Effects of surfactants on glucosyltransferase production and in vitro sucrose-dependent colonization by Streptococcus mutans

OBJECTIVE: To study the distribution of myocardial structural elements in a univentricular experimental model (Halobatrachus didactylus) and the changes induced by acute exposure to a sublethal concentrations of cadmium. DESIGN: 15 specimens of H. didactylus (marine teleost) were divided in three groups: CTRL: the control group, the fish were injected with a saline solution; 24 H: 1 mg/kg of cadmium chloride was injected and fish were sacrificed after 1 day post injection; 7 D: fish where subjected to the same cadmium concentration and sacrificed after 7 days post injection. INTERVENTIONS: Histological sections (5 microns) of ventricle were coloured by PicroSirius method and used to determine the fraction area occupied by the several myocardium structural elements, using specific software Optimas Bioscan 5.2. MEASUREMENTS AND RESULTS: The different structural elements of H. didactylus myocardium displayed in different ways and its distribution along the ventricular wall remained unchanged on exposure to cadmium. The structural elements of H. didactylus myocardium showed a characteristic pattern: collagen type I revealed a heterogeneous distribution, with fractional area values greater in epicardial and endocardial layers; collagen type III, has a homogeneous distribution with the myocardial wall thickness with lesser fractional area values than collagen I; cardiac muscle tissue showed a tendency to occupy a greater fractional area in the epicardial-endocardial region. Cadmium toxicity resulted in an increase in the fractional area occupied by muscle tissue to the detriment of the area occupied by the intertrabecular spaces (lacunae), with no alterations in the other structural components. CONCLUSIONS: On our H. didactylus fish model, cadmium may have induced a myocardial edema which resulted in an increase in the fractional area occupied by muscle tissue, with no alterations in other structural components of the myocardium or in the relative ventricular mass.     

Myocardial distribution and biotransformation in vitro and in vivo of nicorandil in rats, with special reference to mitochondria

This study reports subcellular localization of nicorandil in the myocardium and metabolism in mitochondria after oral dosing of 3 mg/kg nicorandil to rats. In the in vitro experiments, nicorandil, which was incubated with tissue homogenates (liver, kidney, heart, and small intestine), was metabolized to its denitrated compound, SG-86, and unknown substances. In the absence of a NADPH-generating system in the heart, the metabolic activity existed only in the mitochondrial fraction, but not in cytosolic and microsomal fractions. In the presence of the system, the activity in the mitochondrial fraction became much higher. To examine subcellular distribution of nicorandil in the myocardium, [14C]nicorandil was orally given to rats. Fifteen minutes after oral dosing of 3 mg/kg [14C]nicorandil, of which myocardial concentration reached a peak, nicorandil and SG-86 were found in mitochondrial fractions as well as in cytosolic and microsomal ones of the heart. Electron-microscopic autoradiograms, 15 min after oral dosing of 3 mg/kg [3H]nicorandil to rats, also showed the existence of the silver grains (showing radioactivity) in mitochondria of the heart. We conclude that nicorandil given orally is distributed in mitochondria of the heart, being partly transformed into SG-86, and that the myocardial mitochondria may be a potential site of action of nicorandil, an opener of KATP channels, which have been demonstrated to be present in this subcellular particle.     

Distribution of nitrazepam and its metabolites in the subcellular fractions of several white rat organs

After intraperitoneal administration into rats at a dose of 100 mg per kg of body weight nitrazepame (mogadone, eunoktine) was enzymatically reduced with the subsequent acetylation. Derivatives of nitrazepame were found in cellular fragments and nuclei, in mitochondrial, microsomal and soluble fractions of liver, lungs, heart and brain tissues. Reduction of the substrate was shown to occur in soluble and microsomal fractions of liver tissue and acetylation--in mitochondria of lungs and liver tissue. Nitrazepame metabolites were quite uniformly distributed over cell organelles of heart and brain tissues; this suggests that they originate in the organs from other tissues, where the processes of reduction and acetylation take place. Nitrazepame and its derivatives penetrated into brain very effectively; this phenomenon is considered as an essential one for their pharmocological activity.     

