Biomedical subjects

A Kamata

Publications and source records attributed to A Kamata.

33 records · Page 2Linked to original sources

PubMed1994

Pharmacokinetic analysis of the absorption enhancing action of decanoic acid and its derivatives in rats.

The enhancing action of decanoic acid (C10) and its derivatives on mucosal absorption of phenolsulfonphthalein (PSP) in the jejunum or colon was analyzed using pharmacokinetics in rats. After administration of a solution containing PSP and an enhancer [C10, 2-hydroxydecanoic acid (2-OHC10), or 3-hydroxydecanoic acid (3-OHC10)] into the jejunal or colonic loop, the amounts of PSP and enhancer remaining in the loop and/or plasma PSP concentration were determined periodically. 2-OHC10 exhibited a greater absorption enhancing potency than C10, while 3-OHC10 was less effective. Disappearance of residual PSP from the loop ceased after complete absorption of the enhancer. The enhancer-induced disappearance rate constant of PSP correlated well with the product of the enhancer disappearance rate and its capacity to sequester calcium ions. In conclusion, the enhancement of PSP mucosal absorption by C10 and its derivatives is consistent with a pharmacokinetic model, assuming that the enhanced membrane permeability of PSP depends on the enhancer disappearance kinetics from the loop and its calcium ion sequestration capacity.

Animals↗

PubMed1993

Subclassification of preproliferative diabetic retinopathy.

One hundred and fifty-five eyes (106 cases) affected by preproliferative diabetic retinopathy were divided into three subgroups according to the severity of retinopathy and were followed for one year. The criteria for and numbers of eyes in each group were as follows: 1) mild type with soft exudates and without apparent nonperfused areas on fluorescein angiography (39 eyes), 2) moderate type with soft exudates and demonstrable nonperfused areas (103 eyes), 3) severe type with soft exudates, nonperfused areas and venous beading (13 eyes). The proportion undergoing photocoagulation was 23% in the mild type, 81% in the moderate type and 100% in the severe type. None of the mild type eyes underwent photocoagulation unless they advanced to a more severe type. Nine of the mild type eyes which progressed to moderate type during the follow-up period underwent focal photocoagulation. Panretinal photocoagulation was performed in 29% of moderate type eyes and 77% of severe type eyes. The courses of these three subgroups were analyzed after one year of follow-up. The proportion developing proliferative retinopathy was 0% in the mild type, 18% in the moderate type and 46% in the severe type. Based on the above results, it was concluded that the subclassification we proposed in this paper can be applied to the management of patients with preproliferative diabetic retinopathy.

Adult↗

PubMed1993

Clinical study of venous abnormalities in diabetic retinopathy.

The authors studied 304 eyes (248 cases) affected by diabetic retinopathy in relation to venous abnormalities. The posterior pole and surrounding mid-peripheral area were examined by ophthalmoscopy, slit-lamp examination with contact lens and fluorescein angiography. There were 225 eyes with preproliferative and 79 eyes with proliferative retinopathy. Fifty-six eyes (18%) of the total eyes had venous abnormalities: 17 (8%) of the 225 eyes with preproliferative retinopathy and 39 (49%) of the 79 eyes with proliferative retinopathy. In the 56 eyes with venous abnormalities, 54 (96%) showed beading, 14 (25%) showed looping and 2 (4%) showed duplication. All eyes which showed looping or duplication had proliferative retinopathy. The locations of the venous abnormalities were analyzed: 42% were in secondary branches, 27% in tertiary branches, 18% in primary branches, 10% in fourth branches and 3% in fifth branches. The portion of the fundus affected was upper temporal, lower temporal, upper nasal and lower nasal in 28%, 22%, 29% and 21%, respectively. Based on our results, eyes with looping or duplication on ophthalmoscopic or slit-lamp examination have an extremely high probability of being in some stage of proliferative retinopathy. Retinopathy should be confirmed by fluorescein angiography and photocoagulation should be performed as quickly as possible.

Diabetic Retinopathy↗

PubMed1993

[The sub-classification of pre-proliferative diabetic retinopathy].

