Red Blood Cell Enzyme Research Articles

An alternative model for heme biosynthesis in the malarial parasite

The malarial parasite imports an infected host's red blood cell enzymes for heme biosynthesis during the intraerythrocytic stage. This is despite all the genes of the heme-biosynthetic pathway having been identified on the parasite genome. On the basis of predictions of parasite genome-coded enzyme localization, functionality of some of these enzymes and shuttling of intermediates between different parasite compartments, a hybrid model for parasite heme biosynthesis has been proposed. However, this model does not take into account the possible role of imported host enzymes in parasite heme biosynthesis. We propose an alternative model with an extrinsic heme-biosynthetic pathway in the parasite cytosol that uses imported host enzymes, and an intrinsic pathway confined to the organellar fractions that uses the parasite-genome-encoded enzymes.

Pyruvate kinase deficiency

Over the past few years the inherited disorders of erythrocyte metabolism have been the object of intensive research which has resulted in a better understanding of their molecular basis. However, curative therapy for red blood cell (RBC) enzyme defects still remains undeveloped. Among glycolytic

Indian herbs result in hypoglycemic responses in streptozotocin-induced diabetic rats

Abstract The main aim of this study was to evaluate the protective effect of selected Indian herbal hypoglycemic agents on oxidative stress and antioxidant status in streptozotocin-induced diabetic rats. Oral administration of aqueous extracts of Momordica charantia , Allium sativum , Azadirachta indica , and Ocimum sanctum led to marked lowering of blood sugar level in diabetic rats. Free radical–induced lipid peroxidation is associated with numerous disease processes, including diabetes mellitus. Our results revealed an increased level of plasma lipid peroxide associated with diminution of the corresponding antioxidant enzymes in red blood cells, namely, catalase, glutathione reductase, glutathione peroxidase, and superoxide dismutase after marked depletion of glutathione in diabetic rats. Treatment with herbal hypoglycemic agents, that is, M charantia , A sativum , A indica , and O sanctum , not only inhibited the process of lipid peroxidation but also significantly reactivated the antioxidant enzymes and restored glutathione levels in the rat model. We conclude that the herbal plants tested possess both antidiabetic and antioxidative activities and that their proper use in diet may help decrease the oxidative load in diabetes mellitus. Furthermore, these herbs might help in minimizing diabetic-related complications such as diabetic retinopathy, neuropathy, and nephropathy.

50th Anniversary of Artificial Cells: Their Role in Biotechnology, Nanomedicine, Regenerative Medicine, Blood Substitutes, Bioencapsulation, Cell/Stem Cell Therapy and Nanorobotics

It was 50 years ago that the first “artificial cells” were prepared [1,2]. This was not an attempt to reproduce biological cells, but to use available basic knowledge to prepare simple systems for possible uses in medicine and other areas. The 1957 emulsion method for forming ultrathin polymeric membrane artificial cells containing hemoglobin and red blood cell enzymes (Figure 1) has become the basis for the preparation of other types of microscopic and nanodimension artificial cells. Extensions of the original 1957 drop procedure for forming larger artificial cells (Figure 1) have become the basis for preparing artificial cells to contain islet, hepatocytes, genetic engineered cells, stem cells and other types of cells. Figure 1 Original 1957 method of preparing artificial cells (for details see [1,5]). Upper: drop method for preparing large artificial cells. Principle later extended for use in bioencapsulation of cells, stem cells, genetic engineered cells. Lower: emulsion phase ... There have been increasing and recently explosive interest and research activities around the world on artificial cells, especially in fields related to biotechnology, nanomedicine, nanoscience, bioencapsulation, cell therapy, blood substitutes, advance drug delivery systems, and even nanoscale robotics and others (Table 1). However, instead of the term “artificial cells,” many use other terminologies, such as liposomes, nanoparticles, microcapsules, blood substitutes, bioencapsulation, and so on. Table 1 Examples of areas of application (details in [4,5] As a result, any meaningful literature search for a complete idea of the present status of the whole field of artificial cells is impossible. Furthermore, the fact that papers in this highly interdisciplinary area are published in numerous journals specializing in chemistry, medicine, surgery, bioengineering, nanoscience and others makes a literature search even more difficult. Books in this area are mostly multi-authored, describing very specific and narrow areas. Thus for the 50th anniversary of artificial cells the author has just prepared a monograph on ARTIFICIAL CELLS: Biotechnology, Nanomedicine, Regenerative Medicine, Blood Substitutes and Cell/Stem Cell Therapy [5]. This is now such a large area that it needed more than 1000 references just to summarize the present status and future perspectives of artificial cells.

