Validation of a transendoscopic glandular and nonglandular gastric biopsy technique in horses.

REASONS FOR PERFORMING STUDY: In order to study the evolution of histopathological and immunohistochemical changes in the gastric mucosa of horses with EGUS (equine gastric ulcer syndrome), a feasible, useful, valid and safe in vivo gastric biopsy technique is required. OBJECTIVES: To determine the average gastric mucosal healing time following endoscopic gastric biopsy sampling, and evaluate the feasibility, safety and usefulness of samples obtained by this method for histopathological analysis. METHODS: Six mature mares from the Faculté de Médecine Vétérinaire research herd were used. Transendoscopic gastric biopsy was performed on Days 0 and 9 using a flexible forceps with oval and fenestrated jaws to obtain gastric mucosal samples from 4 different sites: cardia (C), fundus (F), margo plicatus (MP) and glandular mucosa (GL). A maximum of 4 samples per site was taken and processed routinely for histopathology, evaluated by a pathologist. On Days 1-4 and 9-11 the lesions created by the biopsies were evaluated by gastroscopy. Lesions were evaluated over time based on a score from 0-4, where 4 was the most severe. RESULTS: Biopsy samples could be obtained from all targeted sites except C. No abnormal clinical signs were observed up to 7 days post biopsy. The average biopsy lesion scores decreased significantly with time for all sites. The average lesion score was significantly higher for the MP compared to the other sites at Days 1 and 2. Samples taken from the nonglandular portion of the stomach were considered inadequate for histopathology, while those taken from the glandular mucosa were adequate. CONCLUSION: The transendoscopic gastric biopsy technique described here is a feasible, safe and useful technique for obtaining samples from the equine gastric glandular mucosa. Although biopsy samples could be obtained from several areas in the nonglandular mucosa, these were very small, took longer to heal and were not considered adequate for histopathological evaluation, and another technique should therefore be validated.

Risk assessment of cadmium toxicity on hepatic and renal tissues of rats.

Pollution and industrial practices result in concentrations of metals and other environmental agents that are related to environmental toxicity. A rat bioassay was utilized for the identification of toxic effects of cadmium intake. This demonstrated increased total urinary proteins and increased kidney weights in rats exposed to CdCl2 for 7 days, in drinking water (100 mg/L). Serum creatinine, total and direct bilirubin concentrations and alanine transaminase activity were increased in Cd-exposed rats, indicating renal and hepatic toxicity. It was also observed that lipoperoxide concentrations were increased, while Cu-Zn superoxide dismutase activity was decreased in rats treated with cadmium. This indicated that the renal and hepatic toxicity induced by cadmium involved superoxide radicals.

Toxic effects of alcohol intake on prostate of rats.

BACKGROUND: The present report was carried out to determine whether alcohol intake could induce prostate lesions. METHODS: We tested male rats for 300 days. Animals were divided into three groups: controls received only tap water as liquid diet; the chronic alcohol intake group received only ethanol solution in semivoluntary research; and the withdrawal group received the same treatment as chronic alcohol intake until 240 days, after which they reverted to drinking water. RESULTS: Chronic alcohol intake increased lipoperoxide concentrations and acid phosphatase activities. Cu-Zn superoxide dismutase (SOD) was decreased at 60 days, but approached controls values at 300 days following treatment. The serum increased alkaline phosphatase, and alanine transaminase activities reflected the chronic toxic effect of ethanol. CONCLUSIONS: Since SOD activity was unable to scavenge superoxide radical and lipoperoxide formation, we can conclude that superoxide is an important intermediate in prostate damage of chronic alcohol intake.

Toxicity of chronic ethanol ingestion and superoxide radical formation on seminal vesicle of rats.

The toxic effects of chronic ethanol ingestion were evaluated in male adult rats for 300 days. The animals were divided into three groups: the controls received only tap water as liquid diet; the chronic ethanol ingestion group received only ethanol solution (30%) in semivoluntary research; and the withdrawal group received the same treatment as chronic ethanol-treated rats until 240 days, after which they reverted to drinking water. Chronic ethanol ingestion induced increased lipoperoxide levels and acid phosphatase activities in seminal vesicles. Cu-Zn superoxide dismutase (SOD) decreased from its basal level 70.8 +/- 3.5 to 50.4 +/- 1.6 U/mg protein at 60 days of chronic ethanol ingestion. As changes in GSH-PX activity were observed in rats after chronic ethanol ingestion, while SOD activities were decreased in these animals, it is assumed that superoxide anion elicits lipoperoxide formation and induces cell damage before being converted to hydrogen peroxide by SOD. Ethanol withdrawal induced increased SOD activity and reduced seminal vesicle damage, indicating that the toxic effects were reversible, since increased SOD activity was adequate to scavenge superoxide radical formation. Superoxide radical is an important intermediate in the toxicity of chronic ethanol ingestion.

