Survey and clinical application of serum iron, total iron binding capacity, transferrin saturation, and serum ferritin in captive black and white ruffed lemurs (Varecia variegata variegata).

Serum samples from 63 clinically normal captive black and white ruffed lemurs (Varecia variegata variegata) were analyzed to survey serum iron, total iron binding capacity, transferrin saturation, and serum ferritin levels. Data analysis showed no differences in these analytes attributable to sex, but significantly higher levels of serum iron, transferrin saturation, and serum ferritin in older animals. The survey data were examined in light of two black and white ruffed lemurs that were treated for iron overload with serial phlebotomies. Prior to therapy, both phlebotomized lemurs had excess hepatic iron deposition, but had serum iron, transferrin saturation, and serum ferritin below the upper limits observed in the survey animals, suggesting that some clinically normal animals included in the survey may have accumulated excess systemic iron. Serial phlebotomy therapy reduced serum iron, transferrin saturation, and serum ferritin in both animals. Three years after the conclusion of therapy in the one remaining case, serum iron and transferrin saturation have risen substantially, whereas serum ferritin has risen slightly. Serum iron, transferrin saturation, and serum ferritin may be useful predictors of systemic iron stores in this species, though the correlation between these parameters and systemic iron stores needs to be determined.     

Evaluation of iron status in lemurs by analysis of serum iron and ferritin concentrations, total iron-binding capacity, and transferrin saturation

OBJECTIVE: To assess serum iron and ferritin concentrations, total iron-binding capacity, and transferrin saturation as indicators of iron metabolic status in 3 genera of lemurs and determine whether these variables are useful for screening for iron overload. DESIGN: Cross-sectional study. ANIMALS: 11 ring-tailed lemurs (Lemur catta), 11 black lemurs (Eulemur macaco macaco), and 11 red-ruffed lemurs (Varecia rubra). PROCEDURES: Blood samples were collected weekly for 3 weeks and assayed for serum iron and ferritin concentrations and total iron-binding capacity. Liver biopsy specimens were evaluated histologically and assayed for total iron, nonheme iron, and trace mineral concentrations. Deposition of iron was scored on Prussian blue-stained slides. RESULTS: Hepatic iron content ranged from 497 to 12,800 Pg/g dry weight (median, 2,165 Pg/g). Differences were seen in mean hepatic iron content across genera, with ruffed lemurs having the highest concentrations and ring-tailed lemurs having the lowest. Iron accumulation in the liver was mild, and cellular pathologic changes associated with iron storage disease were not detected in any lemur. Ferritin concentration was the only variable that correlated significantly with hepatic iron content in all 3 genera of lemurs; however, both transferrin saturation and serum iron concentration were correlated with hepatic iron concentration in ring-tailed and ruffed lemurs. CONCLUSIONS AND CLINICAL RELEVANCE: Serum ferritin concentration was the only variable that was consistently correlated with hepatic iron content in all 3 genera. Mean hepatic iron content varied across genera, suggesting that the propensity for lemurs to develop iron overload in captivity may vary across taxa.     

Enzyme-linked immunosorbent assay for canine serum ferritin, using monoclonal anti-canine ferritin immunoglobulin G

Immunoassay of serum ferritin is currently used to evaluate the clinical iron status of human beings, horses, cattle, and swine. Because ferritins are immunologically species specific, a separate assay must be developed for each species. We have developed an ELISA for serum ferritin in dogs, using a monoclonal anti-canine ferritin antibody. Ferritin standards were linear (r = 0.997) from 0 to 80 ng/ml. Recovery of ferritin from canine serum was 94%. Dilutions of pooled canine serum were linear from 0 to 50% (r = 0.994). Within-assay coefficient of variability was 5.5%, whereas assay-to-assay coefficient of variability ranged from 12.5 to 21%. This assay should provide a nonsurgical means of accurately estimating dogs' iron stores.     