Effect of melatonin on enzyme activities of glutathione reductase from human erythrocytes in vitro and from rat erythrocytes in vivo

The in vivo and in vitro effects of melatonin on enzyme activity of glutathione reductase (Glutathione: NADP(+) oxidoreductase, EC 1.8.1.7; GR) were investigated in this study. Glutathione reductase was purified from human erythrocytes 5.823-fold with a yield of 24% by ammonium sulfate fractionation, affinity chromatography on 2',5'-ADP Sepharose 4B and gel filtration chromatography on Sephadex G-200. Enzyme activity was determined by the Calberg and Mannervik method using a spectrophotometer at 340 nm. For in vitro experiments, the enzyme activity increased at 0.02 mM and decreased at 0.08 mM melatonin concentration and reached a plateau above 0.08 mM. Melatonin was administered 10 mg/kg intraperitoneally (ip) and had a stimulatory effect on the enzyme. In vivo studies were performed for melatonin in Sprague-Dawley rats and time-dependent effects were demonstrated. Glutathione reductase activity in erythrocytes was increased more by melatonin at 1 and 3 h. These results indicate that pharmacological levels of melatonin increased enzyme activity in erythrocytes. They also indicate that melatonin may be pharmacologically useful in patients with a deficiency of the enzyme in red blood cells causing hemolytic anemia.

Glucose-6-phosphate-dehydrogenase is also increased in erythrocytes from adolescents with Down syndrome

For some time it has been claimed that trisomic cells are more sensitive to oxidative stress since there is an imbalance in hydrogen peroxide metabolism due to an increase in superoxide dismutase (SOD) catalytic activity. We designed the present study to assess activity levels of antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glucose-6-phosphate-dehydrogenase (G6PDH)] in erythrocytes in 31 male adolescents with Down syndrome (mean age 16.3 +/- 1.1). An increase of 35.2%, 15.3% and 14.9% in the catalytic activity of SOD, GPx and G6PDH respectively was observed in male adolescents with Down syndrome compared to age-matched controls. For CAT, a slight increase of 6.0% was also found. It is concluded that our data are consistent with previous evidence of the existence of oxidative stress in individuals with Down syndrome as revealed by significantly enhanced activities of SOD and GPx. The most striking feature was that G6PDH, in contrast to CAT, presented a similar behaviour. Further studies are required to identify other antioxidant enzymes in red blood cells as well as in white blood cells in order to increase the range of potential bioindicators of oxidative stress.

Regulation of human erythrocyte metabolism by insulin: Cellular distribution of 6-phosphofructo-1-kinase and its implication for red blood cell function

Human erythrocytes are highly specialized cells whose function is oxygen transport. These cells’ sole metabolic source of energy is the fermentation of glucose via glycolysis. They contain an active insulin receptor and respond to insulin by increasing phosphorylation of tyrosine residues in several proteins. However, no metabolic effects have yet been associated with activation of this receptor in human erythrocytes. Here, we show that insulin increases the rate of glycolysis in human erythrocytes. Lactate production increased 56 and 173% in the presence of 10 and 100 nM insulin, respectively. A higher insulin concentration (1000 nM) partially reversed the stimulation of glycolysis. These effects occur through activation of the key glycolytic enzyme 6-phosphofructo-1-kinase, which exhibits the same pattern of modulation by insulin as seen for glycolytic flux. This modulation also occurs physiologically since ex vivo experiments revealed 50% stimulation of 6-phosphofructo-1-kinase (PFK) activity following a high carbohydrate meal. Insulin increases phosphorylation of PFK and redistributes the enzyme in red blood cells, causing it to detach from the erythrocyte membrane: upon insulin stimulation, the amount of enzyme associated with the plasma decreases by 86%. Detachment is a common mechanism of enzyme activation. As a consequence, insulin prevents up to 68% of red cells hemolysis. These results show that insulin regulates erythrocyte glycolysis and viability and suggest that this regulation is associated to other erythrocyte functions such as oxygen transport. Finally, we suggest that this regulatory mechanism might be compromised in patients with diabetes mellitus.

