Biomedical subjects

H Isono

Publications and source records attributed to H Isono.

At least 37 records · Page 2Linked to original sources

PubMed1997

Cytotoxicity of organochlorine pesticides and lipid peroxidation in isolated rat hepatocytes.

The cytotoxicity and lipid peroxidation of pesticides containing a halogen group were examined in isolated rat hepatocytes. We examined 9 pesticides of 3 different representative chemical families, chlorinated aromatic fungicides (pentachlorophenol (PCP), pentachloronitrobenzene (PCNB), chlorothalonil, fthalide), polyhaloalkylated thio fungicides (dichlofluanid, captan) and diphenyl ether herbicide (2,4-dichlorophenyl 4-nitrophenyl ether (NIP), 4-nitrophenyl2,4,6-trichlorophenyl ether (CNP), chlomethoxynil). The contents of the hydroperoxides in phospholipid, phosphatidylcholine hydroperoxide (PCOOH) and phosphatidylethanolamine hydroperoxide (PEOOH) were determined by the HPLC-chemiluminescence (CL-HPLC) method, which is sensitive and specific for lipid hydroperoxide. Chlorothalonil, dichlofluanid and captan were the most potent cytotoxicants evaluated by lactate dehydrogenase (LDH) leakage. PCP, NIP and CNP exhibited intermediate cytotoxicity. PCNB, fthalide and chlomethoxynil showed low cytotoxicity. The cellular phospholipid hydroperoxide (PCOOH and PEOOH) levels were remarkably increased by chlorothalonil (PCOOH, 23 times and PEOOH, 7 times), dichlofluanid (PCOOH, 523 times and PEOOH, 22 times) and captan (PCOOH, 518 times and PEOOH, 16 times) as compared with the control group. The PCOOH content was slightly increased by PCP (4.8 times) and NIP (6.3 times), whereas the other 4 pesticides did not change the phospholipid hydroperoxide level. Severe cytotoxicity was observed with a remarkable increase of phospholipid hydroperoxide by chlorothalonil, dichlofluanid and captan.

Animals↗

PubMed1997

The effect of magnesium on the fine structure of the golden hamster parathyroid gland in vivo and in vitro.

We examined the effect of magnesium (Mg) on the fine structure of the golden hamster parathyroid gland in vivo and in vitro. In the in vivo study, the principal changes in the parathyroid glands 10 and 30 min, and 1 hr after Mg injection showed a significant decrease in the area of the Golgi apparatus and cisternae of the rough endoplasmic reticulum compared with those of the control animals. The serum calcium level in the experimental animals 30 min and 1 hr after the injection was significantly low compared with that of the control animals. In the vitro study, the area of the Golgi apparatus in the Mg-treated group significantly decreased as compared with that of the control group. These changes suggest that Mg directly suppresses the synthesis of hamster parathyroid hormone in the short term.

Animals↗

PubMed1997

Effect of centrifugation on the ultrastructure of the parathyroid gland of the magnesium-treated golden hamster.

The ultrastructure of the parathyroid glands (PTG) of magnesium (Mg)-treated golden hamsters exposed to centrifugation at 1.2 G for 7 days was compared to that of the control, Mg-treated or centrifuged groups. In the PTG of the Mg-treated group exposed to centrifugation, the Golgi apparatus increased compared with that of the Mg-treated group, but was similar to that of the control and centrifuged groups. The cisternae of the rough endoplasmic reticulum (rER) increased compared with that of the Mg-treated group and decreased compared with that of the centrifuged group, but was the same as that of the control group. There were no significant differences among the 4 groups with regard to lysosomes, large vacuolar bodies, lipid droplets and secretory granules. These observations suggest that the rER is sensitive to centrifugation compared with the Golgi apparatus and more importantly the inhibitive effect of Mg on the synthesis of the hamster parathyroid hormone is enfeebled by centrifugation at 1.2 G.

Animals↗

PubMed1997

Nuclear bodies of the human lung in psittacosis.

