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Biomedical subjects

J Yamagami

Publications and source records attributed to J Yamagami.

27 records · Page 2Linked to original sources
PubMed1991

[Diurnal variation of intraocular pressure in low tension glaucoma].

Around-the clock intraocular pressure (IOP) measurement were performed in 104 eyes of 52 low tension glaucoma (LTG) cases. Subjects were all hospitalized and IOP measurements were done every 2 hours from 6:00 AM to 12:00 PM and every 3 hours from 12:00 PM to 6:00 AM. All LTG patients met the following criteria, (1) glaucomatous optic nerve head change and corresponding visual field defect, (2) normal open angle, (3) IOP less than or equal to 21mmHg at any time of IOP measurement, (4) no obvious neurological or rhinological disorders that could affect the optic nerve, (5) no history of hemodynamic crisis or cardiovascular disorders except mild hypertension. Peak IOPs were most frequently observed at 10:00 AM, but about 55% of all observed peaks were in the time period from 6:00 PM to 8:00 AM. Most troughs were observed from 2:00 PM to 10:00 PM. The mean IOP, the diurnal variation and the difference between both eyes in the same person averaged 14.1, 4.9, and 0.6mmHg, respectively. Assuming that the period of rhythm is 24 hours, the results of IOP measurements fitted a cosine curve using the least square method. In 44% of all eyes, significant correlation coefficient (r greater than or equal to 0.6, p less than 0.05) between the measured and the predicted IOPs was noted, and an equation, IOP = 14.3 + 1.7cos 2 pi (t/24-0.4 radian), was obtained. Comparing the present results with former ones, we concluded that the IOP changes in LTG patients were similar to those in normal individuals.

Circadian Rhythm↗
PubMed1990

[The influence of the intraocular pressure on the visual field of low tension glaucoma].

To study the effect of the intraocular pressure (IOP) on the visual field (VF) damage in low tension glaucoma (LTG), we compared the IOP and the VF damage in both eyes of 46 LTG patients. As an index of the VF damage, we used the mean deviation (MD) value calculated by the Humphry (30-2) STATPAC program, and for the IOP data, the mean of 24 hour IOP measurements (diurnal IOP) and the mean of the IOPs measured at each visit to our outpatient clinics (follow-up IOP). In 13 cases, the diurnal and the follow-up IOPs were 0.3 mmHg higher or more in the more damaged eye than those in the less damaged eye, and in 7 cases they were 0.3 mmHg higher or more in the less damaged eye than those in the more damaged eye. Between these two groups, no significant difference was seen in the value of MD, but the diurnal IOP and the follow-up IOP was significantly higher in the former than in the latter group. By discrimination analysis, the two groups were distinguished at the diurnal IOP of 14.1 mmHg (hit rate 77.6%) and the follow-up IOP of 15.0 mmHg (74.2%). An analysis using the whole 46 LTG cases yielded the following results: when the diurnal or follow-up IOP of the more damaged eye was higher than the above determined level, the IOP in the more damaged eye was significantly higher than that in the contralateral less damaged eye.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

An optimal method for calculation of the frontal-plane vector from the data of the standard and unipolar limb leads.

An optimal estimation of the frontal-plane cardiac vector (R, theta) was derived from the scalar ECG data of the standard and unipolar limb leads by the least square method which minimized the sum of squares of measurement errors of each lead data. The optimal vector was given by R = (Formula: see text) with V1, V2, V3, Vr, Vl and Vf being the measured values of the lead data. This estimation is optimal in that it coincides with the center of gravity of the vector obtained by using the two-lead data. A statistical evaluation of the reduction in measurement errors was performed.

Electrocardiography↗