Total arterial revascularisation: effect of avoiding cardiopulmonary bypass on in-hospital mortality and morbidity in a propensity-matched cohort

The combination of total arterial revascularisation and avoidance of cardiopulmonary bypass may provide additional benefits to patients receiving complete arterial grafting with cardiopulmonary bypass. We performed a propensity-matched cohort study of complete arterial off-pump and on-pump coronary surgery and examined differences in in-hospital mortality and morbidity. Three hundred and sixty patients who underwent off-pump coronary surgery with complete arterial grafting between April 1997 and September 2002 were matched to 360 patients who received coronary surgery with cardiopulmonary bypass and complete arterial grafting. To match off-pump with unique on-pump patients, logistic regression was used to develop a propensity score for off-pump surgery. The C statistic for this model was 0.79. Off-pump patients were matched to unique on-pump patients with an identical 5-digit propensity score. If this could not be done, we then proceeded to a 4-, 3-, 2-, or 1-digit match. Patient characteristics were well matched. There was no difference in in-hospital mortality between the groups. Off-pump patients were less likely to develop sternal wound infections compared to the on-pump group (2.5 versus 5.8%; P=0.03), and had significantly lower blood loss (675 versus 780 ml; P<0.001), red blood cell unit transfusion (8.6 versus 38.9%; P<0.001), enzyme rises (13 versus 23 U/l; P<0.001), inotrope support (11.9 versus 28.9%; P<0.001), and ventilation times (5 versus 8 h; P<0.001). Intensive care unit and hospital stay were also significantly lower in the off-pump patients. Off-pump coronary surgery with complete arterial revascularisation can significantly reduce in-hospital morbidity and lengths of stay compared to conventional on-pump coronary surgery.

The effects of hormone replacement therapy combined with vitamins C and E on antioxidants levels and lipid profiles in postmenopausal women with Type 2 diabetes*1

Background: Recent studies have demonstrated that oxidative modification of low-density lipoprotein (LDL) involving the formation of lipid peroxides (MDA), exerts several biological effects that may contribute to the onset and progression of cardiovascular diseases in postmenopausal women with Type 2 diabetes (DPMW). Therefore, the aim of our study was to evaluate the effect of hormone replacement therapy (HRT), vitamin C and E (VCE) treatments on lipid profiles, glucose and MDA levels as well as antioxidant vitamins and enzymes in plasma and red blood cells (RBC) in diabetic or non-diabetic postmenopausal women (PMW). Methods: Oral HRT and VCE supplementation for 6 weeks were compared with HRT treatment in 40 non-diabetic PMW and 40 DPMW. Results: In the 40 postmenopausal women (PMW) and 20 postmenopausal women with DPMW who received oral HRT and 20 DPMW who received HRT plus VCE, there was a significant fall in MDA, total cholesterol, LDL-cholesterol and triglyceride values. Glycated haemoglobin (HbA1c) in the DPMW was significantly improved with oral HRT and VCE although no significant change in white blood cell counts, vitamin A and HDL values occurred. Additionally, a fall in plasma glucose, HbA1c and platelet values also occurred in the PMW and DPMW groups by oral HRT and VCE treatments. There was a significant increase in plasma vitamin E and beta-carotene concentrations, catalase, glutathione peroxidase and reduced glutathione levels in RBC and plasma in DPMW by treatments with HRT and/or VCE. Conclusions: Daily VCE and HRT administrations both in PMW and DPMW seem to produce significant improvement in antioxidants concentrations, and the metabolic control of lipids and glucose. The HRT and VCE supplementations may strengthen the antioxidant defense system due to reducing blood glucose and lipid metabolites, and they may play a role in preventing cardiovascular diseases in postmenopausal women with Type 2 diabetes.

The effects of hormone replacement therapy combined with vitamins C and E on antioxidants levels and lipid profiles in postmenopausal women with Type 2 diabetes

