A Mediterranean diet supplemented with extra virgin olive oil or nuts improves endothelial markers involved in blood pressure control in hypertensive women

PURPOSE

Serum nitric oxide (NO) reduction and increased endothelin-1 (ET-1) play a pivotal role in endothelial dysfunction and hypertension. Considering that traditional Mediterranean diet (TMD) reduces blood pressure (BP), the aim of this study was to analyze whether TMD induced changes on endothelial physiology elements such as NO, ET-1 and ET-1 receptors which are involved in BP control.

METHODS

Non-smoking women with moderate hypertension were submitted for 1 year to interventions promoting adherence to the TMD, one supplemented with extra virgin olive oil (EVOO) and the other with nuts versus a control low-fat diet (30 participants/group). BP, NO, ET-1 and related gene expression as well as oxidative stress biomarkers were measured.

RESULTS

Serum NO and systolic BP (SBP) or diastolic BP (DBP) were negatively associated at baseline, as well as between NO and ET-1. Our findings also showed a DBP reduction with both interventions. A negative correlation was observed between changes in NO metabolites concentration and SBP or DBP after the intervention with TMD + EVOO (p = 0.033 and p = 0.044, respectively). SBP reduction was related to an impairment of serum ET-1 concentrations after the intervention with TMD + nuts (p = 0.008). We also observed changes in eNOS, caveolin 2 and ET-1 receptors gene expression which are related to NO metabolites levels and BP.

CONCLUSIONS

The changes in NO and ET-1 as well as ET-1 receptors gene expression explain, at least partially, the effect of EVOO or nuts on lowering BP among hypertensive women.

Role of oxidative stress and adenosine nucleotides in the liver of aging rats

We studied the response of several parameters related to oxidative stress in the liver of aging rats. Male Wistar rats aged 1.5, 3, 18 and 24 months were used. Livers showed an increase in superoxide anion (O(2)(-)) concentration at 1.5 and 18 months of age compared to the 3-month-old group; a decrease in superoxide dismutase (SOD) was seen at 1.5 months and catalase concentrations remained unaltered throughout the aging process. Nitric oxide (NO) progressively declined with age; a significant decrease was particularly apparent at 18 and 24 months of age. Thiobarbituric acid reactive substances (TBARS) decreased significantly at 1.5 months, whereas it increased at 18 and 24 months of age. Concentrations of prostaglandin E(2) (PGE(2)), and adenine nucleotides, and their metabolites, remained unchanged throughout the aging process. Although the mitochondrial damage caused by oxidative stress can result in reduced ATP production and compromised cell function, our results on adenosine nucleotides and their metabolites support the notion that the integrity of mitochondria and enzymatic activity remain mostly unchanged with aging. In conclusion, we observed a significant decrease in the levels of NO in the older groups of rats and hence in its antioxidant activity. This could explain the observed increase in lipid peroxides which suggests an important role for NO in oxidative stress in the liver of older rats.

Toxicity and antioxidant activity in vitro and in vivo of two Fucus vesiculosus extracts

The consumption of seaweeds has increased in recent years. However, their adverse and beneficial effects have scarcely been studied. Two extracts from the brown seaweed Fucus vesiculosus containing 28.8% polyphenols or 18% polyphenols plus 0.0012% fucoxanthin have been obtained and studied to determine their toxicity in mice and rats and also their antioxidant activity. Both extracts were shown to lack any relevant toxic effects in an acute toxicity test following a 4 week daily treatment in rats. The extracts exhibited antioxidant activity in noncellular systems and in activated RAW 264.7 macrophages, as well as in ex vivo assays in plasma and erythrocytes, after the 4 week treatment in rats. Our ex vivo results indicated that compounds from extract 2 may be more easily absorbed and that the antioxidants in their parent or metabolized form are more active. These findings support the view that the daily consumption of F. vesiculosus extract 2 (Healsea) would have potential benefits to humans.

