Hideo Nishigori

Hepatocyte Growth Factor in Vitreous Fluid of Patients With Proliferative Diabetic Retinopathy and Other Retinal Disorders

OBJECTIVE To determine whether hepatocyte growth factor (HGF) is elevated in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR). RESEARCH DESIGN AND METHODS Vitreous fluid samples were obtained at the time of vitreoretinal surgery from 73 eyes of PDR patients and from 17 eyes of nondiabetic patients (control subjects) who had macular hole, rhegmatogenous retinal detachment, or epiretinal membrane (9, 4, and 4 eyes, respectively) but no associated proliferative vitreoretinopathy. Stages of PDR were classified as active or quiescent. Concentrations of HGF and vascular endothelial growth factor (VEGF) in vitreous fluid were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS Intravitreous concentrations of HGF (median [range]) were significantly higher in diabetic patients with PDR (6.00 ng/ml [0.75−22.2]) than in control patients (2.86 ng/ml [0.75−5.80]). Intravitreous concentrations of VEGF were also higher in diabetic patients with PDR (1.62 ng/ml [0.15−7.9]) than in control patients (0.16 ng/ml [0.16−0.29]). Both VEGF and HGF concentrations were significantly higher in patients with active retinopathy than in those with quiescent retinopathy. However, vitreous concentrations of HGF were unrelated to those of VEGF CONCLUSIONS We found that levels of HGF in vitreous fluid of PDR patients are significantly higher than in nondiabetic patients and that the levels of HGF are elevated in the active PDR stage. This suggests that HGF stimulates or perpetuates neovascularization in PDR.

Preventive effects of pyrroloquinoline quinone on formation of cataract and decline of lenticular and hepatic glutathione of developing chick embryo after glucocorticoid treatment

When 0.25 mumol of hydrocortisone succinate sodium (HC) was administered to 15-day-old fertile eggs, almost all lenses of chick embryos treated with HC for 48 hr were classified as cataract stage IV-V (95%). A triple application of potassium pyrroloquinoline quinone (PQQ) (1.25 mumol/egg) at 3, 10 and 20 hr after HC treatment showed a preventive effect against the HC-induced cataract formation (I:45%, II:25%, III: 30%). PQQ also prevented the decline of GSH in the lens caused by HC. The decline of GSH in liver 24 hr after HC administration was prevented by PQQ. These data indicate that PQQ can modify HC-induced effects and that the preventive effect of PQQ against HC-induced decline of hepatic GSH seemed to influence HC-induced events in lens.

The alteration of lipid peroxide in glucocorticoid-induced cataract of developing chick embryos and the effect of ascorbic acid

The level of lipid peroxide (LPO) in glucocorticoid-induced cataractous lenses was measured by using thiobarbituric acid. When 0.25 mumol of hydrocortisone hemisuccinate sodium (HC) were administered to 15-day-old chick embryos, the level of LPO in the lens increased to approximately 1.4-fold of the control level at 24 to 48 hr after HC treatment. However, the level returned to the control level by 96 hr with the disappearance of opacity in the lens. A triple application of ascorbic acid (20 mumol/egg) at 3, 10 and 20 hr after HC treatment prevented cataract formation and elevation in the level of LPO in 60% of the lenses. In 40% of the eggs treated with HC plus ascorbic acid, the results were no different than HC alone. Treatment with prednisolone hemisuccinate sodium (0.25 mumol/egg) produced an elevation in the level of LPO in the lens but that with cortisone hemisuccinate sodium or cortexolone hemisuccinate sodium did not change the level of LPO in the lens. The phenomena of the cataract formation and the elevation of LPO in the lens caused by HC seemed to be related to each other and due to its glucocorticoid activities.

Preventive effect of ascorbic acid against glucocorticoid-induced cataract formation of developing chick embryos

Glucocorticoid administration to developing chick embryos is known to promote cataract formation with a decreasing level of glutathione in the lens. To gain further understanding of this process, the level of ascorbic acid, a biological antioxidant, in the lenses was measured during the course of glucocorticoid treatment. When 0.25 mumol of hydrocortisone hemisuccinate sodium (HC) were administered to 15-day-old chick embryos, the level of ascorbic acid in the lens began to decline after 30 hr and became around 40% of the control value at 48 hr after HC treatment. At this time about 90% of the lenses showed opacity in the nuclear region. However, the level of ascorbic acid in the cataractous lens recovered to the control level at 96 hr, a time when the lens has recovered from cataract formation. A triple application of ascorbic acid (20 mumol/egg) at 3, 10 and 20 hr after HC treatment significantly prevented lens opacification. The administration of ascorbic acid prevented the decline of ascorbic acid content and partially that of glutathione content in the lens caused by HC.