Background: Recent studies have demonstrated that oxidative modification of low-density lipoprotein (LDL) involving the formation of lipid peroxides (MDA), exerts several biological effects that may contribute to the onset and progression of cardiovascular diseases in postmenopausal women with Type 2 diabetes (DPMW). Therefore, the aim of our study was to evaluate the effect of hormone replacement therapy (HRT), vitamin C and E (VCE) treatments on lipid profiles, glucose and MDA levels as well as antioxidant vitamins and enzymes in plasma and red blood cells (RBC) in diabetic or non-diabetic postmenopausal women (PMW). Methods: Oral HRT and VCE supplementation for 6 weeks were compared with HRT treatment in 40 non-diabetic PMW and 40 DPMW. Results: In the 40 postmenopausal women (PMW) and 20 postmenopausal women with DPMW who received oral HRT and 20 DPMW who received HRT plus VCE, there was a significant fall in MDA, total cholesterol, LDL-cholesterol and triglyceride values. Glycated haemoglobin (HbA1c) in the DPMW was significantly improved with oral HRT and VCE although no significant change in white blood cell counts, vitamin A and HDL values occurred. Additionally, a fall in plasma glucose, HbA1c and platelet values also occurred in the PMW and DPMW groups by oral HRT and VCE treatments. There was a significant increase in plasma vitamin E and beta-carotene concentrations, catalase, glutathione peroxidase and reduced glutathione levels in RBC and plasma in DPMW by treatments with HRT and/or VCE. Conclusions: Daily VCE and HRT administrations both in PMW and DPMW seem to produce significant improvement in antioxidants concentrations, and the metabolic control of lipids and glucose. The HRT and VCE supplementations may strengthen the antioxidant defense system due to reducing blood glucose and lipid metabolites, and they may play a role in preventing cardiovascular diseases in postmenopausal women with Type 2 diabetes.

Role of haemoglobin in the protection of cultured lymphocytes against diepoxybutane (DEB), assessed by in vitro induced chromosome breakage

Diepoxybutane (DEB) is an alkylating agent that can be used to assess chromosome instability in repair-deficient subjects. Previous authors investigated the role of red blood cells (RBC) in determining individual susceptibility to DEB in normal healthy donors, and demonstrated that a polymorphic enzyme in RBC, Glutathione S-transferase T1 (GSTT1), is involved in DEB detoxification. In the present work we studied the influence of individual GSTM1 and GSTT1 genotypes and the presence of RBC on the frequency of DEB-induced chromosome breakage in lymphocyte cultures from normal individuals and, in particular, the influence of isolated components of RBC: RBC membranes, RBC lysate, and haemoglobin. Our results confirm that individual GSTT1 genotypes modulate the level of genetic lesions induced by DEB; however, this effect was not sufficient to explain the highly significant variation in chromosome breakage between whole blood and RBC-depleted cultures. We showed that RBC can protect cultured lymphocytes against chromosome breakage induced by DEB and we demonstrated the particular role of haemoglobin in the protective effect.

Effects of Commonly Consumed Fruit Juices and Carbohydrates on Redox Status and Anticancer Biomarkers in Female Rats

Administration of apple juice, black currant juice, or a 1:1 combination of the two juices significantly decreased the level of the lipid peroxidation biomarker malondialdehyde in plasma of female rats, whereas the protein oxidation biomarker 2-amino-adipic semialdehyde, was significantly increased following administration of orange juice, black currant juice, or the 1:1 combination of apple and black currant juice. A significant increase in 2-amino-adipic semialdehyde was also observed in control rats given sucrose, fructose, and glucose in the drinking water at concentrations approximating the average carbohydrate levels in the employed fruit juices. None of the fruit juices were found to affect the activities of antioxidant enzymes in red blood cells or hepatic glutathione S-transferase. Hepatic quinone reductase activity, on the other hand, was significantly increased by grapefruit juice, apple juice, and black currant juice. The total daily intake of a selected subset of flavonoid aglycones ranged from 0.2 to 4.3 mg, and quercetin was found to be a minor constituent of all the juices investigated. In a parallel study, rats were fed quercetin at doses ranging from 0.001 to 10 g/kg of diet. However, no effects were observed on hepatic glutathione S-transferase or quinone reductase activities, plasma redox status, or the activity of red blood cell antioxidant enzymes. Overall, the results of the present study suggest that commonly consumed fruit juices can alter lipid and protein oxidation biomarkers in the blood as well as hepatic quinone reductase activity, and that quercetin may not be the major active principle. The observation that natural carbohydrates are capable of mediating oxidative stress in vivo warrants further studies due to the central role refined and unrefined carbohydrates play in human nutrition.