Tissue residues of dietary cadmium in wood ducks

One-week-old wood ducks were fed cadmium in diets containing 18 or 30% protein for a period of three months. Seven drakes from each group were sacrificed, and blood, brain, muscle, kidney, liver, and wing feather tissues were collected and analyzed for cadmium. Highest cadmium concentrations were found in the kidney, liver, and feather tissues; blood, muscle, and brain cadmium residue levels were undetectable. Except in the kidney tissue, protein level of the diet did not affect cadmium residue levels. For birds that were changed to a cadmium-free, high-protein ration at 13 weeks of age, regression analysis indicated a significant decrease in cadmium residue levels for the kidney tissue only. Growth, as measured by bodyweight at 13 weeks of age, was not affected by the various cadmium treatment levels. Histopathological examination revealed lesions in the kidney tissues of the 100 ppm cadmium treatment groups, which were more severe in those birds receiving the 18% protein diet. Vacuolation of the pancreatic acinar cells was observed in all groups, but tended to occur more frequently in the higher cadmium level groups.     

Physical map of the Clostridium difficile chromosome

The present study was designed to investigate the effect of mercuric chloride administration on copper, zinc, and iron concentrations in the liver, kidney, lung, heart, spleen, and muscle of rats. The results showed that after dose and time exposure to mercuric chloride, the concentration of mercury in the six tissues was significantly elevated. Data showed that there were no interaction between mercury and tissue iron. There was a considerable elevation of the content of copper in the kidney and liver. The most significant changes in the copper concentration took place in the kidneys. About a twofold increase in the copper content of the kidney was noted after exposure to mercuric chloride (3 mg and 5 mg/kg). Only slight elevations in the copper content occurred in the liver especially in high dose and longer exposure time. In the remaining organs, the copper content was not changed significantly (p > 0.05). The most significant changes in the zinc concentration took place in liver, kidney, lung and heart (5 mg/kg). Marked changes in kidney zinc concentrations were observed at any of the specified doses. Zinc concentrations were significantly increased in kidney of rats sacrificed 9-48 h after s.c. injection of HgCl2 (5 mg/kg); in liver obtained from rats at 18, 24 or 48 h after injection; and in lung after 24 or 48 h of treatment. The heart and spleen zinc concentrations were elevated at 24 and 48 h after injection of HgCl2 (5 mg/kg), respectively. The results of this study implicate that effects on copper and zinc concentrations of the target tissues of mercury may play an important role in the pathogenesis of acute mercuric chloride intoxication.     

Amodal completion in the absence of image tangent discontinuities

The localization of the low-affinity adenosine binding protein adenotin-1 with respect to distribution in rat organs and subcellular compartments was investigated. Adenotin-1 was characterized by 5'-N-ethylcarboxamido[2,8-3H]adenosine ([3H]NECA) binding and Western blotting. Cytosolic as well as membrane fractions of all tissues contained adenotin-1. Highest levels of membrane-bound adenotin-1 were found in the liver (liver > kidney approximately spleen approximately lung > forebrain approximately cerebellum > fat heart - striated muscle), whereas highest levels of cytosolic adenotin-1 were detected in spleen, liver, lung and fat. Subcellular fractions from rat liver were prepared by differential and density gradient centrifugation. Like the homologous proteins endoplasmin or gp96, adenotin-1 is enriched in the endoplasmic reticulum. Cytosolic and membrane-bound adenotin-1 species are pharmacologically distinct, because in the liver particulate fraction adenotin-1 showed a more rapid binding kinetics, a twofold lower affinity for [3H]NECA (KD 227 nM vs. 105 nM) and a sevenfold higher affinity for 2-chloroadenosine than the cytosolic protein (Ki 1.48 microM vs. 9.25 microM). In rat liver cytosol, two different binding sites were found, which differed in [3H]NECA binding kinetics and displayed a hundredfold difference in their affinity for 2-chloro-5'-N-methylcarboxamidoadenosine (Ki 45.8 nM vs. 4.76 microM). The presence of adenotin-1 in subcellular fractions, as determined by radioligand binding, was confirmed by Western blotting. Adenotin-1 was detected as a 98-kDa band in all rat liver subcellular fractions, which agrees with the molecular mass determined for the purified protein. In the cytosol, a 65-kDa hand was labeled more intensely than the 98-kDa band. This additional band probably represents the pharmacologically distinct species of adenotin-1 found in the cytosol.     