Relationship of serum ferritin and iron concentrations and serum total iron-binding capacity to nonheme iron stores in dogs

The relationships of various iron-related analytes were evaluated in 95 dogs. Liver and spleen nonheme iron content was determined coulometrically on acid-digested tissue specimens. Serum iron concentration and total iron-binding capacity also were measured coulometrically, whereas serum ferritin concentration was measured by ELISA. Significant (P less than 0.0002) correlation was found between serum ferritin concentration and nonheme iron stores. Significant correlation was not found between nonheme iron stores and serum iron concentration or total iron-binding capacity. Serum ferritin concentration should provide a convenient and relatively noninvasive means of estimating iron stores in dogs.     

Seroprevalence of Toxoplasma gondii, Sarcocystis neurona, and Encephalitozoon cuniculi in three species of lemurs from St. Catherines Island, GA, USA

In the current study, we determined the seroprevalence of Toxoplasma gondii, Sarcocystis neurona, and Encephalitozoon cuniculi in three species of lemurs from St. Catherines Island, Georgia. Serum samples were tested from 52 ring-tailed lemurs (Lemur catta), six blue-eyed black lemurs (Eulemur macaco flavifrons), and four black and white ruffed lemurs (Varecia variegata variegata) using an agglutination assay. Three ring-tailed lemurs (5.8%) were positive for T. gondii (titer of 1:50); one ring-tailed lemur (1.9%) and one black and white ruffed lemur (25%) were positive for S. neurona (titers of 1:1000); and one ring-tailed lemur (1.9%) was positive for E. cuniculi (titer of 1:400). All blue-eyed black lemurs were negative for antibodies to T. gondii, S. neurona, and E. cuniculi. This is the first detection of antibodies to T. gondii in ring-tailed lemurs and antibodies to S. neurona and E. cuniculi in any species of prosimian.     

Role of excessive maternal iron in the pathogenesis of congenital leukoencephalomalacia in captive black rhinoceroses (Diceros bicornis)

OBJECTIVE: To investigate the possibility that excessive maternal iron (overload) may contribute to development of congenital leukoencephalomalacia in captive black rhinoceroses. SAMPLE POPULATION: Tissue specimens and serum samples from 18 rhinoceroses in 2 kindreds harboring 4 (possibly 5) affected female calves. PROCEDURE: Fresh and archival sera and necropsy tissue specimens were evaluated to determine the nature and extent of iron overload in captive and wild black rhinoceroses as well as other rhinoceros species. RESULTS: Quantitative serum and tissue assays of iron and iron analytes, corroborated by histopathologic findings, indicated that these kindreds carried the greatest body burdens of iron yet found among captive black rhinoceroses. Fourteen of 18 rhinoceroses had the highest serum ferritin concentrations measured among 64 black rhinoceroses in captivity in the United States. Dams of affected calves had serum ferritin concentrations 2 orders of magnitude higher than clinically normal humans, equids, or free-ranging rhinoceroses. A neonatal serum sample from 1 affected female calf had a high ferritin concentration (approx 100-fold increase), but a male sibling of another affected female did not, suggesting a possible sex disparity in fetal response to maternal iron overload. Morphologic hallmarks of hemochromatosis were prominent in dams and grandams of affected calves. CONCLUSIONS AND CLINICAL RELEVANCE: Excessive maternal iron may affect female fetuses more than males, possibly inducing leukoencephalomalacia by catalyzing production of highly toxic hydroxyl free radicals during crucial periods of in utero development. Reduction of maternal iron overload may decrease the probability of developing leukoencephalomalacia and some other disorders commonly affecting rhinoceroses in captivity.     

FHC基因的结构与功能及其表达调控的研究进展

铁蛋白为机体内贮存铁的可溶性蛋白,人血清铁蛋白是机体含铁量的间接标记物,用于诊断缺铁性贫血。铁蛋白重链1(FHC)是铁蛋白的一种亚基,在氧化应激、病毒性肝炎、肿瘤细胞、视网膜的保护、少突胶质细胞的成熟、猪蓝耳病等方面具有重要调控作用。本文就FHC基因表达调控及生物学功能进行综述,以期为该基因作为动物抗病育种的遗传标记奠定基础,为免疫治疗、癌症预防与监控等研究提供参考。     

Iron content of rat serum ferritin.