Effects of vitamin E supplementation on blood antioxidants levels in patients with Behçet’s disease

Behçet’s disease (BD) is known for many years, yet its etiology remains unknown. In BD, the increased production of reactive oxygen species from activated neutrophils may reduce concentrations of antioxidant vitamins and enzymes in plasma and red blood cells (RBC). Vitamin E is an important fat soluble antioxidant and its role on antioxidant parameters of BD is unclear. The study was undertaken to evaluate the role of vitamin E on lipid peroxidation (MDA) levels, antioxidant vitamin and enzyme concentrations in plasma and RBC in patients with BD. There were three groups i.e., control, patient and treatment groups with twenty-five subjects in each. Nonsmoking patients with BD, patient group, was compared with an equal number of healthy control subjects (control group). Blood samples were taken from both control and patient groups and then oral vitamin E was daily supplemented to the patients with BD for six weeks (treated group). At the end of six weeks, blood was taken from the treated group once more. RBC and plasma MDA levels, serum neopterin, complement system (C 3 and C 4), ASO, CRP, rheumatoid factor, plasma lipoprotein (a), total cholesterol concentrations and erythrocyte sedimentation rate were higher in the patient group than in the control group, but they were lower in the treatment group than in the patient group. While vitamins A, E and β-carotene concentrations in plasma, catalase, glutathione peroxidase activities and reduced glutathione levels in RBC and plasma were lower in patient group than in the controls, they were found to be higher in the treatment group than in the patient group. These results provide some evidence for a potential role of increased lipid peroxidation and decreased enzymatic and non enzymatic antioxidants in BD by its inflammatory character and vitamin E which may strengthen the antioxidant defense system, and may contribute to the treatment of BD.

Identification of G6PD Mediterranean mutation by amplification refractory mutation system

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X chromosome-linked hereditary enzymopathy in humans. The authors have developed an amplification refractory mutation system (ARMS) to detect the G6PD Mediterranean mutation (nt. 563 C→T) that is the most frequent among Caucasian population. Methods: Specific forward polymerase chain reaction (PCR) primers, within exon 6 of the G6PD gene, were designed: ARMS M complementary to the mutated DNA sequence and ARMS N complementary to the wild-type DNA. They were paired with a common reverse primer. The new method was validated using known DNA samples from 72 G6PD-deficient patients carrying the G6PD Mediterranean mutation ascertained by the restriction enzyme analysis. The ARMS test was performed on DNA extracted both from blood or saliva samples. Results: The ARMS test showed an excellent reproducibility and a complete concordance with the endonuclease cleavage reference method. At the same time, it is more rapid and less expensive. Conclusions: The described molecular test may be a method of choice to identify the G6PD Mediterranean mutation. It could also be helpful to obtain a definite diagnosis of G6PD Mediterranean heterozygotes, which is not feasible by using red blood cell enzyme activity measurements.

Effects of α-tocopherol supplementation and continuous subcutaneous insulin infusion on oxidative stress in Korean patients with type 2 diabetes

Most Koreans with type 2 diabetes are insulin deficient and insulin resistant. Continuous subcutaneous insulin infusion (CSII) provides a suitable amount of insulin to overcome insulin deficiency and achieve near-normal blood glucose concentrations. Our previous study showed, however, that CSII does not reduce oxidative stress even though it normalizes blood glucose concentrations. The purpose of this study was to determine whether CSII plus alpha-tocopherol supplementation for 2 mo would alter oxidative stress in Korean patients with type 2 diabetes. Ninety-eight subjects received CSII plus either 200 mg alpha-tocopherol/d (n = 48) or a placebo (n = 50) for 2 mo. The general characteristics (age, duration of diabetes, body mass index, and blood glucose concentrations) of the 2 groups were not significantly different. Fasting and postprandial blood glucose concentrations of all subjects were normalized after CSII. Fasting plasma insulin concentrations did not differ significantly between the 2 groups after CSII. Lipid peroxide concentrations in plasma and red blood cells decreased and alpha-tocopherol concentrations in plasma and red blood cells increased after alpha-tocopherol supplementation. However, these changes were not affected significantly by CSII. Plasma vitamin C concentrations increased significantly after CSII plus alpha-tocopherol supplementation. However, the activities of antioxidant enzymes in red blood cells did not change significantly after CSII plus alpha-tocopherol supplementation. alpha-Tocopherol supplementation was beneficial in decreasing blood lipid peroxide concentrations without altering antioxidant enzyme activities in Korean patients with type 2 diabetes treated with CSII.