Toluene-induced oxidative stress in several brain regions and other organs

The in vivo dose-response relationship between toluene and reactive oxygen species (ROS) formation in rat brain, liver, kidney, and lung, and the time-course of these effects has been characterized. The rate of oxygen radical formation was measured using the probe 2',7'-dichlorofluorescin diacetate. In vivo exposure to various doses of toluene (0.5, 1.0, and 1.5 g/kg ip) elicited a dose-dependent elevation of ROS generation within crude mitochondrial fractions obtained from rat lung and kidney, and within crude synaptosomal fractions from cerebellum. ROS formation in crude mitochondrial fractions from liver, and crude synaptosomal fractions from striatum and hippocampus, reached a maximum value at relatively low doses of toluene. Of the brain regions, the hippocampus had the highest induced levels of ROS. In vivo exposure to a single dose of toluene (1.5 g/kg ip), revealed that toluene-induced ROS reached a peak within 2 h, which correlated directly with measured toluene blood levels. This elevated oxidative activity was maintained throughout the next 24 h, even though blood values of toluene decreased to negligible amounts. These results demonstrate that exposure to toluene results in broad systemic elevation in the normal rate of oxygen radical generation, with such effects persisting in the tissues despite a rapid decline in toluene blood levels. Acute exposure to toluene may lead to extended ROS-related changes, and this may account for some of the clinical observations made in chronic toluene abusers.     

Mitochondrial aldehyde reductase: identification and characterization in rat liver and kidney cortex

Aldehyde reductase (EC 1.1.1.2) has been regarded so far as an exclusively cytosolic enzyme. The present investigation shows that mitochondria of rat liver, kidney cortex and, tentatively, heart also contain an enzyme catalyzing oxidation of NADPH by aldehydes, p-nitrobenzaldehyde, methylglyoxal and glyceraldehyde. Activity of the mitochondrial enzyme can only be measured after the organelles are disrupted by sonication or solubilized with nonionic detergents. Mitochondrial aldehyde reductase activity contributed to about 4.6% and 2.5% of the total cellular activity in liver and kidney cortex, respectively. However, the specific activity in liver mitochondria was about one third and in kidney cortex mitochondria one tenth of that in the cytosol of the corresponding organ. The mitochondrial enzyme resembled the cytosolic one by its absolute specificity towards NADPH as the electron donor, a similar profile of aldehydic electron acceptors and identical Km values. Mitochondrial aldehyde reductase differed from the cytosolic enzyme by low sensitivity to known inhibitors of cytosolic aldehyde reductase, AL-1576, AL-4114 and ONO-2235. In liver, about 60% of the mitochondrial activity was tightly bound to the membranes whereas about 40% was present in the mitochondrial matrix. The membrane-bound activity was inactivated by digestion of mitoplasts with trypsin, alpha-chymotrypsin or papain, thus pointing to exposition of the substrate-binding site at the external surface of the inner membrane. On the other hand, latency of the enzyme in intact mitochondria indicates that the NADPH-binding site is located at the inner surface. These data provide the first direct evidence for the existence of aldehyde reductase in mitochondria of some rat tissues.     

