Ritanserin as adjunct to fluoxetine treatment of OCD patients with psychotic features.
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Adult↗
Biomedical subjects
M Bach
Publications and source records attributed to M Bach.
Anti-aliasing and dithering in the 'Freiburg Visual Acuity Test'.
Anti-aliasing is a technique for improving spatial resolution at the cost of luminance resolution. Dithering is a technique for improving luminance resolution at the cost of spatial resolution. These techniques are applied to the testing of visual function in the 'Freiburg Visual Acuity Test': by employing anti-aliasing, spatial resolution was improved. Thus, even the shape of small Landolt-Cs with oblique gaps is adequate, and visual acuities from 5/80 (0.06) up to 5/1.4 (3.6) can be tested at a distance of 5 m. By employing dithering, subthreshold contrast stimuli can be generated on a conventional display having standard 8-bit video resolution. Rapid acquisition of a semi-objective and reliable acuity estimate makes the 'Freiburg Visual Acuity Test' useful for subject screening in vision research, as well as for routine assessments in the ophthalmic practice.
Computer Terminals↗
Raster-scan cathode-ray tubes for vision research--limits of resolution in space, time and intensity, and some solutions.
Raster-based cathode-ray tubes (CRTs) are increasingly used for stimulus presentation. While very flexible, their design based on consumer electronics can limit their value in vision research. Here their limitations of resolution in time, space, intensity and wavelength are systematically compiled. Often, ingenious ideas can circumvent such limitations for specific experiments. Some ad-hoc solutions, as well as the more general techniques of dithering and anti-aliasing, are presented.
Artifacts↗
A note on luminance calibration of raster-scan cathode-ray tubes: temporal resolution, ripple, and accuracy.
Accurate luminance calibration is an important issue for stimuli in vision research. Raster-scan cathode-ray tubes present a rapidly scanning spot with a luminance of the order of 10,000 cd m-2 (the actual value depends on video timing and phosphor persistence). With little spatial integration this may result in overloading of the front stage of a photometer. More importantly, even if averaged over hundreds of milliseconds, the pulsed nature of the luminance signal will markedly reduce accuracy of the luminance measurement. A frame-synchronised photometer is described to increase measurement accuracy whilst still rapidly acquiring the result.
Computer Terminals↗
Elderly patients' problems with medication. An in-hospital and follow-up study.
OBJECTIVES: To examine medication problems during a stay in hospital and after discharge and to identify risk factors that contribute to poor compliance with medication a prospective observational study was carried out in an university-affiliated geriatric hospital and a patients' home. PATIENTS: One hundred and nineteen patients admitted from home to the geriatric hospital underwent a comprehensive geriatric assessment. They were also tested in opening and removing tablets from various common medicine containers. Drug prescriptions before, during and after the hospital stay were recorded. Medication use at home was observed by a member of a hospital-based home intervention team. The patients' reports of their drug therapy was compared with those by their family doctors. RESULTS: Of all tested patients 10.1% failed to open at least one container. This inability was associated with poor vision, impaired cognitive function and low manual dexterity. Compliance with prescribed medication was associated with cognitive function, ability to handle medication containers, number of prescribed drugs and recent changes in drug prescriptions. Of the patients only 39.5% had stable drug prescriptions during the 3-month study period. Doctor/patient agreement concerning drug therapy was low in all age groups. The agreement rate and patients' knowledge of their treatment was correlated with cognitive function and the number of prescribed drugs. CONCLUSION: Patients' ability to open and remove tablets from common commercial packages/containers should be tested routinely during a stay in hospital. Management of medication should be taught and supervised within the first few days after discharge from hospital.
Aged↗
Prospective value of self-report and performance-based tests of functional status for 18-month outcomes in elderly patients.
To determine predictors of death, nursing home placement and hospital admission, a prospective study was carried out in a university-affiliated geriatric hospital and a general practice. One hundred and thirty-five patients consecutively admitted from home to the geriatric hospital and discharged home again (site 1), and 144 patients, aged 70 years and over, of a general practice (site 2) were recruited for a comprehensive geriatric assessment program. At baseline, none was completely dependent on others, or severely demented. At follow-up after 18 months, 46 subjects (17%) had died, 20 subjects (7%) had been institutionalized, and 79 had been admitted to hospital (28%) in the interim. Univariate analysis demonstrated a significant association between Barthel Activities of Daily Living (ADL), Lawton-Brody Instrumental Activities of Daily Living (IADL), Mini-Mental State Examination (MMSE), Balance and Gait Evaluation, Timed "Up and Go", Timed Test of Money Counting. Grip-Strength and Williams Board Test, and death as well as nursing home placement. Barthel-ADL were significantly correlated with hospital admission. In a logistic regression analysis, Barthel-ADL were independent predictors for death; Barthel-ADL, Timed "Up and Go", Timed Test of Money Counting, and Williams Board Test were independent predictors for nursing home placement. No independent predictor was found for hospital admission. It is concluded that self-report and performance-based measures of functional capabilities are useful instruments to identify patients at risk for nursing home placement and death. Factors contributing to hospital admissions are other than those measured by the applied tests.