Red cell membrane Na+ transport systems in hereditary spherocytosis: relevance to understanding the increased Na+ permeability

Red blood cells (RBCs) in hereditary spherocytosis (HS) show high sodium (Na+) and potassium (K+) movement across the membrane, resulting in dehydration. In general, these abnormal cation fluxes have been interpreted as "increased leaks" due to passive or electrodiffusional permeability of the RBC membrane. A study to elucidate the contribution of concomitant ouabain-resistant pathways (Na-K-2Cl cotransport and Na-Li countertransport) to abnormal Na+ permeability present in RBCs of subjects with HS has been undertaken. Accordingly, erythrocyte Na+ and K+ content and transmembrane cation movements via the Na-K pump, Na-K-2Cl cotransport, Na-Li countertransport, and Na+ passive diffusion, were measured in 25 non-splenectomized patients with HS and compared with the results obtained from the study of 11 patients with congenital non-spherocytic haemolytic anaemia (CNSHA) due to hereditary elliptocytosis (7 cases) and RBC enzyme defects (4 cases) and of 30 normal controls. Compared to the controls, patients with HS exhibited a highly significant (P<0.001) increase in all the Na+ transmembrane movements via passive diffusion (411+/-243 vs 105+/-40), Na-K pump (2615+/-970 vs 1874+/-359), Na-K-2Cl cotransport (males: 371+/-138 vs 190+/-42; females: 401+/-134 vs 104+/-44) and Na-Li countertransport (207+/-131 vs 98+/-41). This was associated with increased Na+ and decreased K+ content, resulting in a reduction of total cation (Na+ + K+) RBC concentration. Furthermore, significant correlations were also found between the patients' RBC cationic content and the mean corpuscular haemoglobin concentration (MCHC) (r=0.51, P<0.05) and between the Na+ passive leak and the haematocrit value (r=-0.44, P<0.05). In the patients with CNSHA, a less significant (P<0.01) increase of active (Na-K pump) and passive (leak) transmembrane permeability to Na+ was associated with normal transmembrane movements via Na-K-2Cl cotransport and Na-Li countertransport. The present study demonstrates that in HS, RBCs are characterized by a variable, but always significant increase of all the membrane transport systems leading to the extrusion of Na+, and that these abnormalities, regardless of their relation to membrane structural defects, may probably be valuable for the differential diagnosis between HS and other congenital defects of RBCs.

Effects of melatonin on enzyme activities of glucose-6-phosphate dehydrogenase from human erythrocytes in vitro and from rat erythrocytes in vivo

The in vivo and in vitro effects of melatonin on glucose-6-phosphate dehydrogenase (G6PD) from human erythrocytes have been investigated. For this purpose, human erythrocyte glucose-6-phosphate dehydrogenase was purified, at the beginning, 13.654 times in a yield of 28% by using ammonium sulphate precipitation and 2′ ,5 ′ - ADP Sepharose 4B affinity gel. A temperature of +4∘C was maintained during the purification process. Enzyme activity was determined by the Beutler method using a spectrophotometer at 340 nm. This method was utilized for all kinetic studies. For in vitro experiments, the enzyme activity increased below 0.08 mM melatonin concentration and reached a plateau above 0.1 mM. Ten mg kg−1melatonin was administered intraperitonally and indicated the stimulatory effect on the enzyme. Time-dependent in vivo studies were executed for melatonin in Sprague–Dawley type rats. It was found that G6PD activity in the erythrocytes was increased by the melatonin in 1.5 and 3.5 h. These results show that both in vitro(below 0.08 mM) and in vivo pharmacological levels of melatonin increased enzyme activity in erythrocytes. The findings also indicate that melatonin may be pharmacologically useful in patients where a deficiency of the enzyme in red blood cells (RBC) causes haemolytic anaemia.