Superoxide radical and toxicity of environmental nickel exposure.

Three nickel compounds were tested for pancreatic, hepatic and osteogenic damage in rats by a single i.m. injection Ni++ (7 mg kg-1). The nickel induced biochemical alterations included significantly increased levels of serum alkaline phosphatase in rats with NiS (75%) and NiO (50%). Amylase and aspartate transaminase were also increased, and lipoperoxide was increased in rats with NiO (5.6-fold) and NiS (3.4-fold). No serum changes were observed with NiCl2. Daily injection of Cu-Zn superoxide dismutase (SOD) conjugated with polyethylene glycol prevented the serum level changes, indicating that superoxide radical is an important intermediate in toxicity of nickel insoluble compounds.

Toxic effects of water eutrophication on pancreatic, hepatic and osteogenic tissues of rats.

Pollution, industrial solvents, concentrations of metals and other environmental agents are widely related to biochemicals values which are used in disease diagnosis of environmental toxicity. A rat bioassay validated for the identification of toxic effects of eutrophication revealed increased serum activities of amylase, alanine transaminase (ALT) and alkaline phosphatase (ALP) in rats that received algae, filtered water and nickel or cadmium from drinking water. Serum Cu-Zn superoxide dismutase activity decreased from its basal level of 40.8 +/- 2.3 to 26.4 U/mg protein, at 7 days of algae and at 48 hr of nickel and cadmium water ingestion. The observation that lipoperoxide concentration was not altered in rats treated with filtered water, while amylase, ALT and ALP were increased in these rats and in those treated with nickel or cadmium, indicated that pancreatic, hepatic and osteogenic lesions by eutrophication were not related to superoxide radicals, and might be due to a novel toxic environmental agent found in filtered and non-filtered algae water.

Increased oxygen radical and high-dietary-carbohydrate pancreatic damage.

These data suggest that an improved understanding of the relationship between high dietary carbohydrate and the rate of lipid peroxidation may give some insight into possible treatment modalities for pancreatic damages and may shed light on molecular mechanisms underlying certain pathological processes. High dietary carbohydrate lesions are age related and induced alterations on ceruloplasmin, phospholipids, total proteins, copper and zinc serum levels. Significantly increased serum and pancreatic amylase, and lipoperoxide determinations were observed in 20 month old rats. Cu-Zn superoxide dismutase was decreased in these animals. Daily injection of Cu-Zn superoxide dismutase conjugated with polyethylene glycol (SOD-PEG) prevented the serum and pancreatic changes, indicating that superoxide radical is an important intermediate to high dietary carbohydrate lesion.

Clinical biochemical determinations in the Mangalarga-Paulista horse: reference values.

Biochemical values are widely related with environmental agents, sex and age, and are used in disease diagnosis. Numerous reports have been published on the biochemical parameters of different breeds of horses. However, there is a paucity of information concerning Cu-Zn superoxide dismutase (SOD), ceruloplasmin, copper and zinc determinations in the serum. Blood samples from a total of 60 horses of the Mangalarga-Paulista breed, representing three age groups (0 to 4 months old, 6 to 18 months old and adult) were examined. Male horses have a higher mean value of SOD, ceruloplasmin and copper than do females. No significant sex-related difference was observed in serum zinc content of weaned and adult horses. SOD activity was significantly higher in adult animals. Since SOD has a protective effect against superoxide free radical toxicity and possesses anti-inflammatory activity, it is reasonable to assume that the increased activity of this enzyme may be due to an adaptation mechanism which protects the adult animal against oxygen toxicity.

Protective effect of nickel chloride on superoxide damage: enhancement of CuZn superoxide dismutase affinity to the oxygen free radical.