Dealcoholized red and white wines decrease oxidative stress associated with inflammation in rats

In vitroexperiments have demonstrated that polyphenols exhibit antioxidant and anti-inflammatory activities. The present study was designed to test whether dealcoholized red (DRW) and white (DWW) wines can decrease the oxidative stress associated with inflammationin vivo. Rats were fed for 15 d either a control diet or one supplemented with DRW or DWW. Finally, a granuloma was induced by subcutaneous administration of carrageenan. Although DRW showed higher antioxidant activityin vitrothan DWW, both wines decreased the number of cells recruited into the granuloma pouch. Malondialdehyde decreased in plasma and inflammatory exudate from rats fed with DRW- and DWW-rich diets. Moreover, the concentration of NO increased in exudate, which correlates with the increase in the citrulline:arginine ratio. Polymorphonuclear leucocytes from the inflammatory exudate of rats fed dealcoholized wines showed decreased superoxide anion (O2∙−) production and increased NO productionex vivo. This change in NO production resulted from increased expression and activity of inducible NO synthase (EC 1.14.13.39). Moreover, the up regulation of cyclo-oxygenase-2 (EC 1.14.99.1) protein expression observed in rats fed the DRW-rich diet was not related to a direct effect of NO. The present results indicate that the non-alcoholic compounds of wines not only improve antioxidant status in an inflammatory situation, but also limit cell infiltration, possibly through a decrease in O2∙−and an increase in NO production.

Effects of fish oil- and olive oil-rich diets on iron metabolism and oxidative stress in the rat

The objective of the present study was to examine the effects of fish oil (FO)- and olive oil (OO)-rich diets on Fe metabolism and oxidative stress. Rats were fed for 16 weeks with diets containing 50 g lipids/kg; either OO, maize oil (MO) or FO. OO or MO diets contained a standard amount (100 mg/kg) of all-rac-alpha-tocopheryl acetate. FO diets were supplemented with 0, 100 or 200 mg all-rac-alpha-tocopheryl acetate/kg (FO-0, FO-1 or FO-2 diets, respectively). At the end of the feeding period, we measured non-haem Fe stores in liver and spleen, and erythrocyte and reticulocyte count. We also determined antioxidants and products derived from lipid peroxidation in plasma and erythrocytes. Our results showed reduced non-haem Fe stores in rats fed any of the FO diets. Reticulocyte percentage was higher in the rats fed FO-0 and FO-1. Plasma alpha-tocopherol was very low in rats fed the FO-0 diet. Rats fed the FO-1 and FO-2 diets showed higher alpha-tocopherol in plasma than the FO-0 group but lower than the MO or OO groups. We did not observe such differences in the alpha-tocopherol content in erythrocyte membranes. Superoxide dismutase and glutathione peroxidase activities were lower in the erythrocytes of rats fed the FO-0 diet. The products derived from lipid peroxidation were also higher in the FO groups. The administration of FO-rich diets increased lipid peroxidation and affected Fe metabolism. On the other hand, the OO-rich diet did not increase oxidative stress and did not alter Fe metabolism. Based on these results, we conclude that FO supplementation should be advised carefully.

Extracellular pH affects inflammatory cell production of superoxide and nitric oxide

Previous research has described how high cellular metabolism creates an acidic environment in inflammatory cells during respiratory burst. The aim of our work was to describe the acid-base dependence of exudate in superoxide (O2.-) and nitric oxide (NO.) generation by inflammatory cells from a carrageenan-granuloma. Although the carrageenan solution was alkaline (pH 7.74 when equilibrated with air) the exudate showed an acidification that stabilised at around 7 units of pH. A notable hypercapnia, but not hypoxia, was found in the exudate at up to 24 h. The effect of extracellular acidosis on O2.- and NO. production by inflammatory cells was also studied. The maximum O2.- production and the lowest levels of NO. were found at pH 7, which was closer to the pH of the granuloma-pouch. These results suggest that experiments with inflammatory cells ex vivo should be carried out at an identical pH to that found in vivo in order to reproduce the physiological mechanisms of free radical generation during inflammatory processes.