The serum ferritin concentration was significantly higher in female than in male rats, reflecting higher iron stores in females than in males. The mean iron/protein ratio of serum ferritin was 0.018+/-0.008 (SD) (microg of Fe/microg of protein) in female rats and 0.011+/-0.011 in male rats, being much lower than that of liver ferritin (0.233+/-0.014 in females and 0.227+/-0.020 in males). Iron loading of rats significantly increased serum ferritin concentration, but did not influence the iron content of serum ferritin. These results indicate that rat serum ferritin contains only a small amount of iron independent of body iron stores.     

Yersinia enterocolitica infection in breeding colonies of ruffed lemurs

Two outbreaks of yersiniosis caused by Yersinia enterocolitica occurred in breeding colonies of red ruffed lemurs (Varecia variegata rubra) and black and white ruffed lemurs (Varecia variegata variegata) housed in outdoor enclosures during the winter breeding season and spring birth season, respectively. Seven of 11 animals at risk in the combined outbreaks became ill, and 3 died of acute to chronic infection. Clinical signs included anorexia, lethargy, diarrhea, abdominal pain, and hyperpyrexia. Necropsy findings included ulcerative enterocolitis and multifocal necrosis and abscess formation in mesenteric lymph nodes, liver, spleen, kidneys, and lungs. Histologically, lesions were characterized by necrotizing inflammation containing masses of basophilic bacteria. Yersinia enterocolitica serotype 0:2 was isolated from lesions. Neomycin sulfate given orally and chloramphenicol given intramuscularly were effective in treatment early in the course of the disease or in mild cases. In severe cases, lemurs did not respond to antibiotic and fluid therapy. Exposure to soil contaminated with infected rodent feces, stress, and behavioral factors in the ruffed lemur species are believed to have precipitated the infection.     

Effect of oral administration of excessive iron in adult ponies

OBJECTIVE: To evaluate the potential of excess dietary iron to cause hepatic lesions similar to those described in horses with suspected iron toxicosis or hemochromatosis. DESIGN: Prospective study. ANIMALS: 6 adult male ponies. PROCEDURE: 4 ponies received 50 mg of iron/kg (22.7 mg/lb) of body weight each day by oral administration of ferrous sulfate, which contained 20% elemental iron; 2 ponies received only the carrier (applesauce). Complete blood counts, serum biochemical analyses, and hepatic tissue biopsies were performed, and serum iron concentrations were measured. Blood and tissue samples were obtained at days 0 and 2, and at the end of weeks 1, 3, 6, and 8 after administration of iron was initiated. Treatment was discontinued after 8 weeks, and hepatic iron concentrations were measured at 28 weeks. RESULTS: Hepatic iron concentrations, serum iron concentrations, percentage saturation of transferrin, and serum ferritin concentrations were increased, compared with baseline and control concentrations, by week 8. Adverse clinical signs or histologic lesions in the liver were not detected in any ponies. At 28 weeks, hepatic iron concentrations had decreased. CONCLUSIONS AND CLINICAL RELEVANCE: Histologic lesions were not seen in the hepatic biopsy specimens obtained from the ponies treated with ferrous sulfate. It was concluded that it would be unlikely for iron toxicosis to develop in adult ponies or horses during a period of < 8 weeks when food or water contained increased amounts of iron. It is suspected that previous reports of hepatopathies in animals with hemosiderin accumulation may represent a primary hepatopathy with secondary hemosiderin accumulation, especially if the only source of iron is via oral consumption.     

Anthracycline cardiotoxicity in a black rhinoceros (Diceros bicornis): evidence for impaired antioxidant capacity compounded by iron overload

Two weeks before dying of congestive heart failure, a juvenile black rhinoceros (Diceros bicornis minor) received a single low dose of doxorubicin as part of combination chemotherapy for acute lymphoblastic leukemia. Diffuse hemosiderosis was present at necropsy in a pattern indicative of dietary iron overload, but unique iron-positive degenerative lesions were found in isolated myocardiocytes. Serum analyses revealed hyperferremia, 87% transferrin saturation, and 5- to 10-fold elevations in ferritin concentration, reflecting markedly increased tissue iron stores. Since both toxic and therapeutic effects of anthracyclines are mediated by formation of reactive free radicals via iron-catalyzed reactions, these observations suggest that iron overload may have enhanced myocardial susceptibility to cardiotoxic effects of doxorubicin. Impairments in other myocardial antioxidant defenses, such as deficiencies in catalase and glutathione S-transferase that are known to exist in rhinoceros erythrocytes, may have been underlying factors contributing to an inherent sensitivity of rhinoceros tissues to oxidant-induced injury.     

