Biomedical subjects
Publications and source records attributed to A Hosaka.
We describe two children who after cardiopulmonary arrest developed hypernatremia at the terminal stage. Urinary antidiuretic hormone concentration was very low, indicating central diabetes insipidus. These cases illustrate the necessity of alertness to the development of central diabetes insipidus in patients with severe hypoxic brain damage.
A very rare occurrence of adult granulosa cell tumor of the ovary (not of the juvenile type) causing precocious pseudopuberty in a six-year-old girl is described. An additional feature of interest was that the tumor appeared entirely cystic. To our knowledge, this condition in such a young premenarchal patient has not been reported previously.
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We induced myopia by eyelid suturing in one eye each of six 9-month-old cynomolgus monkeys to elucidate the condition by studying changes in the ocular structure and the blood-ocular barrier (BOB) permeability. Optical elements were measured by A-mode ultrasonography; vitreous fluorophotometry was carried out to document BOB permeability before eyelid suturing and 3, 10, 16, and 28 months after suturing. The axial length of the sutured eyes increased significantly compared with that of the non-sutured contralateral eyes at 10 months after suturing and continued to lengthen with time. The dioptric power (D) of the sutured eyes changed in the same way. (mean, -3.08D 28 months after suturing). The permeability of the blood-retinal barrier of the sutured eyes significantly increased from 10 months after suturing compared with that of the fellow eyes, and continued to increase over the period of observation. The permeability index of the blood-aqueous barrier also increased significantly from only 16 months after suturing further increasing as the period of observation lengthened. We hypothesize that in the transition from emmetropia to myopia, the permeability of the BOB rises, and continue to rise as myopia develops. Thus, the breakdown of the BOB, i.e., the breakdown of the ocular homeostasis, is considered to be closely related to the occurrence and the development of myopia.
Vitreous fluorophotometry (VFP) was performed for myopic eyes induced by unilateral eyelid suturing of six young cynomolgus monkeys in order to study the permeability of the blood-ocular barrier. The eyelid fusion was temporarily cut and opened at about five-month intervals, and the dioptric power and axial length of test and control eyes were measured. VFP was carried out before and after intravenous injections of fluorescein-Na. The inward permeability of the blood-retinal barrier (P(in)) was estimated by our computer simulation method, and the index of permeability of the blood-aqueous barrier (AQ) was also obtained. Significant prolongation of the length of the vitreous cavity was first seen 10 months after suturing, with the degree of myopia progressing subsequently. P(in) and AQ values increased as myopia progressed: significant increases were observed at 10 and 16 months after suturing, respectively. These results indicate a close relationship between the occurrence and progress of myopia and increased permeability of the blood-ocular barrier.
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A 3-year-old girl with status asthmaticus developed a grand mal seizure in association with hyponatraemia after 16 h of fluid therapy. Urinary arginine vasopressin (AVP) was elevated during the attack and rose strikingly before the onset of the convulsion. In 13 of 17 other patients with moderately severe asthmatic attacks, increases in urinary AVP levels occurred before the initiation of treatment. Dilutional hyponatraemia (water intoxication) must be prevented in patients with severe asthmatic attacks in whom diuretic capacity is impaired.
From Japanese population studies the following is summarized: 1) The refractive condition in each person is mainly determined by the axial length. 2) The axial length of the eye depends mainly on the length of vitreous cavity. 3) The anterior part of the eye, that is from the corneal surface to the posterior surface of the lens, may differ from individual to individual. 4) However, the differences found are rather small, and anterior segment axial distances do not play an important role regarding refractive value.
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Vitreous fluorophotometry was performed in 165 eyes of 93 cases with various degrees of myopia. The age range was 10-39 years. On background of the significant correlation between the refractive diopter value and the length of vitreous cavity, a simulation model for myopia has been established for assessing the permeability of the blood-retinal barrier. Significant negative correlations between the diopter and P-in and the diopter and D-p were found, indicating that by increasing degree of myopia, the functional disorder of the blood-retinal barrier and the liquefaction of the posterior vitreous gel progress. From the comparative study between eyes with slight myopia and eyes with emmetropia, a significant increase in the length of the vitreous cavity and P-in was found in the former, whereas no significant difference was observed in D-p. Therefore, it is suggested that the functional disorder of the blood-retinal barrier in myopia produces the liquefaction of the posterior vitreous gel.
In order to normalize the condition of pseudomyopia, the following can be summarized: One percent cyclopentolate was effective in 63%, and 0.4% tropicamide was effective in 59% of the cases. With a value of 68% after labetalol eye drops there were no significant differences in efficacy between this drug and the above cycloplegics. In subjects treated only with placebo, 4 out of 16 eyes, i.e. 25% were relieved. A significant difference (P less than 0.01) was found between the results with the above 3 drugs and placebo. On the other hand, the efficacy of 0.25% timolol (effect in 28%) and chemical X (effect in 37%) were not significantly different from the effect of placebo, though the results with chemical X encourage further trials. It can be postulated that by releasing an abnormal tension cycloplegics reduce the myopic condition. Regarding the hypotensive action of beta-adrenergic blockers on intraocular pressure, it presumably depends mainly on inhibition of secretion in the ciliary body. The fact that labetalol appeared effective, and timolol not, in treatment trials of slight myopia might imply that the mechanism behind an effect of labetalol on slight myopia is not merely a beta-adrenergic blocking action.
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A 20% phenytoin (PHT) plain mixture with excipients (20%PM) and three PHT products prepared by wet granulation, which are 20% fine granule (20%FG), 99% air-dried fine granule (99%FG-A) and 99% freeze-dried fine granule (99%FG-F), were prepared. The extents of PHT absorption from these products and the Aleviatin Fine Granules (97%FG) prepared with microcrystalline PHT powder were compared with those from commercially available PHT powder (Aleviatin) and tablet (Hydantol Tablet 25 mg), which are of the Pharmacopoeia of Japan grade, in healthy adult volunteers. In single dose study, the extents of PHT absorption from the powder, 20%PM, 20FG, 99%FG-A, 99%FG-F, 97%FG and tablet were 89.7, 92.2, 99.0, 96.7, 99.1, 99.1 and 99.3%, respectively. The property of almost complete absorption of PHT from the product was shown in the 20%FG, 99%FG-F and 97%FG similar to the tablet. In multiple dose study, the minimum and the average estimated free concentrations of PHT at steady-state for 99%FG-F and 97%FG were nearly equal to those for the tablet, and were higher than those for the powder. In epileptic patients, the plasma PHT concentrations were increased when dosage form was changed from the powder to 99%FG-F. However, the plasma PHT concentrations were scarcely altered when dosage form was changed from the tablet to 99%FG-F. The change in dosage forms from the tablet to 99%FG-F and 97%FG or opposite direction can be done without causing toxicity in epileptic patients, so long as these products are used at the same amounts as PHT.