A flavonoid-rich diet increases nitric oxide production in rat aorta

1. Red wine intake is associated with a low risk of cardiovascular disease. This effect has been partly attributed to the action of polyphenolic compounds, which decrease the oxidation of plasma low density lipoproteins. Moreover, nitric oxide ((*)NO) is a vasodilator and polyphenolic compounds induce endothelium-dependent vasorelaxation in vitro. 2. Here we studied whether a diet rich in dealcoholated red wine (DRW) increases acetylcholine-induced vasorelaxation and whether ingestion of DRW-, quercetin- or catechin-rich diets modifies the (*)NO-cyclic guanosine-3',5'-monophosphate (cyclic GMP) pathway and superoxide anion (O2(.-)) release in aorta in a resting state in rats fed semi-purified diets containing either 35% (v w(-1)) DRW, 0.3% (w w(-1)) quercetin or 0.3% (w w(-1)) catechin for 10 days. 3. (*)NO-mediated vasorelaxation induced by acetylcholine was greater in rats fed the DRW-rich diet than in those that received the control diet. 4. Expression of endothelial (*)NO synthase (eNOS) was similar in the four dietary groups. The aortic rings of rats fed either the DRW-, quercetin-, or catechin-rich diets showed higher NOS activity, (*)NO production and cyclic GMP content than those of rats fed the control diet. No changes were observed in O2(.-) production. 5. In summary, diets rich in either DRW, quercetin or catechin induced endothelium-dependent vasorelaxation in rat aorta in a resting state through the enhancement of (*)NO production, without modifying O2(.-) generation, thus the bioavailability of (*)NO was increased. The increase in the (*)NO-cyclic GMP pathway explains the beneficial effect of flavonoids at vascular level.

Olive oil decreases both oxidative stress and the production of arachidonic acid metabolites by the prostaglandin G/H synthase pathway in rat macrophages

Fish oil has a preventive role in cardiovascular and inflammatory diseases, but little is known about the effect of olive oil, which is widely consumed in Mediterranean regions. We examined the influence of dietary olive oil, corn oil and fish oil-rich diets on the production of superoxide anion (O2-) and nitric oxide (.NO) by resident macrophages stimulated by phorbol 12-myristate 13-acetate (PMA) and their effect on arachidonic acid release, prostaglandin G/H synthase-2 (PGHS-2) expression and the subsequent prostaglandin E(2) production. Resident peritoneal macrophages stimulated by PMA from rats fed with olive oil or corn oil had the same level of O2- production, but these levels were increased by the fish oil diet. Olive oil and the fish oil diets increased .NO and decreased arachidonic acid mobilization and the production of prostaglandin E(2). PGHS-2 expression, however, was not affected by diet. We conclude that although olive oil and fish oil reduce arachidonic acid mobilization and subsequent metabolism through the PGHS-2 pathway in PMA-stimulated macrophages, only olive oil offers an additional beneficial effect by increasing .NO/O2- production.

Free radical production in aortic rings from rats fed a fish oil-rich diet

To study the effect of the degree of unsaturation of dietary fatty acids on the production of free radicals and on the vascular smooth muscle tone in rings of the aorta, Sprague-Dawley rats were fed a semipurified diet containing 5% lipids from either corn oil (CO) or menhaden oil (MO) for 8 wk. The MO diet did not change the basal or NADPH-dependent superoxide anion (O[Formula: see text]·) release. There were no significant differences in phenylephrine-induced contractions between the two groups in intact rings. However, these contractions increased in endothelium-intact aortic rings from the MO group after addition of the nitric oxide (·NO) synthase inhibitor N G-nitro-l-arginine and in endothelium-denuded rings, both indicating a greater endothelial basal ·NO production in rats fed with the MO diet. Endothelium-dependent relaxations in response to acetylcholine were more prominent in rings from the MO group. These differences were not due to an increased smooth muscle response to ·NO, because relaxations were the same using an exogenous ·NO donor. Our results indicate that dietary MO did not modify O[Formula: see text]· release by the vessel wall or relaxation due to the cyclooxygenase pathway, but it potentiated endothelial production of ·NO.