Aged↗
Pain sensitivity, alexithymia, and depression in patients with eating disorders: are they related?
A decreased sensitivity to painful stimuli and high scores for alexithymia and depression have been observed in patients with eating disorders. We investigated the relationship between these factors in 22 patients with anorexia nervosa, 18 patients with bulimia nervosa, and 32 healthy subjects. Alexithymia was assessed using the 20-item Toronto Alexithymia Scale and depression using the Beck Depression Inventory. Patients with bulimia exhibited significantly higher thresholds to mechanically induced pain than healthy subjects. Thresholds to thermally induced pain in patients with anorexia or bulimia were similar and significantly higher than in the healthy subjects. Alexithymia and depression scores were significantly higher in anorexic and bulimic patients than in the healthy subjects. Analyses of covariance revealed that the degree of alexithymia did not influence thresholds to thermally and mechanically induced pain, whereas the severity of depression affected to some extent the threshold to thermally induced pain.
Adult↗
The abutting grating illusion.
Two line gratings abutting each other with a phase shift of half a cycle elicit the perception of an illusory line running orthogonally between the two sets of grating lines. We found that rating strength increases with increasing number of lines, line length, and phase angle. In contrast, rating strength decreases with increasing spacing of lines, lateral misalignment, rotation of one grating relative to the other, and line width. There is a pronounced oblique effect at 45 deg when the orientation of the abutting gratings is changed from horizontal through diagonal to vertical. Findings are interpreted in terms of a neurophysiological model. We conclude that the end-stopped receptive fields activated by the grating lines are about 6 deg long and 2 deg wide. On the other hand, the "response fields" of the cells, integrating orthogonally across line ends, are assumed to be 5 deg long and less than 1 deg wide. The psychophysical data compare favorably with available neurophysiological data in Area V2 of the macaque suggesting that the perception of illusory contours in human observers may be based on cortical cell properties similar to those found in the monkey.
Animals↗
[The Freiburg Vision Test before and after cataract operation].
BACKGROUND: Especially in aged patients testing the visual acuity can be most time consuming. An automatic test could therefore be of great help. The recently introduced "Freiburg Visual Acuity Test' (FVT) using a forced-choice determination of Landolt orientation has proved a reliable method of automatic visual acuity testing in younger patients. PATIENTS: To learn about practicability and ease of this self-administered test, we tried this test in 87 patients (mean age 73) before and after cataract surgery. The Landolt ring was presented in 8 different positions on a monitor. A keyboard of 8 buttons, depicting the possible orientation of the Landolt C, allowed the patients to run through the test by themselves. With each patient's correct response, the size of the Landolt ring decreased accordingly. RESULTS: Although near vision of all patients was grossly impaired and accommodation power zero, handling of the keyboard for the subject's response was generally reported as easy. The reliability and reproducibility of the obtained values were good and close to acuity values obtained using projected test figures according to DIN. Prior to cataract surgery we found DIN values statistically significantly lower than FVT values. This difference did not persist after surgery. CONCLUSION: Although the tested patients were definitely no computer freaks, the procedure of the test was rapidly understood. The average testing time was 4.5 min, thus prolonged by 40% in comparison to assisted DIN testing, however consuming only 1.0 min of personnel's time. The test proved to be equally reliable in the elderly patient.
Aged↗
The Freiburg Visual Acuity test--automatic measurement of visual acuity.
