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Biomedical subjects

Y Oku

Publications and source records attributed to Y Oku.

192 records · Page 11Linked to original sources
PubMed1978

Homovanillic acid in human cerebrospinal fluid.--Its concentration gradient and reduced levels in patients with epilepsy.

The homovanillic acid (HVA) concentrations in the lumbar cerebrospinal fluid (CSF) were determined in 38 epileptic and 39 control patients. The mean concentration of HVA was 23.9 ng/ml +/- 2.8 SEM for the epileptic group and 30.2 ng/ml +/- 2.1 SEM for the control group, respectively. Thus, HVA was significandly reduced in the patients with epilepsy compared with the controls. The mean HVA in the female patients was higher than in the male patients in both groups but this failed to reach statistical significance. There was no apparent relationship between the degree of reduced HVA concentration and other clinical indexes of the epilepsy (age, type and frequency of seizures, and anticonvulsant medication). For the determination of concentration gradient of HVA three fractions of the spinal CSF were obtained from 11 patients. A pronounced gradient of HVA concentration was found with a ratio of 1 : 1.46 : 1.97 for the first, second and third fractions. This suggests that a standardized conditions for collecting CSF should be employed to study HVA levels in humans.

Adult↗
PubMed1976

Neuroepithelial Cyst of the cerebellar vermis.

A cyst located in the cerebellar vermis and causing obstructive hydrocephalus is described. The wall of the cyst was lined with ciliated and non-ciliated cuboidal epithelial cells which were completely invested by a basement membrane.

Adult↗
PubMedDate not supplied

Perceptual contributions to optimization of breathing.

Besides regulating the energetic cost of breathing, optimization of breathing may involve the alleviation of an uncomfortable breathing sensation. In this article, we consider perceptual contributions to the optimization of breathing. Just as the cost function proposed by Poon depends on ventilation and arterial PCO2 so does the sense of dyspnea. Consequently, we examined the relationship between breathing discomfort and Poon's cost function. Based on our model and psychophysical studies, it appears that breathing discomfort, which can integrate chemical and mechanical inputs to the respiratory controller, may not operate simply as an estimate of a cost function. We explain how our reflex control model can dynamically minimize a cost function such as Poon's. Also, we consider the influence of willful adjustments of ventilation on breathing discomfort. From this we infer that ventilatory optimization may emerge from automatic reflexes and behavioral responses that involve excitatory chemical and inhibitory neuromechanical feedbacks.

Dyspnea↗