The effect of nickel from soluble NiCl2 on Cu-Zn superoxide dismutase (SOD) activity, as well as on rate of nitro blue tetrazolium reduction, was studied in vitro since lipid peroxidation has been implicated in cell damage by nickel insoluble compounds, whose toxicity and carcinogenicity are well established. The physical and chemical nature of nickel compounds is one of the key determinations of its toxicity. Soluble nickel freely enter cells, but is just as readily excreted reducing the opportunity for production of lipid damage. Nickel from NiCl2 strongly activated SOD activity. In vitro addition of nickel chloride to a crude lung preparation altered the KM for SOD without changing the Vmax. Nickel chloride produced increased enzyme affinity to the substrate, because decreased (O2-) concentration that yields half-maximal velocity. The combination of nickel and SOD may contribute to stabilization of the particular conformation of SOD responsible for maximal catalytically activity.

High dietary carbohydrate and pancreatic lesion.

The ability of high dietary carbohydrate to induce acute pancreatitis was investigated in groups of 16, 21-day and 15-month old rats fed different carbohydrate diets for 30 days. Significantly increased levels of serum amylase (2-fold), phospholipids (50%), phosphorus (2-fold), and lipoperoxides (8-fold) were observed in 15-month old rats fed a high-carbohydrate diet, compared to rats fed a diet with normal carbohydrate levels, indicating peroxidation of membrane lipids which caused final cell death and pancreatic lesion. Serum Cu-Zn superoxide dismutase activity was not altered. Daily administration of bovine Cu-Zn superoxide dismutase conjugated with polyethylene glycol prevented the serum level alterations and pancreatic lesions, indicating that the superoxide radical has a role in dietary carbohydrate-induced acute pancreatitis. No biochemical changes were observed in rats in which treatment was initiated on the 21st day of life indicating that this is an age-related lesion.

High dietary carbohydrate and pancreatic lesion

The ability of high dietary carbohydrate to induce acute pancreatitis was investigated in groups of 16, 21-day and 15-month old rats fed different carbohydrate diets for 30 days. Significantly increased levels of serum amylase (2-fold), phospholipids (50 per cent ), phosphorus (2-fold), and lipoperoxides (8-fold) were observed in 15-month old rats fed a high-carbohydrate diet, compared to rats fed a diet with normal carbohydrate levels, indicating peroxidation of membrane lipids which caused final cell death and pancreatic lesion. Serum Cu-Zn superoxide dismutase activity was not altered. Daily administration of bovine Cu-Zn superoxide dismutase conjugated with polyethylene glycol prevented the serum level alterations and pancreatic lesions, indicating that the superoxide radical has a role in dietary carbohydrate-induced acute pancreatitis. No biochemical changes were observed in rats in which treatment was initiated on the 21st day of life indicating that this is an age-related lesion

Intratracheal injection of nickel chloride and copper-zinc superoxide dismutase activity in lung of rats.

Superoxide radical (O2-) is a free radical that may be involved in various toxic processes. Cu--Zn superoxide dismutase catalyses the dismutation of the superoxide free radical and protects cells from oxidative damage, and it has been used clinically. The concentration of Ni2+ and Cu--Zn superoxide dismutase activity were measured in lungs of rats at time intervals of 5, 12, 19, 26, 33, and 40 days following an intratracheal injection of 127 nmol of NiCl2. Nickel chloride increased nickel content and resulted in a significant increase of Cu--Zn superoxide dismutase activity in lungs. This elevation of Cu--Zn superoxide dismutase activity was highest on the 12th day (approximately threefold) and is at levels comparable to controls rats on day 40 onwards. Since Cu--Zn superoxide dismutase activity was increased in lung throughout our experimental period without corresponding increases of Cu2+ and Zn2+, we speculate that the elevation of Cu--Zn superoxide dismutase activity might be due to an increased half-life of the enzyme, induced by nickel.

Nickel chloride: potential accumulation from the airway. Toxicokinetics in rats.

The rate removal of nickel from the airway was measured in vivo. Removal in vivo was studied by intratracheal injection of nickel chloride solutions. Regardless of time after injection, the lungs and heart retained the greatest concentration of nickel and 40 days after 1.68 mumol administration they were the organs where nickel was still significantly measurable. The slow removal of nickel may indicate the presence of high affinity binding sites in the lung. Nickel can interact with others metals, such as copper and zinc, so that nickel exposure may have public health implications.