Heterogeneity of pituitary lactotrophs: immunocytochemical identification of functional subtypes

Phospholipase A2 (PLA2) has been demonstrated to play an important role in the reperfusion injury of the kidney, gut, brain, heart and pancreas. This study was carried out to clarify whether PLA2 was involved in the ischemia-reperfusion injury of the liver. Rats were anesthetized and underwent laparotomy. They were allocated into one of 4 groups, i.e., the groups of renal ischemia (group RI), renal control (group RC), hepatic ischemia (group HI), and hepatic control (group HC). In group RI, the left renal pedicle was occluded for 1 hr, and the left kidney was removed after 1-hr reperfusion. In group HI, the portal and the hepatic artery supplying the left and middle lobes were clamped for 1 hr, followed by reperfusion. After predetermined periods of reperfusion up to 24 hr, the ischemic lobes were removed, homogenized and centrifuged. PLA2 activities in the mitochondrial fraction and the cytosolic fraction were measured with 14C-phosphatidylcholine (PC) and 14C-phosphatidylethanolamine (PE) as exogenous substrates. PLA2 activities of the both fractions in the kidney were significantly enhanced after 1-hr ischemia followed by 1-hr reperfusion. However, there was no enhancement of PLA2 activity of the either fraction in the group HI compared with the group HC. The results indicate that PLA2 is activated in the kidney but not in the liver during ischemia-reperfusion.     

Tissue- and subcellular-distribution of the binding site of [3H]9- methyl-7-bromoeudistomin D, a potent caffeine-like Ca2+ releaser, in rabbits

Tissue and subcellular distribution of the binding site of 3H-labelled 9-methyl-7-bromoeudistomin D ([3H]MBED), a powerful caffeine-like Ca2+ releaser, were investigated in rabbits. The order of specific activities of total homogenates was liver > brain > other tissues. All binding was completely suppressed by 10 mM caffeine, indicating that all [3H]MBED binding sites are modulated by caffeine. [3H]MBED binding sites distributed mainly in membrane fractions rather than soluble fractions in most tissues. In lung and liver, [3H]MBED binding was enriched in microsomes. [3H]MBED may be useful as a probe to investigate the actions of caffeine at the molecular level not only in muscles but also in a variety of tissues including liver, kidney and lung.     

Effects of chloroquine treatment on antioxidant enzymes in rat liver and kidney

The effect of chloroquine (CHQ) administration on antioxidant enzymes in rat liver and kidney was studied. Male Sprague-Dawley rats were administered 20 mg/kg CHQ once a week for 4 weeks (chronic treatment) or a single dose at 10 or 20 mg/kg (acute treatment). Antioxidant enzyme activities were determined in cytosolic fractions of liver and kidney, whereas reduced glutathione (GSH) and malondialdehyde (MDA) were determined in tissue samples. Results indicate minimal effects of acute CHQ treatment, whereas chronic treatment with CHQ differentially affected antioxidant enzymes in the two organs. Superoxide dismutase activity was increased nearly twofold, while activities of selenium glutathione peroxidase (GPX), catalase, and NAD (P) H: quinone oxidoreductase were decreased in livers of CHQ-treated rats compared to controls. No significant effects of CHQ on glutathione reductase, GSH, and MDA levels were seen in the liver. Fewer effects of CHQ were observed in the kidney where a decrease in GPX activity and an increase in MDA levels was seen. Lowering of antioxidant enzymes activities in the liver by CHQ could render the organ more susceptible to subsequent oxidative stress; while increased MDA production after CHQ treatment in the kidney indicate that the organ is being subjected to oxidative stress. This could have implications for prolonged chloroquine intake.     

