations, and satisfaction. The present level of understanding of lumbar spinal stenosis is deficient in many areas, including differential diagnosis, treatment, and outcome assessment. Future research should address these deficits to improve the management of patients with this condition.     

Local mobility within villin 14T probed via heteronuclear relaxation measurements and a reduced spectral density mapping

Villin 14T, a representative domain from the actin severing and bundling protein villin, binds calcium ions and actin monomers. To begin to understand the contributions of mobility to the villin-calcium and villin-actin interactions, relaxation rates for magnetization involving the amide nitrogens and protons have been measured for 15N-labeled villin 14T in solution. Although we have measured the complete set of rates required for a full spectral density map, difficulties in the accurate measurement of relaxation rates for antiphase coherence and two-spin order led us to consider a reduced mapping formalism. From the reduced spectral density map, a model-free analysis, or directly from the measured Nx,y relaxation rates, local variations in mobility along the backbone of villin 14T have been revealed. Fast motions are evident not only at the amino and carboxyl termini but also in the turn between strands beta 4 and beta 5 of the central beta-sheet and in the turn between helix alpha 3 and strand beta 7. Slower motions are suggested for the turn between strands beta 2 and beta 3. Motions on the microsecond to millisecond time scale have been probed directly by examining the dependence of the proton transverse relaxation rate on the spin-locking field strength. Leu11 shows a strong dependence on field strength, implying conformational exchange with a time constant of 125 +/- 69 microseconds. The backbone at the actin-binding interface appears to be rather rigid.     

Comparative sensitivities and specificities of the mass measurements of CK-MB2, CK-MB, and myoglobin for diagnosing acute myocardial infarction

We evaluated the clinical utility of the mass measurement of the tissue isoform of creatine kinase MB isoenzyme (CK-MB2) in the diagnosis of an acute myocardial infarction (AMI) by determining its sensitivity, specificity, and predictive value relative to those of CK-MB mass and myoglobin. Samples were obtained at 0, 4, 8, and 16 h postpresentation from 100 patients (41% with AMI). The order of sensitivity for the sample proportions taken at 0-2 h from the onset of symptoms was myoglobin > CK-MB2 > CK-MB. At all other time points, the sensitivity of CK-MB2 either equaled or surpassed that of both CK-MB and myoglobin, although the 95% confidence intervals for the population proportions each of these markers overlapped. Of the 41 AMI patients, 31 (76%) exhibited concurrent abnormal increases of CK-MB and %CK-MB2; the other 10 (24%; 8 non-Q wave, 2 Q wave) exhibited abnormal values for %CK-MB2 before their CK-MB exceeded the upper limit of normal. The specificity of myoglobin was statistically lower than that for either CK-MB2 or CK-MB at all time points.     

Myocarditis: a review

BACKGROUND AND OBJECTIVES: Although pediatric sedation (PS) is widely used in emergency departments (ED), the practice of PS in general community hospital (GH) ED has not been described. We surveyed PS practice patterns in pediatric hospitals (CH) and GH and compared frequency and usage between the two groups. METHODS: All CH (n = 115) and 400 randomly selected GH were surveyed. Alcohol and drug detoxification, psychiatric, chronic care, rehabilitation, and specialty facilities were excluded. Data were collected on hospital type (pediatric or community), location (urban, suburban, rural), annual visits, academic affiliation (presence of an emergency medicine residency or pediatric emergency medicine fellowship in the hospital), and sedation agents used. RESULTS: Of 515 hospitals surveyed, 238 responded [84/115 CH (73%), 154/400 GH (39%)] yielding an overall response rate of 46%. Of the responding CH the majority were urban [57 (68%) were urban, 15 (18%) suburban, and 12 (14%) rural]. GH were more evenly distributed by location [44/153 (29%) were urban, 49/153 (32%) suburban, and 60/153 (39%) rural]. Eight (5%) GH had emergency medicine residencies, while 39 (46%) CH had pediatric emergency medicine fellowships. The mean annual pediatric volume was 38,000 for CH and 6500 for GH. For the four specified clinical scenarios, representing the most common ED procedures using sedation (laceration repair, fracture reduction, radiologic imaging), GH performed significantly fewer sedations than CH when matched for pediatric volume. PS was less frequently used among rural GH compared to suburban (P < 0.01) and urban GH (P < 0.01). Midazolam was listed as the most frequently used drug in all three geographic locations for both CH and GH. CH listed fentanyl as a second agent, while GH preferred meperidine. Fentanyl and ketamine were listed as preferred agents only in CH. For cranial computerized tomography, chloral hydrate was listed as the drug of choice by both CH and GH. Both CH and GH listed "relief of pain and anxiety" as the first and "agitation control" as the second most common reason for using sedation. CH and GH listed "the risks outweigh the benefits" as the primary reason and "ED too busy/takes too much time" as the secondary reason for not using sedation. CONCLUSIONS: GH performed fewer sedations than did CH when matched for pediatric volume in all geographic locations and for the most common ED procedures using sedation. Since 1989, sedation patterns have shifted in CH to include the short-acting agents, while GH (with the exception of midazolam) continue to prefer the long-acting agents. Midazolam is now the most frequently used sedation agent for ED procedures in both CH and GH.     

Hysteroscopy: a review

3 chemicals were selected for mutagenicity testing from a priority list, based on production volume and available mutagenicity data. Propargyl alcohol (PA), 2-nitroaniline (2NA), and 5-methyl-1H-benzo-triazole (MBT) were selected for testing using the approach recommended in the Health Protection Branch Genotoxicity Guidelines. The battery of tests included the Salmonella/mammalian microsome mutation assay, the in vitro chromosomal aberration assay, and the bone-marrow micronucleus assay. The results indicate that 2 of the 3 chemicals, PA and 2NA, were clastogenic in vitro. Both PA and 2NA induced chromosomal aberrations in CHO cells in vitro with and without metabolic activation, while none induced reverse mutations detectable with the Salmonella/mammalian microsome assay. Because PA and 2NA were found to be in vitro clastogens, they also were tested in the mouse bone-marrow micronucleus assay. 2NA induced a small increase in micronuclei in males but not females. PA did not induce an increase in micronuclei.     

Teleradiology: a review

The Biographical Personality Interview (BPI) was applied to 179 subjects (158 psychiatric patients and 21 probands from the general population); 100 patients and 20 healthy controls served as a validation sample; the others had been interviewed during the training period or did not meet the inclusion criteria for the validation of the BPI. The acceptance of the interview was high, the inter-rater reliability of the ratings of premorbid personality structures ("types") varied between 0.81 and 0.88 per type. Concurrent validity of the typological constructs as assessed by means of the BPI was inferred from the intercorrelations of type scores and correlations of these scores with questionnaire data and proved to be adequate. Clinical validity of the assessment was indicated by statistically significant differences between diagnostic groups. Problems and further developments of the instrument and its application are discussed.     

Moxonidine: a review

Moxonidine is an imidazoline compound which acts on I1 imidazoline 'receptors' in the central nervous system to reduce blood pressure. This novel mechanism of action is claimed to lead to fewer adverse effects than the older centrally-acting agents such as clonidine. In this review we examine the drug's pharmacology, clinical pharmacokinetics, efficacy as an antihypertensive agent including comparative studies with pre-existing drugs, and adverse effect profile. With a growing number of effective antihypertensive agents already available to the clinician, it is not yet clear whether moxonidine represents a significant advance in hypertension management.