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Biomedical subjects

F Niermann

Publications and source records attributed to F Niermann.

4 recordsLinked to original sources
PubMed1991

[VECP (pattern threshold, amplitude, latency) in different light levels. A comparison between healthy eyes, organic and functional amblyopia eyes].

According to Bjerrum [5] and Ammann [2], light attenuation decreases visual acuity at different rates in normals, organic and functional amblyopes. In 27 normal subjects, 19 patients with central fixating squint amblyopia and 12 with organically poor vision, we determined the visually evoked cortical potential (VECP) threshold check size, P100 latency and P2 amplitude for reversing checkerboards of variable size at different levels of luminance. After light attenuation, we found a different rate of change for VECP threshold check size in normal subjects and patients with squint amblyopia, which lessened after the fovea was occluded. With suprathreshold checks, normal subjects and patients with squint amblyopia exhibited significantly smaller amplitude/latency changes after light attenuation than patients with organically poor vision. Only patients with squint amblyopia exhibiting a visual acuity of greater than 0.2 showed smaller VECP changes than normal subjects during light attenuation. According to these findings, the different rate of change in visual acuity after light attenuation in normal subjects and patients with squint amblyopia is locus specific [7] rather than luminance specific [12, 13]. We conclude that cortical disinhibition of the parafoveal retina [20] is responsible for the preservation of visual acuity in squint amblyopia during light attenuation.

Adolescent↗
PubMed1989

[Pattern electroretinography and pattern visual evoked potentials in maculopathy: a comparison with sensory tests].

The retinal and cortical potentials for pattern reversal were recorded in 58 eyes of 30 patients afflicted with macular disease. The highest incidence of abnormality (79%) was found for the amplitudes P-ERG and P-VECP. Total field EOG and L-ERG were affected less frequently (41% and 25%). The P-ERG amplitude correlated significantly with the sensitivity of the central 10 degrees visual field (static perimetry). The P-VECP threshold check size showed a close correlation with visual acuity. Thus, the recording of pattern-evoked retinal and cortical potentials serves as a supplementary means of assessing types of maculopathy.

Adolescent↗
PubMed1987

[Systolic and diastolic blood flow velocities in the left coronary artery before and following i.v. dipyridamole. Comparative measurements using a digital image processing in 2 unstenosed vessel branches].

The hemodynamic significance of coronary artery stenoses cannot be assessed by presently-used methods. Especially stenoses of small and moderate degree only reveal hemodynamic relevance during augmentation of coronary flow. It can be expected that the increase in flow is limited in a stenotic branch, compared with an unstenosed branch of the same vessel. The increase in coronary blood flow in two unstenosed branches of the same vessel, however, should be nearly identical. To prove this hypothesis, the relative increase in coronary flow was measured in two unstenosed branches of the left coronary artery by means of digital subtraction angiocardiography. Ten patients were examined before and after intravenous administration of 20 mg (on average 0.29 mg/kg body weight) dipyridamole. Dipyridamole resulted in an increase in the diameter of the left anterior descending branch (LAD) of 11% (p less than 0.005) and of the circumflex artery (RCx) of 13% (p less than 0.005). The increase in flow velocity during systole amounted to 49% in the LAD (p less than 0.001) and to 58% in the RCx (p less than 0.005); during diastole to 60% in the LAD (p less than 0.005) and 83% in the RCx (p less than 0.005). The increase in volume flow during systole amounted to 78% in the LAD (p less than 0.005) and to 89% in the RCx (p less than 0.005), during diastole to 84% in the LAD (p less than 0.005) and to 113% in the RCx (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