The Freiburg Visual Acuity test is an automated procedure for self-administered measurement of visual acuity. Landolt-Cs are presented on a monitor in one of eight orientations. The subject presses one of eight buttons, which are spatially arranged on a response box according to the eight possible positions of the Landolt-Cs' gap. To estimate the acuity threshold, a best PEST (best Parameter Estimation by Sequential Testing) procedure is used in which a psychometric function having a constant slope on a logarithmic acuity scale is assumed. Measurement terminates after a fixed number of trials. With computer monitors, pixel-discreteness artifacts limit the presentation of small stimuli. By using anti-aliasing, i.e., smoothing of contours by multiple gray levels, the spatial resolution was improved by a factor of four. Thus, even the shape of small Landolt-Cs with oblique gaps is adequate and visual acuities from 5/80 (0.06) up to 5/1.4 (3.6) can be tested at a distance of 5 m.
Diagnosis, Computer-Assisted↗
Alexithymia in somatoform disorder and somatic disease: a comparative study.
BACKGROUND: The clinical validity of the newly developed 20-item Toronto Alexithymia Scale (TAS-20) with regard to the concept of somatization remains to be further established. This study attempts to determine the relationship between alexithymia and measures of psychopathology and illness severity in patients with somatoform disorders as compared to patients with chronic medical illness. METHODS: Forty inpatients with a DSM-III-R somatoform disorder and 29 inpatients with a chronic medical illness completed the German version of the TAS-20, SCL-90-R, Whiteley Index, and a global rating of the severity of current psychosocial impairment. RESULTS: Patients with a somatoform disorder scored significantly higher on the TAS-20 than the medically ill. As a result of stepwise multiple regression analysis, the SCL-90-R somatization scale emerged as a significant predictor of alexithymia in the somatizing patients, while the SCL-90-R depression scale and the severity of psychosocial impairment significantly predicted alexithymia in the medically ill. CONCLUSIONS: The results underline the clinical validity of the TAS-20 (German version) as well as the alexithymia construct.
Adolescent↗
Pattern, flicker, and flash electroretinography in human immunodeficiency virus infection: a longitudinal study.
To study electroretinographic (ERG) changes in the course of human immunodeficiency virus (HIV) disease, 42 eyes without retinitis were examined twice or more. During 9.6 months of mean observation time the visual acuity did not change. We found progressive functional impairment for the first, second, and third neurons of the visual pathway: the pattern-ERG amplitude (retinal ganglion-cell function) decreased by 11%, the b-wave amplitude (bipolars mediated by Müller cells) decreased by 13%, and the a-wave amplitude (dominated by rods) diminished by 21%. The flicker amplitude (dominated by cones) decreased by 20%. All of the latter four changes were significant (P < 0.02). Damage to the retina in HIV infection cannot solely be explained by visible changes in HIV retinopathy.
Adult↗
Pattern electroretinogram and computerized optic nerve-head analysis in ocular hypertension--interim results after 2.5 years.
Evidence exists that both the pattern electroretinogram (PERG) as a parameter of ganglion-cell function and computerized morphometric disc analysis (ONHA) predict subsequent glaucomatous visual field defects in ocular hypertensive eyes. Since November 1991 we have conducted a prospective longitudinal study to evaluate the suitability of PERG and ONHA for detecting incipient glaucoma damage. Inclusion criteria were: an intraocular pressure of > or = 25 mmHG (at least two measurements taken on different days) or, in eyes with additional risk factors, > or = 23 mmHG; a normal Octopus visual field (mean defect < or = 2 dB, no local defect); and no definite glaucomatous disc cupping. After a mean follow-up period of 14.6 +/- 8.8 (range 1-33) months and with a mean intraocular pressure of 24.4 (range 18-42) mmHg, none of the 66 patients (115 eyes) converted to glaucoma. Furthermore, PERG and ONHA do not agree in their estimation of the glaucoma risk at this stage.
Electroretinography↗
[Validation of the German version of the 20-item Toronto Alexithymia Scale in normal persons and psychiatric patients].
This paper describes the cross-validation of the German version of the 20-Item Toronto Alexithymia Scale (TAS-20) in normal adults (n = 306) as well as in a psychiatric inpatients sample (n = 101). The scale showed adequate estimates of internal consistency, split-half and test-retest reliability, and a three-factor structure comparable to that obtained for the English version of the TAS-20 which was found to be consistent with the main features of the alexithymia construct. Evidence of convergent validity of the German TAS-20 was demonstrated by significant positive correlations with conceptual related psychometric scales. The finding of significantly higher alexithymia scores in the psychiatric patients sample as compared to normal adults underlined the clinical validity of the German version of the TAS-20.
Adolescent↗
Pharmacological and biochemical characterization of the mouse 5HT5A serotonin receptor heterologously produced in the yeast Saccharomyces cerevisiae.