Pancreas damage and intratracheal NiCl2 administration. Effects of nickel chloride.

Changes in activities of Cu-Zn superoxide dismutase (SOD- E.C.1.15.1.1.) and lactate dehydrogenase (LDH- E.C.1.1.1.27.) and levels of copper, total protein, triglycerides, phospholipids and total lipids were investigated in pancreas of rats after intratracheal administration of NiCl2 (8.4 mumol/kg). Nickel chloride induced increased SOD activity in pancreas and erythrocytes. This elevation was related to increased copper and decreased phospholipid content in pancreas of these animals. In conclusion, the ability of an animal to tolerate nickel chloride induced damage was governed by a delicate balance between the generation of cytotoxic agents and the various pancreas defense capabilities.

Nickel chloride effects on erythrocyte generation of superoxide radical.

The superoxide anion (O2-) is an extremely potent free radical which is produced during the metabolism of aerobic living cells. (O2-) may be involved in lipid peroxidation reactions which occur in a variety of systems. Cu-Zn superoxide dismutase, a metalloprotein, catalyzes the dismutation of the superoxide free radical and protects cells against superoxide damage. The ability of NiCl2 to prevent lysis of erythrocytes was tested in rats. NiCl2 administered by intratracheal route prevented hemolysis and decreased total lipids, phospholipids and bilirubin in serum. The protective effect of NiCl2 was linked to an increase in the erythrocyte activity of superoxide dismutase.

Nickel chloride effects on erythrocyte generation of superoxide radical

The superoxide anion (O2) is an extremely potent free radical which is produced during the metabolism of aerobic linving cells. (O2) may be involved in lipid peroxidation reactions which occur in a variety of systems. Cu-Zn speroxide dimutase, a metalloprotein, catalyzes the dismutation of the superoxide free radical and protects cells aginst superoxide damage. The ability of NiCl2 to prevent lysis of erythrocytes was tested in rats. NiCl2 administered by intratracheal rouyte prevented hemolysis and decreased total lipids, phospholipids and bilirubin in serum. The protective effect of NiCl2 was linked to an increase in the erytrocyte activity of superoxide dismutase

Influence of nickel chloride on iron-deficiency in rats.

The present study was designed to investigate the effects of nickel chloride on dietary iron deficiency in rats. The degree of iron deficiency was relatively moderate, but a more generalized anemia occurred in iron deficiency, in absence of nickel chloride. Moderate iron deficiency anemia induced increased lactate-dehydrogenase activity of serum and bone marrow, perhaps related to the decreased production of energy by oxidative means. Nickel chloride, perhaps for its ability to change iron absorption, for the maintenance of bone marrow metabolism and for to increase ceruloplasmin activity, inhibited the alteration on hemoglobin synthesis. Furthermore, nickel chloride possibly for its action on copper content and Cu-Zn superoxide-dismutase activity, inhibits the shortening of the red cell life span, caused by superoxide radicals.

[Total proteins levels and embryonic development of eggs of sea urchins (Lytechinus variegatus) treated with YbCl3]. / Níveis de proteínas totais e o desenvolvimento embrionário de ovos de ouriço do mar (Lytechinus variegatus) tratados com YbCl3.

Total proteins levels and the embryonic development of sea urchin (Lytechinus variegatus) eggs treated with 25 micrograms/ml of YbCl3 in sea water for one hour were studied. After the treatment, eggs were let to develop for 24 hours when the total proteins levels were determined and morphological changes as well as the synchronism of the embryonic development have been checked.

Effect of nickel chloride on streptozotocin-induced diabetes in rats.

The potential of nickel chloride to prevent streptozotocin-induced hyperglycemia was tested in rats in vivo. To induce diabetes, streptozotocin (100 mg/kg body weight) was injected as a single dose. Streptozotocin treatment resulted in a significant decrease in plasma insulin and ceruloplasmin, and pancreatic Cu, protein, and Cu-Zn superoxide dismutase activity. In rats treated with nickel chloride (10 mg/kg body weight) and streptozotocin, these values were comparable with those observed in control rats. The results indicate that nickel chloride injected before streptozotocin prevented streptozotocin-induced hyperglycemia, and suggest that the protective effect was related to Cu-Zn superoxide dismutase activity, mediated by copper.