Biomedical subjects

K Brendler

Publications and source records attributed to K Brendler.

3 recordsLinked to original sources

PubMed1998

Eye movements in reading with hemianopic field defects: the significance of clinical parameters.

BACKGROUND: Reading disability is the main problem in patients with hemianopic field defects (HFD). The purpose of this study was to examine eye movement patterns in HFD with special emphasis on the importance of clinical parameters. METHODS: 40 patients with HFD (21 left, 19 right) and 21 normal subjects were examined by an infrared reflection system to record eye movements during reading and by Tübingen perimetry. Reading and clinical parameters were correlated. RESULTS: Reading speed was reduced in all patients compared to normal subjects (853 vs 1541 characters/min), in right (785 char/min) more than in left HFD (915 char/ min). The number of saccades and regressions per line was markedly increased in right HFD (9.8 vs 4.5; 2.2 vs 0.3), less so in left HFD (6.4; 1.0). The number of saccades during the return sweep was more increased in left HFD (1.5 vs 0.5) than in right HFD (0.9). Reading parameters improve with increasing distance of HFD to the visual field center (minimum in right HFD 5 degrees, in left HFD 2 degrees) and with increasing time since onset. Some left HFD patients learn a predictive strategy for the return sweep. The effect is less pronounced for age and skill and is absent for the localization of the lesion. CONCLUSION: Patients with right HFD are more disabled. The side of the HFD, its distance to the visual field center and the time since onset are significant parameters for reading performance. The analysis of reading parameters in correlation with clinical parameters provides valuable information about the necessary perceptual field and learning effects and is helpful in rehabilitation.

Adult↗

PubMed1985

Effect of diltiazem on in vitro rabbit bladder function.

The relationship between extracellular calcium and urinary bladder function was investigated by studying the effect of the specific calcium antagonist diltiazem on the functional ability of the in vitro whole rabbit urinary bladder to empty in response to pharmacological stimulation. The bladder was found to require an extracellular calcium concentration of 4.5 X 10(-4) M to elicit near complete cholinergic-mediated emptying. Diltiazem (1 X 10(-6) - 1 X 10(-4) M) inhibition of bladder function was competitively antagonized by increasing the extracellular calcium concentration (0.45 X 10(-4) - 3.6 X 10(-4) M). In the absence of diltiazem, alterations in the extracellular calcium concentration between 0.45 X 10(-4) and 3.6 X 10(-4) M had no significant effects on bladder response to bethanechol. KCl-mediated bladder emptying was significantly more sensitive to diltiazem inhibition than was bethanechol-stimulated emptying. Even at the intermediate diltiazem concentration of 1 X 10(-5) M, increasing the extracellular calcium concentration did not completely reverse the inhibitory effect of diltiazem on bladder response to KC1. These findings are consistent with the hypothesis that diltiazem at low concentrations may inhibit extracellular calcium influx while at higher concentrations translocation of intracellular stores of calcium may be inhibited as well. The study also suggests that diltiazem is capable of inhibiting urinary bladder function and deserves further consideration as a possible therapeutic agent in certain forms of urinary bladder dysfunction.

Animals↗

PubMed1983

Comparative pharmacological response of an in vitro whole bladder preparation (rabbit) with response of isolated smooth muscle strips.

Although much of our knowledge of the pharmacological response of the urinary bladder comes from in vitro muscle strip studies, it is not clear if these studies can be directly correlated with bladder function. We have compared the pharmacological response of an in vitro whole bladder model with the response of the standard muscle strip technique. The whole bladder model has the advantage of being able to measure both the isometric contractile response to drugs as well as a functional response in which the bladder can empty in the presence of a constant resistance. The results of these studies may be summarized as follows: 1) bethanechol was equipotent in contracting the muscle strips and in the closed whole bladder model; 2) at low and intermediate bladder volumes, the bladder fully emptied at concentrations of bethanechol significantly below the concentration required for maximal contraction; 3) isoproterenol, a potent beta-adrenergic agonist, stimulated a strong relaxation in muscle strips, whereas the whole bladder responded very poorly to isoproterenol; 4) in muscle strips isoproterenol strongly antagonized bethanechol contraction, whereas, in the whole bladder system, isoproterenol did not significantly antagonize bethanechol contraction; 5) methoxamine and adenosine triphosphate produced a moderate, equipotent contraction in both models.

Adenosine Triphosphate↗