Active removal of radioactivity in the blood circulation using biotin-bearing liposomes and avidin for rapid tumour imaging

In order to shorten the delay between the administration of tumour-imaging agents and obtainment of scintigrams, rapid delivery of radionuclide to tumours followed by rapid clearance from the blood is required. We used liposomes with biotin bound on their surface (B-liposomes) as carriers for rapid delivery. For rapid blood clearance, we employed avidin in the expectation that the strong affinity between biotin and avidin would result in the aggregation of B-liposomes in the blood circulation, and that these aggregates would be taken up rapidly by the reticuloendothelial system, resulting in the rapid elimination of liposomes and the radionuclide encapsulated in them. When B-liposomes encapsulating gallium-67 deferoxamine were intravenously administered to mice bearing sarcoma 180, large amounts of 67Ga were delivered to tumours by 4 h after injection, though the 67Ga blood level remained high. On the other hand, administration of avidin 4 h after administration of the B-liposomes dramatically reduced the blood level so that it was only 5% of that in the non-treated group 1 h later. As a result, the tumour-to-blood ratio reached nearly 14 at 5 h after radionuclide administration, suggesting that rapid tumour-imaging will be feasible by means of this method.

Establishment of a chick embryo shell-less culture system and its use to observe change in behavior caused by nicotine and substances from cigarette smoke

Early detection and removal of harmful factors are essential to the proper physical and psychological development of the fetus, presumably showing the effects during the prenatal period and after birth. As one procedure to aid in understanding such factors, we have established a shell-less culture system for video monitoring to observe change in behavior of 7-day-old chick embryos. Nicotine and aqueous cigarette smoke extract (ACSE) were selected for the present experiments, and the results showed a complete stoppage of swing-like movements by administrations of 10 microg nicotine and 1xACSE, possibly displaying paralytic symptoms. Quantitative analysis of nicotine in 1xACSE indicated that more than 10 microg of nicotine were contained in 100 microl of the extract. The present system, although in initial stage of development, may be a useful preliminary screening procedure for perhaps supervision and warning about the environment surrounding pregnant women.

Alteration of hepatic lipidperoxide levels during cataract formation caused by glucocorticoids in developing chick embryos

The level of hepatic lipidperoxides in chick embryos was determined during cataract formation resulting from glucocorticoid treatment. When 15 day old chick embryos were administered 0.25 mumol of hydrocortisone acetate their hepatic lipidperoxide level, determined by thio-barbituric acid, increased after a lag time of 20 hr and reached approximately 8-fold of control at 48 hr after the treatment. These studies indicate that the peroxidation of lipid in tissues should be considered in elucidating mechanisms of action or adverse effects of glucocorticoids.

Development of a liposome-encapsulated radionuclide with preferential tumor accumulation—the choice of radionuclide and chelating ligand

Various radionuclide-ligand complexes were encapsulated in liposomes and their accumulations in tumors were studied. Increased tumor accumulation was observed with every complex in the liposome-encapsulated form. However, different accumulation levels were registered for the various radionuclides even though they were all delivered using a similar liposome formulation. Though the liposomes remained intact in the circulation, they were degraded in the tumor, liver and spleen eventually. Thus, this suggests that tumor accumulation of liposome-encapsulated radionuclides is dependent on not only the in vivo behavior of the liposomes themselves, but also the characteristics of nuclide-ligand complexes after their release from liposomes. A correct choice of radionuclides and ligands for encapsulation in liposomes would enable excellent tumor-imaging agents to be achieved.

The Hen's fertile EGG screening test (hest) : a comparison between the acute toxicity for chick embryos and rodents of 20 drugs

The possibilities of using developing chick embryos for evaluating drug activities and toxicities were studied by determining LD50 values for 20 drugs with 14 different pharmacological activities. Fifteen-day old chick embryos received drugs through the air cell and deaths were measured at 48 hr after the treatments. The LD50 values were determined and compared to the i.v., i.p., s.c. and p.o. values from mice listed in the Registry of Toxic Effects of Chemical Substance. The systemic toxicity of 15-day-old chick embryos to drugs were similar to those of mice with the following exceptions. The chick embryos seemed to be more sensitive than mice to antineoplastic or antibiotic agents such as actinomycin D and doxorubicin, whereas, LD50 values of cholinergic and cholinergic blocking drugs by this method were 10 to 20 fold of LD50 (i.v.) of mice. These observations are important for applying the hens fertile screening test (HEST) to the determination of drug activities other than that of embryo toxicity or teratogenic activity.

Alteration of Activities of Hepatic Antioxidant Defence Enzymes in Developing Chick Embryos After Glucocorticoid Administration ‐ A Factor to Produce Some Adverse Effects?

Liver tissue is one of the principal targets of glucocorticoids, therefore changes in the balance between hepatic oxidative and reductive capacity may greatly influence adverse effects of glucocorticoid therapy. In this study, effects of glucocorticoid on the activities of hepatic antioxidant defence enzymes were examined by using developing chick embryos.