Lung piece obtained from a female patient with psittacosis by biopsy. A nuclear bodies of five different types were observed, depending on their degree of ultrastructural development. First type showed fibrillary nuclear bodies surrounded by a clear halo. Type II resembled the nuclear body of type I but showed heterogeneously electron density. Type III comprised nuclear bodies with a fibrillary cortex containing a central granular component. These bodies were separated from the nucleoplasm by a clear halo. Type IV was characterized by a more complex structure and resembled the nuclear body of type III but with dense osmiophilic granules. Nuclear bodies of type V were comprised of numerous osmiophilic granules.

Cell Nucleus↗

PubMed1997

[Angiography by scanning laser ophthalmoscope with fluorescein compounds of different physicochemical properties].

We performed angiography in photocoagulated eyes using four fluorescent dyes that have different molecular weight, lipid solubility, and electric charge. These findings were compared with those of sodium fluorescein (Naf) and indocyanine green (ICG). Angiograms were obtained with Naf, ICG and two fluorescein isothiocyanate dextrans at different molecular weight (FITC-D4: MW 4,400, FITC-D40: MW 38,900). We also used two other dyes: carboxyfluorescein (Caf: less lipid soluble) and calcein (Calc: a highly negatively charged molecule). Two and four days after laser photocoagulation of retina, dye leakage was still evident at the photocoagulated sites with Naf, Caf, Calc and FITC-D4. Angiograms taken after Caf and Calc injection showed more intense and rapid dye leakage than with Naf. Contrary to this, little dye leakage was observed with ICG and FITC-D40. These findings indicated that the critical molecular weight for permeation lay between 4,400 and 38,900 once the breakdown of blood retinal barrier occurred. In addition, difference in molecular weight is a major factor determining dye permeability at the photocoagulated retinal lesions, among other possibilities such as lipid solubility and electric charge.

Animals↗

PubMed1997

Effects of short-term treatment with CaCl2 or EDTA on the parathyroid glands in pregnant golden hamsters, with special reference to large vacuolar bodies.

The large vacuolar bodies in the parathyroid glands of pregnant golden hamsters after administration of CaCl2 or EDTA were investigated. In the parathyroid glands of the pregnant animals 15 min after administration of CaCl2, the mean serum calcium concentration was significantly high when compared to that of the control animals. In the parathyroid glands of the pregnant animals 15, 30 and 60 min after administration of EDTA, the mean serum calcium concentration was significantly low when compared to that of the control animals. In the parathyroid glands of the pregnant animals 15 min after administration of CaCl2, the percentage area occupied by large vacuolar bodies was significantly increased when compared to that of the control animals. In the parathyroid glands of the pregnant animals 15 min after administration of EDTA, the percentage area occupied by large vacuolar bodies was significantly decreased when compared to that of the control animals.

Animals↗

PubMed1997

[Analysis of choroidal blood flow by laser speckle flowgraphy].

We applied real-time laser speckle flowgraphy (RLSFG) to quantitate the choroidal circulation. RLSFG was developed utilizing the laser speckle phenomenon. A diode laser, 830 nm in wavelength, serves as the light source. The quantitative index of blood flow velocity is represented as normalized blur (NB), or square blur rate (SBR). This method was applied to the posterior fundus of monkey and human eyes. While one measurement covers a fundus area of 1 mm x 1 mm, it is possible to measure a wider fundus area by montage. The wide color maps showed the architecture of choroidal vessels. It was possible to measure the choroidal blood flow in areas free of major retinal vessels. Application of the method to 3 eyes of retinal artery occlusion and 4 eyes of geographic choroiditis showed that the obtained SBR values in normal fundus is derived 25% from the retinal and 75% from the choroidal circulation. The findings show the potential value of RLSFG in quantitating the choroidal blood flow in situ.

Animals↗

PubMed1996

Impairment of inhibition of unattended stimuli in schizophrenic patients: event-related potential correlates during selective attention.