An improved ferritin assay for canine sera

An improved serum ferritin assay for canine serum has been developed. It uses two monoclonal antibodies in a sandwich arrangement. Serum ferritin can be determined on undiluted canine sera with this assay. The recovery of ferritin added to canine serum ranged from 98 to 106%, the within-assay coefficient of variability was 3.3 to 4.5%, and the assay-to-assay variability was 9.8 to 10.2%. Serum ferritin from 61 apparently healthy dogs had a geometric mean of 252 ng/ml, with a range of 80 ng/ml to 800 ng/ml.     

Effect of dietary iron content on hematologic and other measures of iron adequacy in dogs

Eighteen 9- to 10-week old Beagles were fed casein-based diets (4,710 kcal of metabolizable energy/kg of body weight) containing either 12, 80, or 160 mg of iron/kg of diet. Growth and feed consumption were monitored throughout the 47-day study. Hematocrit (Hct), hemoglobin (Hb) concentration, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), RBC numbers, erythrocyte protoporphyrin (EP) concentration, serum iron concentration, serum total iron-binding capacity (TIBC), and serum ferritin concentration were determined weekly. Growth rate and feed efficiency were not significantly influenced by dietary iron content. At 14 days, Hb concentration, Hct, MCV, MCH, RBC numbers, and serum iron concentration were significantly (P less than 0.05) lower in dogs fed the 12 mg/kg diet, and remained significantly low for the remainder of the study. Erythrocyte protoporphyrin concentration increased significantly (P less than 0.05) by 14 days in dogs fed the basal diet, and remained significantly high relative to that in dogs of the other dietary groups for the remainder of the study. Serum ferritin concentration decreased in dogs of the group fed the basal diet, with a significant (P less than 0.05) difference beyond day 42. Differences in Hct, MCH, MCV, or hemoglobin, serum iron, serum ferritin, or EP concentration were not found between groups fed 80 and 160 mg of iron/kg of diet. Liver nonheme iron content was significantly (P less than 0.05) affected by dietary iron content.     

铁蛋白纳米载体及其在生物医学领域的应用潜力

铁蛋白是广泛存在于几乎所有生命体中的储铁蛋白,具有储存和转化铁、维持细胞铁代谢平衡以及保护细胞免受氧化损伤等功能。铁蛋白亚基能够自组装成纳米笼,装载和运输各种金属、药物、显影剂等多种物质,并且铁蛋白具有易被修饰以及良好的生物相容性和靶向性等特点,使其成为生物医学领域应用潜力巨大的非病毒天然纳米材料。本文重点综述了铁蛋白的结构和生物学功能,以及基于铁蛋白搭建的纳米载体平台在疾病检测、纳米疫苗和药物载体等领域的研究进展及应用前景,旨在为基于铁蛋白纳米颗粒的相关研究提供参考。     

Camel Kidney Ferritin: Isolation and Partial Characterization

Camel kidney ferritin was isolated from a tissue homogenate by thermal denaturation, ammonium sulphate fractionation, Sephacryl S-300 gel filtration and DEAE-blue gel affinity chromatography. The yield and the iron and neutral carbohydrate contents were 0.012 mg/g wet tissue, 4.0% and 2.7%, respectively. The phosphate:iron ratio was 0.13, twofold lower than that reported for camel liver ferritin. Native gel electrophoresis revealed the presence of a monomeric ferritin. SDS gel electrophoresis and immunoblotting showed two types of subunits, heavy and light, contrary to the extensive heterogeneity observed in camel liver ferritin. In general, the tissue ferritins shared a similar amino acid composition. However, a twofold lower glycine and an eightfold higher arginine content were recorded for camel kidney ferritin. In addition, kidney ferritin had a relatively high content of glutamic acid. Cross-reactivity studies by Ouchterlony double diffusion and noncompetitive indirect ELISA revealed a distinct cross-reactivity between buffalo ferritin antiserum and camel liver ferritin, but camel liver ferritin showed only weak cross-reactivity.     