Cytochrome P450 2E1 activity in diabetic and obese patients as assessed by chlorzoxazone hydroxylation

We have previously reported that theophylline administration (100 mg/kg bw/day) changes the levels of carnitine in the plasma and tissues of rats. The objective of this study was to investigate the effect of theophylline treatment on the activity of carnitine acetyltransferase (CAT) in rat kidney. CAT catalyzes the reversible transfer of short-chain acyl groups across the inner mitochodrial membrane. Results showed that a significant increase in the activity of CAT was observed in kidney theophylline-treated groups as compared to either control or placebo groups (P < 0.01). The ratio of total carnitine (TC) levels to CAT activity was significantly increased in theophylline-treated rats as compared to either control or placebo groups (P < 0.01). Moreover, the results showed a positive correlation between the kidney TC and CAT activity (P < 0.01), whereas they showed a positive correlation between plasma levels of TC and kidney levels of TC (P < 0.01). These changes in activity CAT as well as TC levels might be due to the result from theophylline-enhanced mobilization of lipid from adipose tissues which consequently stimulated an increased carnitine transport into the kidney tissues to form fatty acyl-carnitine groups for subsequent beta-oxidation inside the mitochondria.     

Cadmium toxicity and distribution in metallothionein-I and -II deficient transgenic mice

To date, numerous correlative studies have implicated metallothionein in the detoxification of heavy metals and in the regulation of metal distribution within an organism. In the present study cadmium-binding proteins (metallothionein equivalents), cadmium acute toxicity, and cadmium distribution in tissues and subcellular fractions were compared in metallothionein-I and -II deficient (MT-/-) mice and the parental strain carrying intact metallothionein genes (MT+/+) to determine if the absence of metallothionein altered any of these parameters. In an uninduced state, MT-/- mice expressed lower levels of cadmium-binding proteins relative to MT+/+ mice in several tissues. Administration of zinc enhanced the levels of cadmium-binding proteins in liver, small intestine, kidney, pancreas, and male sex organs, but not in cecum or brain of MT+/+ mice compared to zinc pretreated MT-/- mice. The cadmium LD50 was similar for MT-/-, MT+/+, and zinc-pretreated MT-/- mice (15-17 mumol CdCl2/kg body weight delivered i.p.). However, zinc-pretreated MT+/+ mice had a cadmium LD50 of 58-63 mumol CdCl2/kg body weight. Over two-thirds of cadmium was found in liver, cecum, small intestine, and kidney in both MT+/+ and MT-/- mice; therefore, metallothionein levels do not appear to play a major role in the tissue distribution of cadmium. However, after zinc pretreatment, MT+/+ mice accumulated more cadmium in the liver and less in other tissues, whereas the amount of cadmium in the liver was not altered by zinc pretreatment in MT-/- mice. In general, the cytosolic/particulate ratio of cadmium was significantly higher in tissues of noninduced MT+/+ mice relative to MT-/- mice. This difference was accentuated after zinc pretreatment. Together these results indicate that basal levels of metallothionein do not protect from the acute toxicity of a single i.p. cadmium challenge. Furthermore, it does not appear that the cytosolic compartmentalization of cadmium is correlated with reduced toxicity.     

Alterations of antioxidant enzymes and oxidative damage to macromolecules in different organs of rats during aging

Oxygen free radicals have been hypothesized to play an important role in the aging process. To investigate the correlation between the oxidative stress and aging, we have determined the levels of oxidative protein damage and lipid peroxidation in the brain and liver, and activities of antioxidant enzymes in the brain, liver, heart, kidney, and serum from the Fisher 344 rats at ages of 1, 6, 12, 18, and 24 months. The results showed that the level of oxidative protein damage (measured as carbonyl content) in the brain and liver was significantly higher in older animals than in young animals. No statistical difference was observed in the lipid peroxidation of the liver and brain between young and old animals. The activities of antioxidant enzymes in most tissues displayed an age-dependent decline. Superoxide dismutases in the heart, kidney, and serum, glutathione peroxidase activities in the serum and kidney, and catalase activities in the brain, liver, and kidney, significantly decreased during aging. Cytochrome c oxidase, an enzyme involved in electron transport in mitochondria, initially increased, but subsequently decreased in the aged brain, whereas no significant alteration was observed in the liver mitochondrial antioxidant enzymes. The present studies suggest that the accumulation of oxidized proteins during aging is most likely to be linked with an age-related decline of antioxidant enzyme activities, whereas lipid peroxidation is less sensitive to predict the aging process.     