Value of Aspergillus niger fermentation product as a dietary ingredient for broiler chickens

The experiment reported was a study on Aspergillus niger inoculation into the waste liquor from glutamate manufacturing and used as a dietary protein source for broilers. The program involved a toxicological and nutritional evaluation of the product using a short-term toxicity and a nutritional feeding trial in broilers. Both trials involved a total of 800 broilers from the commercial Arbor Acres strain. Equal numbers of males and females were randomly allocated into 20 pens with five dietary treatments and four replicates for the 6-week feeding trials. The dietary treatment involved graded levels of SCP inclusion, 0, 47, 95, 142, 189 g/kg and 0, 35.5, 71, 106.5, 142 g/kg, in starter and finisher maize–soya bean meal basal rations, respectively. Blood and specimens from various visceral organs were taken at the end of the toxicological trial for analysis of blood constituents and for clinical and pathological examination. Data on the performance and nutrient utilization efficiency were recorded during the feeding trial. Carcass analysis and a taste panel were also conducted to evaluate consumer acceptance at the end of the trial. Results showed that the intestinal weights of certain intestinal segments increased ( P<0.05), and the red blood cell (RBC), hemoglobin (Hb), hematocrit and blood enzyme activity, aspartate amino transferase (AST) and alanine amino transferase (ALT), significantly decreased as the dietary level of SCP increased ( P<0.05). Pathological results did not show any abnormality due to the SCP inclusion. Increasing amounts of SCP inclusion in the broiler diet linearly depressed weight gain and feed conversion in the 0–6 week broilers ( P<0.05). Each 10 g increment of SCP in kilogram diet decreased the live-weight gain of the broilers by 6.3 g and required an increase of 0.14 g feed to convert to 100 g of gain. Increased levels of SCP inclusion, however, showed a trend toward depressed feed intake during the finishing period ( P=0.053) and the entire feeding period ( P=0.053). Inclusion of SCP did not significantly influence the color, aroma and tenderness of breast meat, but significantly influenced breast meat flavor ( P<0.05). The flavor of the breast meat linearly increased as the concentration of dietary SCP increased ( Y=2.88+0.0137 X) ( S yx =0.88; P<0.05).

Evaluation of superoxide dismutase and glutathione peroxidase enzymes and their cofactors in Egyptian children with Down's syndrome.

The present work investigated the activity of Cu/Zn superoxide dismutase enzyme (SOD) in red blood cells and glutathione peroxidase enzyme (GPx) in whole blood by spectrophotometric methods. Plasma levels of the cofactors copper and zinc and whole-blood selenium were evaluated using atomic absorption spectrophotometer. The study included a population of 18 Down's syndrome (DS) patients with complete trisomy 21 (group 1), translocations (group 2), and mosaicism (group 3), and their 15 matched controls. The purpose of this work was to study the gene dosage effect of SOD and its consequence on GPx enzyme and the various cofactors, and to find out correlations with developmental fields. Our results showed that in the population with complete trisomy 21 and translocations, SOD and GPx activities were increased, whereas in cases with mosaicism, the enzymes activities were within normal limits. Plasma copper concentrations were increased, whereas whole-blood selenium concentrations were significantly decreased in the three DS groups. Plasma zinc levels were within normal in all patients. We concluded that changes in trace elements and enzyme activities were not related to age or sex. Also, there was no correlation between the enzyme levels and the developmental activities. Our results are useful tools for identifying nutritional status and guiding antioxidant intervention.

Apportionment of racial diversity: A review

It has become increasingly popular to theorize and assert significant genetic differences between arbitrary regional, ethnic, and racial groupings of humans. Beginning with Livingstone, Brace, and Newman is the early 1960s, biological anthropologists have shown that variation in human traits is non-concordant along racial lines, as they are products of overlapping, dynamic selective pressures. In 1972, Lewontin analyzed blood groups, serum protein, and red blood cell enzyme variants and found that only about 6% of total genetic variance was accounted for by race, while the majority of variance is accounted for by differences between individuals. Using similar assays, Latter obtained similar results in 1980. In 1982, Nei and Roychoudhury analyzed 62 protein variants and 23 blood groups, finding that roughly 10% of genetic variance was accounted for by race. Analyzing protein, blood group, and HLA variants, Ryman and coworkers obtained similar figures in 1983. More recently, Dean and coworkers (1994) and Barbujani and coworkers (1997) have used PCR techniques to analyze RFLP and microsattelite loci, again yielding estimates of around 10% for the amount of genetic variance accounted for by race. Furthermore, recent research on regional and racial variance in mtDNA (Excoffier and coworkers, 1992), a traditional marker for human racial groupings, shows a higher proportion of variance within than across racial categories. These studies used a variety of assays and analytical techniques, some of which are designed to maximize the amount of variance accounted for by race. In light of this, the low proportion of genetic variance across racial groupings strongly suggests a re-examination of the race concept. It no longer makes sense to adhere to arbitrary racial categories, or to expect that the next genetic study will provide the key to racial classification.