The authors divided 155 eyes (106 cases) affected by pre-proliferative diabetic retinopathy into three sub-groups according to the severity of retinopathy and followed them for one year. The criteria for and numbers of eyes in each group were as follows; 1) mild type with soft exudate and without apparent non-perfused areas on fluorescein angiography (39 eyes). 2) moderate type with soft exudate and demonstrable non-perfused areas (103 eyes). 3) severe type with soft exudates, non-perfused areas and venous beading (13 eyes). The proportion undergoing photocoagulation was 23% in the mild type, 81% in the moderate type and 100% in the severe type. None of the eyes in the mild type underwent photocoagulation unless they advanced to a more severe type. Nine eyes of the mild type which progressed to moderate type during the follow-up period underwent focal photocoagulation. Panretinal photocoagulation was performed in 29% of moderate type eyes and 77% of severe type eyes. The courses of these three sub-groups were analyzed after one year of follow up. The proportion developing proliferative retinopathy was 0% in mild type, 17% in moderate type and 46% in severe type. Based on the above results, we conclude that the sub-classification we propose in this paper can be applied in managing patients with pre-proliferative diabetic retinopathy.

Diabetic Retinopathy↗

PubMed1992

[Clinical study of venous abnormalities in diabetic retinopathy].

The authors studied 304 eyes (248 cases) affected by diabetic retinopathy in relation to venous abnormalities by ophthalmoscopy, slit lamp examination with contact lens and fluorescein angiography. The posterior pole and surrounding mid-peripheral area were examined. The subjects consisted of 225 eyes with pre-proliferative and 79 eyes with proliferative retinopathy. Fifty-six eyes (18%) had venous abnormalities: 17 of the 225 eyes (8%) with pre-proliferative retinopathy and 39 of the 79 eyes (49%) with proliferative retinopathy. In the 56 eyes with venous abnormalities. 39 (96%) showed beading. 14 (25%) showed looping and 2 (4%) showed duplication. All eyes which showed looping or duplication had proliferative retinopathy. The locations of the venous abnormalities were analyzed: 42% were in secondary branches, 27% in tertiary branches, 18% in primary branches, 10% in fourth branches and 3% in fifth branches. The portion of the fundus affected was upper temporal, lower temporal, upper nasal and lower nasal in 28%, 22%, 29% and 21%, respectively. Based on our results, eyes with looping or duplication on ophthalmoscopic or slit lamp examination, have an extremely high probability of being in some stage of proliferative retinopathy. Retinopathy should be confirmed by fluorescein angiography and photocoagulation should be performed as quickly as possible.

Diabetic Retinopathy↗

PubMed1991

The risk of cerebral infarction in non-valvular atrial fibrillation: effects of age, hypertension and antihypertensive treatment.

The stroke risk was studied on 600 subjects with nonvalvular atrial fibrillation (NVAF) compared with the general population. The age-matched relative risk of stroke was highest in the 41- to 50-year-old population (12.6) but decreased with age (8.2 for 51-60 years, 3.6 for 61-70 years, and 2.6 for 71-80 years) owing to the increase in stroke incidence with age in the general population. There was no particularly vulnerable period for stroke from NVAF diagnosis until the 15the year. Stroke incidence was greater in hypertensives than in normotensives, but was not different between treated and untreated subjects among hypertensives.

Adult↗

PubMed1990

[Impairment of erythrocyte anti-oxidant defense mechanisms in hypoxemic patients].

Defense mechanisms against lipid peroxidation were studied in erythrocytes from hypoxemic patients. The levels of lipid peroxides in patients erythrocytes were higher than those of control subjects (15.3 +/- 10.9 vs 7.5 +/- 3.0, p less than 0.05). The levels of reduced glutathione (GSH) decreased in erythrocytes from the patients (426 +/- 108 vs 756 +/- 201, p less than 0.01). Activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD) were lower than those of control subjects (GPX; 27.6 +/- 7.1 vs 35.1 +/- 3.8, SOD; 76.6 +/- 42.9 vs 125.7 +/- 40.1, p less than 0.01). Positive correlations were observed between the levels of arterial oxygen pressures (PaO2) and the GSH concentrations, the activities of GPX and SOD, respectively. These data suggest that decreased anti-oxidant activity enhances lipid peroxidation in erythrocytes from hypoxemic patients.

Aged↗

PubMed1984