Change of Ferritin-binding Activity in the Serum of Foal after Birth

In mammal circulation, various ferritin-binding proteins (FBPs) are thought to be involved in the clearance of circulating ferritin after complex formation with it. However, horse FBPs are known to cause inhibitory effects on ferritin immunoassay due to the concealment of the ferritin molecule to anti-ferritin antibodies used in the ferritin immunoassay. These inhibitory effects are eliminated by heat treatment of horse serum at 75°C for 15 min. The inhibitory effects on ferritin immunoassay in the sera of ten foal sera (5 females and 5 males) from 1 to 18 months were detected during all periods, and ferritin concentrations of the foal sera increased 20–100% as compared with those of untreated sera by same heat treatment. Ferritin concentrations of heat-treated foal sera increased after birth, reaching to ferritin levels of adult horse at 9 months of age. Thereafter, although serum ferritin concentrations fell down at 12 months of age, these concentrations increased to adult levels at 15 months of age again. The ratio of ferritin concentration of heat-treated serum to that of the untreated serum was regarded as an apparent ferritin-binding activity. Ferritin-binding activities in the sera of foals showed peak at 2 and 4 months of age in females and males, respectively. These results suggested that horse FBPs were heat unstable, and FBPs may play an important role in iron metabolism at early developmental stage.     

Prevention of urethral blockage following semen collection in two species of lemur, Varecia variegata variegata and Lemur catta.

Lemurs are a diverse group of primates comprised of five families, all of which are found only on Madagascar and the Comoro Islands. Of the 60 known species, 17 are endangered and 5 of these are considered critically endangered. The effects of inbreeding on population health and viability have been well described; though negative inbreeding effects can be ameliorated through the introduction of new genetic material. Introduction of new individuals into a population can be extremely challenging because of the highly social nature of lemurs. Semen collection in lemur species is notoriously challenging, as the ejaculate forms a coagulum. During normal breeding, the coagulum forms a copulatory plug in the female. However, this coagulum can present a life-threatening situation when retained in the urethra abnormally following electroejaculation. This study investigates the use of ascorbic acid in preventing urethral blockage in two lemur species during semen collection, demonstrates successful collection of semen by electroejaculation from two species of lemur during the breeding season, and discusses removal of urethral plugs subsequent to semen collection. Semen was collected successfully from all animals. Urethral plugs formed during each collection and were abnormally retained in 2/11 collections. Both plugs were successfully and immediately removed with the use of retropulsion through a urethral catheter. Although the results of this study are encouraging, more investigation is required to establish whether or not this procedure can be safely performed in the field.     

Effect of infectious bursal disease virus insult on iron, copper, and zinc concentration in liver, bursa of Fabricius, spleen, pancreas, and serum of chickens

The effect of a systemic disease on the dynamics of iron, zinc, and copper in chickens fed ad libitum was examined by infecting 10-day-old specific pathogen-free chickens with infectious bursal disease virus (IBDV). Liver, bursa of Fabricius, pancreas, spleen, and serum were sampled in 10 controls and 10 challenged chickens at 3-day intervals postinfection (PI) for 15 days. The samples were analyzed using atomic absorption spectroscopy. Serum levels were similar to that reported in the literature. Concentrations of iron and zinc did not change significantly in the pancreas, but there was an increase in copper in infected pancreatic tissue on days 9 and 15 PI. Iron concentration in the spleen showed a significant increase on days 6, 9, and 15 PI, whereas zinc was only significantly increased on day 15 PI. There was no significant change in copper concentrations in the spleens of infected chickens vs. controls. This finding is in line with previously reported data. The results showed that the liver was not a major tissue where iron and zinc were sequestered, as previous data have shown in mammals. Instead, the bursa of Fabricius had significantly increased levels of both iron and zinc in infected tissue vs. control tissue from 9 days PI on. Furthermore, the bursa had increased levels of copper in the latter portion of the study. These findings suggest that the bursa of Fabricius rather than the liver is the major organ for metallic ion sequestering during IBDV infection.