Auditory event-related potentials (ERPs) were recorded during a dichotic listening task in 18 remitted schizophrenic patients and in 18 age-matched controls. The subjects were instructed to press a button in response to the target tones applied to one designated ear. In schizophrenic patients, P300 amplitude for attended target was significantly smaller than in controls. Schizophrenic patients also exhibited reduced positive potentials between 200 and 400 ms in ERPs for unattended nontarget. These results suggested that schizophrenic patients lack the ability to inhibit unattended or irrelevant stimuli, in addition to impairment of 'context closure' in the information processing.

Adult↗

PubMed1996

Ultrastructural changes in water-clear cells of the golden hamster parathyroid gland after streptozotocin treatment.

The effects of streptozotocin treatment on parathyroid water-clear cells in golden hamsters were investigated. In the cytoplasm of the water-clear cells, lipid droplets were increased as compared to that of the control animals. This finding suggests that treatment of streptozotocin affects functional activity in the parathyroid water-clear cells of the golden hamsters.

Animals↗

PubMed1995

Effects of progesterone on the ultrastructure of the golden hamster parathyroid gland.

The ultrastructure of the parathyroid glands in golden hamsters after administration of progesterone was investigated. In the parathyroid glands of the female hamsters after administration of progesterone, the mean serum calcium concentration was significantly higher when compared to that of the control hamsters. In the male experimental hamsters, the percentage area occupied by Golgi complexes and lipid droplets was significantly increased when compared to that of the control hamsters, respectively. In the female hamsters after administration of progesterone, the percentage area occupied by large vacuolar bodies was significantly decreased when compared to that of the control hamsters. In the male and female experimental hamsters, the mean number of secretory granules per 100 microns2 of cytoplasm showed a significant increase compared with that of the male and female control hamsters, respectively. These findings suggest that the secretory activity of the parathyroid glands may be stimulated in response to hypocalcemia induced by progesterone.

Animals↗

PubMed1994

Cytotoxicity of 1,3-dichloropropene and cellular phospholipid peroxidation in isolated rat hepatocytes, and its prevention by alpha-tocopherol.

1,3-Dichloropropene induced time- and dose-dependent toxicity and lipid peroxidation were examined in isolated rat hepatocytes. HPLC method with chemiluminescence detection (CL-HPLC) was employed to determine phosphatidylcholine hydroperoxide (PCOOH) and phosphatidylethanolamine hydroperoxide (PEOOH) contents. The release of lactate dehydrogenase (LDH) as a toxicological parameter was significantly increased after 90 min incubation at 1 mM of 1,3-dichloropropene and after 60 min incubation at 5 mM, respectively. The cellular PCOOH and PEOOH contents were increased after 90 min incubation at 1 mM of 1,3-dichloropropene, and after 15 min for PCOOH and 30 min for PEOOH at 5 mM, respectively. The increase of cellular phospholipid hydroperoxide preceded the cytotoxicity. Hepatotoxicity was effectively prevented by preincubation with d,1-alpha-tocopherol (alpha-toc.) accompanied by prevention of the membrane phospholipid peroxidation. In conclusion, the peroxidation of phospholipid preceded cytotoxicity, and cytotoxicity was effectively prevented by alpha-toc. These results indicated that the peroxidative degradation of membrane phospholipid is one of the main causes of cytotoxicity by 1,3-dichloropropene.

Allyl Compounds↗

PubMed1994

Cytotoxicity of chlorinated hydrocarbons and lipid peroxidation in isolated rat hepatocytes.

The effects of 11 chlorinated hydrocarbons on toxicological parameters and lipid peroxidation were examined in cultured rat hepatocytes. The cytotoxicity was evaluated by measuring the lactate dehydrogenase (LDH) released and the protein amount in cells attached to culture dishes. Phosphatidylcholine hydroperoxide (PCOOH) and phosphatidylethanolamine hydroperoxide (PEOOH) levels were determined by HPLC with chemiluminescence detection (CL-HPLC). Severe cytotoxicity was observed under the presence of the carbon tetrachloride, 1,1,1-trichloroethane, tetrachloroethylene and 1,3-dichloropropene in a concentration of 10 mM. The cellular PCOOH and PEOOH levels were remarkably increased (more than 4 times) by adding these 4 chlorinated hydrocarbons. The other 7 chlorinated hydrocarbons examined did not cause any change on the cellular phospholipid hydroperoxide levels, and showed lower or no cytotoxicity at a concentration of 10 mM. The peroxidative degradation of membrane phospholipids may play an important role in causing the cytotoxicity of some chlorinated hydrocarbons.