The cDNA for the mouse 5HT5A receptor has been functionally expressed in the unicellular yeast Saccharomyces cerevisiae. The NH2-terminal end of the receptor gene was fused to the Bacillus macerans (1-3, 1-4)-beta-glucanase signal sequence to ensure proper membrane insertion and to the c-myc epitope to permit immunological detection of the heterologously expressed protein. In the resulting episomal yeast expression plasmid pCNNmm5HT5A the modified 5HT5A gene is under the transcriptional control of the endopeptidase B gene promoter (PRB1). After transformation of the vector into the protease deficient S. cerevisiae strain cI3-ABYS-86, recombinant clones were examined for the presence of functional receptor by radioligand binding using [3H]LSD. Whole cells as well as crude membrane preparations of recombinant clones showed saturable binding of the receptor with a KD of approximately 2.2 nM. The pharmacological properties for the heterologous expressed receptor, estimated by ligand-displacement studies using certain serotonin agonists and antagonists, were comparable to those reported for the receptor expressed in mammalian systems. Western blot analysis of membranes prepared from a recombinant clone using the monoclonal antibody 9E10, directed against the c-myc epitope of the modified receptor, revealed an apparent molecular mass of about 43 kDa for the receptor expressed in S. cerevisiae. Glycosylation of the receptor was analysed by EndoH digestion. A heat shock of recombinant yeast significantly increased the number of specific binding sites per cell and also improved the affinity of the receptor. Immunogold electron microscopy was used to study the localization of the heterologously expressed protein within the yeast cells.
Amino Acid Sequence↗
High level production and localization of bovine rod cGMP-gated cation channel subunit 1 in baculovirus-infected insect cells and Saccharomyces cerevisiae.
The cGMP-gated cation channel is responsible for the last step in the vertebrate phototransduction cascade which couples light activation of rhodopsin to a change in membrane permeability. Two different expression systems, baculovirus-infected Spodoptera frugiperda (Sf9) insect cells and Saccharomyces cerevisiae, were used for the overproduction of the cGMP-gated cation channel subunit 1 of bovine rod cells. Presence of recombinant channel protein was monitored by SDS-PAGE and Western-blot analysis. Through immunogold labeling, the heterologously expressed cation channel was found to be localized predominantly in the inner compartments of the infected insect cells and in the vacuole of recombinant yeast cells.
Animals↗
Characterization of the rat m3 muscarinic acetylcholine receptor produced in insect cells infected with recombinant baculovirus.
The m3 muscarinic acetylcholine receptor from rat heterologously produced in insect cells after infection with a recombinant baculovirus has an apparent molecular mass of approximately 75 kDa. Polyclonal antibodies raised against a carboxy-terminal nonapeptide that is unique to the m3 subtype can detect the receptors produced in the insect cells by Western blot and can also immunoprecipitate solubilized receptor. Immunofluorescence microscopy as well as electron microscopy revealed that the receptor was located intracellularly, visualized as a ring around the nucleus of the infected insect cells. Solubilization of the receptor was accomplished with digitonin which was added in increments (over 10 min) to a final concentration of 0.8% (mass/vol). The solubilized receptor is unstable when the ligand-binding site is not protected by a ligand. Here the low-affinity ligand propylbenzilylcholine (approximately 10 nM) has demonstrable protective ability during solubilization, but the usefulness of this ligand is limited by a very slow off rate. From the behaviour of the solubilized receptor during DEAE-Sephacel chromatography and lectin-affinity chromatography it can be deduced that the receptor produced in insect cells is heterogeneously glycosylated in the producing insect cells.
Affinity Labels↗
Alexithymia, obesity, and binge eating disorder.
Eighty-three obese subjects with binge eating disorder (BED) were compared with 99 obese subjects not meeting criteria for BED on the Toronto Alexithymia Scale (TAS). Overall, the subjects in our sample were not significantly alexithymic, the mean global TAS score being 62.8 (SD = 10.2) which is comparable with the values found in non-patient control samples. Furthermore, the mean TAS scores did not differ between obese subjects with and without BED. However, we found a slightly higher prevalence of alexithymia (TAS total score 74 and above) in BED subjects compared with non-BED subjects (24.1% and 11.1%, respectively). A series of stepwise multiple regression analyses were run, exhibiting a significant relationship between the TAS and educational level and the Eating Disorder Inventory (EDI) subscales Interpersonal Distrust and Ineffectiveness. Age, body mass index, measures of depression, and eating pathology did not predict TAS scores.
Adult↗