Endoscopic treatment of vesicorenal reflux in children. Five-year assessment of the use of Macroplastique

Cadmium, unlike zinc, selenium and copper, has no known biological importance, and therefore, it is classified as a carcinogen in humans, as well as in animals. The effect(s) of levels of dermally-administered cadmium on cadmium genotoxicity and cytotoxicity was investigated in Harlan Sprague-Dawley rats for 14, 21, 28, 35 and 42 days at concentrations of 14 and 28 mg/kg/day. Exposure of rats to cadmium via dermal application caused lesions on the skin (hyperkeratosis, acanthosis and scabbing, alopecia and erythema) and tumors in the scrotum. Anatomical changes, such as distention of the stomach, atrophy of kidney and liver and loss of body weight were also observed in these rats. The toxic effects of cadmium on cell ultrastructure were nuclear membrane damage, chromatin condensation, regression of mitochondrial cristae and ultimately cell death. Analyses of the brain, kidney and liver cells of rats exposed to cadmium, clearly showed DNA damage. Of the three organs examined, DNA from kidney cells sustained the most damage followed by DNA in liver cells. There is a positive correlation between Cd dose(s) and duration of exposure and the extent of DNA damage.     

Relative concentrations of heavy metals in the parasites Ascaris suum (Nematoda) and Fasciola hepatica (Digenea) and their respective porcine and bovine definitive hosts

The concentrations of lead and cadmium determined by electrothermal atomic absorption spectrometry were significantly higher in the liver and kidney, respectively, of pigs than in their intestinal nematode parasites Ascaris suum. There was no clear pattern in the distribution of lead within the ascarids, but cadmium concentrations were highest in the intestine. A parallel investigation of cattle naturally infected with the liver fluke, Fasciola hepatica, revealed interesting differences. Although the cadmium content of F. hepatica was considerably lower than that in the tissues of cattle, the concentration of lead in the digenean was on average 172, 53 and 115 times higher than in the muscle, kidney and liver of the host. Furthermore, there was a significant positive correlation between the weight of individual F. hepatica and their lead burden. The lack of appreciable heavy-metal accumulation in A. suum is consistent with results for the nematode Anguillicola crassus in fish. However, although lead concentrations in the liver fluke F. hepatica were considerably elevated above host tissue levels, the degree of heavy-metal accumulation was relatively low when compared to that of acanthocephalans and cestodes of fish.     

Superoxide production and antioxidant enzymes in ammonia intoxication in rats

Injection of large doses of ammonium salts lead to the rapid death of animals. However, the molecular mechanisms involved in ammonia toxicity remain to be clarified. We have tested the effect of injecting 7 mmol/kg of ammonium acetate on the production of superoxide and on the activities of some antioxidant enzymes in rat liver, brain, erythrocytes and plasma. Glutathione peroxidase, superoxide dismutase and catalase activities were decreased in liver and brain (both in cytosolic and mitochondrial fractions) and also in blood red cells, while glutathione reductase activity remained unchanged. Superoxide production in submitochondrial particles from liver and brain was increased by more than 100% in both tissues. Both diminished activity of antioxidant enzymes and increased superoxide radical production could lead to oxidative stress and cell damage, which could be involved in the mechanism of acute ammonia toxicity.     

Change in lipid composition and lipid peroxidation rate in brain tissue under conditions of thymic hormone deficiency

Experiments on mature male rats have shown that 3 and 6 months after removal of the brain thymus, the level of total lipids in all cell centrifugate fractions (homogenate, supramitochondrial and mitochondrial fractions), which was followed by the higher rate of lipid peroxidation and the lower activity of cellular compartments, the spectrum imbalance of lipid fractions with predominant increases in the levels of phospholipids and free cholesterol. It is suggested that these changes make a contribution to the dysfunction of brain structures and participate in regulatory processes in thymectomy.