Animals↗

PubMed1994

Effects of prostaglandin E2 on the ultrastructure of the golden hamster parathyroid gland.

The effects of different ages on large vacuolar bodies in the parathyroid glands of golden hamsters after administration of prostaglandin E2 (PGE2) were investigated. In the parathyroid glands of the young and senile animals 15 min and the senile animals 60 min after administration of PGE2, the mean serum calcium concentration was significantly higher when compared to that of the young and senile control animals, respectively. In the experimental adult animals 60 min after administration of PGE2, the serum calcium concentration was seen to increase. In the parathyroid glands of the young animals 15 min and the adult and senile animals 60 min after administration of PGE2, the percent area occupied by large vacuolar bodies was significantly increased when compared to that of the young, adult and senile control animals, respectively. These findings suggest that the percent area occupied by large vacuolar bodies is increased in response to hypercalcemia induced by PGE2. It is thought that in the parathyroid glands suppressed by hypercalcemia there is a relationship between the percent area occupied by large vacuolar bodies and aging.

Aging↗

PubMed1994

[Reaction of the retina to injected subretinal fluids].

Experimental retinal detachment was produced by injecting various fluids into the subretinal space in pigmented rabbits. We selected autologous aqueous humor, autologous vitreous, and autoserum as substitutes for subretinal fluid. Retinal detachment disappeared within 24 hours. The eyes were enucleated 7 days after surgery for histopathological study. Destructive changes in photoreceptor layer occurred most severely when the eye was treated with serum. There was a decrease in the number of outer nuclear layer cells. Macrophages and fibroblastic cells had migrated into the subretinal space. Histopathological changes with vitreous were less pronounced than with serum. The cytoplasm of Mueller cells appeared to compensate for the loss of photoreceptor cells in the outer nuclear layer. Mild decrease in the number of photoreceptor cells was the sole pathological feature when the eye was treated with aqueous humor. The retina thus showed different reactions to the subretinal fluids of differing nature.

Animals↗

PubMed1993

Ultrastructure of the parathyroid gland of magnesium-treated golden hamster exposed to a hypergravity environment: a stereological study.

The ultrastructure of the parathyroid glands of magnesium-treated golden hamsters exposed to a 5 gravity environment was studied. In the parathyroid glands of the magnesium-treated animals exposed to a hypergravity environment, the Golgi complexes and cisternae of the granular endoplasmic reticulum were increased as compared to those of the magnesium-treated animals and decreased as compared to those of animals exposed to a hypergravity environment, but were almost the same as those of the control animals. In the control and experimental animals, the chief cells were rich in free ribosomes and mitochondria. In addition, numerous secretory granules were situated close to the plasma membrane in the magnesium-treated animals exposed to a hypergravity environment. These observations suggest that the synthesis of parathyroid hormone may be stimulated in the parathyroid glands of magnesium-treated hamsters exposed to hypergravity environment.

Animals↗

PubMed1993

Ultrastructural substrates for increased lung water content in experimental pulmonary edema.

We examined the relationship between the incidence of ultrastructural changes in the alveolar septum and the extravascular lung water content. Pulmonary edema was induced in 18 mongrel dogs by either dextran (n = 12) or alloxan (n = 6) administration. Six other dogs served as controls. Extravascular lung water content was measured by the thermal-dye double indicator dilution method. Specimens of lung tissue were examined with an electron microscope, and the incidence of 13 types of pathological changes in the alveolar septum was studied. For each type of pathological change, the incidence was correlated with the magnitude of lung water content. The following results were obtained. The incidence of edematous changes in the alveolar interstitium (widening of the interstitial space, and dispersion and disarray of collagen fibres in the interstitial space) was well correlated with lung water content (r = 0.78, p < 0.01, and r = 0.84, p < 0.01, respectively). The correlation was not significant in the remaining types of changes. We conclude that the incidence of the pathological changes in the alveolar septum is increased along with the increase in the content of lung water in both dextran- and alloxan-induced experimental pulmonary edema in dogs.

Alloxan↗

PubMed1993

[The parathyroid gland under normal and experimental conditions].

Since Sandström reported the first detailed description of the parathyroid glands of human beings in 1880, and Lever first described the ultrastructure of the parathyroid chief cells of rat in 1957, a large number of light and electron microscopic studies have been done on the parathyroid glands of numerous animal species under normal and experimental conditions. This review deals with the comparative morphology of the parathyroid glands in amphibians, reptiles, birds and mammals under normal conditions, and the problem concerning the effects of various experimental conditions on the parathyroid glands in mice, rabbits and hamsters. The parathyroid glands were recognized in all vertebrate animals higher than fish, and arose from the third and fourth branchial pouches. Several animals, such as the newt, lizard, gecko, mouse, rat, hamster and gerbil, had only two parathyroid glands, but most animals had four. In mammals, most of the parathyroid glands were closely associated with the thyroid gland, but in amphibians, reptiles and birds, the glands separated from the thyroid gland. In some mammals, the parenchymal cells of the parathyroid gland were classified under a light microscope into two main types of cells: chief cells and oxyphil cells. Examinations under an electron microscope also showed the chief cells having many cell organelles and the oxyphil cells filled with numerous mitochondria in the parathyroid glands of human beings, monkeys, cows, horses, bats and turtles. In addition, the chief cells in most animals were classified at the light microscopic level into light cells and dark cells, moreover the chief cells were also electron microscopically divided into a light and dark type showing different functional phases of a single cell type when osmium or glutaraldehyde fixative was used. However, it is widely accepted today that differences in cytoplasmic density of the chief cells are due to artifacts produced in the process of tissue preparation. The parenchymal cells of the parathyroid gland of the newt were divided into the basal cells (supporting cells) and the suprabasal cells (chief cells). In the parathyroid gland of the frog and toad, blood vessels and connective tissues were not present. In the parathyroid gland of the rabbit and hamster, the water-clear cell was observed. In the electron microscopic radioautograph of the parathyroid gland treated with 3H-leucine, most of the silver grains were seen over cisternae of the granular endoplasmic reticulum at 15 minutes, over the Golgi complexes at 30 minutes, and over secretory granules at 60 minutes.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗

PubMed1992

Pretreatment with catalase or dimethyl sulfoxide protects alloxan-induced acute lung edema in dogs.

We tested the preventive effects of catalase, an enzymatic scavenger of hydrogen peroxide, or dimethyl sulfoxide (DMSO), a hydroxyl radical scavenger, on intravenous alloxan-induced lung edema in four groups of pentobarbital sodium-anesthetized, ventilated dogs for 3 h: saline (20 ml.kg-1.h-1) infusion alone (n = 5), alloxan (75 mg/kg) + saline infusion (n = 5), catalase (150,000 U/kg) + alloxan + saline infusion (n = 5), or DMSO (4 mg/kg) + alloxan + saline infusion (n = 5). Catalase or DMSO significantly prevented the increase in plasma thromboxane B2 and 6-keto-prostaglandin F1 alpha over 3 h after alloxan and the accumulation of extravascular lung water after 3 h [3.95 +/- 0.52 (SE) g/g with catalase, 3.06 +/- 0.42 g/g with DMSO] but not early pulmonary arterial pressor response. An electron microscopic study indicated that catalase or DMSO significantly reduced the endothelial cellular damages after alloxan. These findings strongly suggest that hydrogen peroxide and hydroxyl radical are major mediators responsible for intravenous alloxan-induced edematous lung injury in anesthetized ventilated dogs.

6-Ketoprostaglandin F1 alpha↗