Different roles for nitrogen monoxide and peroxynitrite in lipid peroxidation induced by activated neutrophils

We studied the roles of nitrogen monoxide (NO&z.rad;) and peroxynitrite produced by the polymorphonuclear leukocytes (PMNs) isolated from an inflammatory exudate. PMNs were incubated either in a medium with a submicromolar concentration of iron or in a diethylenetriaminepenta-acetic acid (DTPA)-containing medium, and stimulated with phorbol 12-myristate 13-acetate (PMA) to generate free radicals. In both conditions superoxide anion (O(2)(*)(-)), NO&z.rad; and peroxynitrite were produced. In the presence of arachidonic acid, malondialdehyde (MDA) was generated. This MDA was generated in one of two way; the peroxynitrite iron-independent mechanism (40%) and the Fenton reaction, caused by free iron (60%). We also observed that the addition of L-arginine was followed by a 42% reduction in MDA, which can be explained by the antioxidant effect of NO&z.rad;. These results indicate that lipid peroxidation can occur in the absence of iron, through a peroxynitrite-mediated mechanism, and that NO&z.rad; may act as an antioxidant when it is produced in large amounts.

Local and systemic responses to iron-dextran injected into a granuloma pouch in the rat

Many inflammatory processes are accompanied by anemia and repeated hemorrhages, but the local and systemic effect of the iron present in the inflamed area and the availability of this iron are not known. The experimental model used to mimic the above situation was the carrageenan-induced granuloma in rats with simultaneous iron-dextran injection into the granuloma pouch. We studied the effect of iron-dextran on leukocytes from the inflammatory exudate and the location of iron in the granuloma tissue. We also evaluated the systemic responses by studying several iron parameters in blood and in iron-storage organs. The results showed a reduction in the number of leukocytes present in the exudate and a reduction in their viability and also extensive damage to the granuloma tissue, essentially to macrophages, caused by local iron-induced oxidative stress. A small percentage of iron reaches the systemic circulation, and this is eventually stored in the liver and spleen as hemosiderin, which is unlikely to have any effect on anemia. In spite of its local toxicity, the accumulation of iron in inflamed areas can be interpreted as a protective mechanism against systemic oxidative radical reactions induced by iron mobilization.

Nitric oxide inhibits superoxide production by inflammatory polymorphonuclear leukocytes

Nitric oxide (NO.) has a complex role in the inflammatory response. In this study, we modified the levels of endogenous NO. in vivo in an acute model of inflammation and evaluated the interactions between NO. and superoxide anion (O2-.) produced by polymorphonuclear leukocytes (PMNs) accumulated in the inflamed area. We injected phosphate-buffered saline (control group), 6 mumol of L-N5-(1-iminoethyl)ornithine (L-NIO group), or 6 mumol of L-arginine (L-arginine group) into the granuloma pouch induced by carrageenan in rats. NO2- plus NO3- (indicative of NO. generation) was 188 nmol in the exudate of the control group, but it decreased in the L-NIO group (P < 0.05) and increased in the L-arginine group (P < 0.05). When PMNs from treated rats were incubated in vitro, the production of superoxide anion (O2-.) decreased by approximately 46% in the L-arginine group. Furthermore, O2-. was inhibited in PMNs when L-arginine was added to the incubation medium before phorbol 12-myristate 13-acetate stimulation but not when added simultaneously. Our results suggest a protective role for NO. in inflammation, through the inactivation of NADPH oxidase and the consequent impairment of O2-. production for cell-mediated injury.

The Mpl-ligand is involved in the growth-promoting activity of the murine stromal cell line MS-5 on ES cell-derived hematopoiesis

We investigated the ability of the murine stromal cell line MS-5 to enhance the hematopoietic potential of embryonic stem (ES) cells. The presence of increasing concentrations of MS-5 cells during the differentiation of ES cells into embryoid bodies (EBs) resulted in a positive dose effect on the efficiency of EB development. Moreover, the number of myeloid progenitors derived from EBs at days 6 and 10 of differentiation significantly increased. This increase resulted from an elevation of both the proportions of positive EBs (EBs containing at least one progenitor each) and the progenitor cell content per positive EB. The stimulatory activity of MS-5 cells affected all types of myeloid progenitors except erythroid progenitors, which were depressed. However, the relative numbers of ES-derived granulocyte-macrophage progenitors (colony-forming units granulocyte/macrophage [CFU-GM], -macrophage [CFU-M], and -granulocyte [CFU-G]) and of mixed cell colonies were unchanged. In contrast, the incidence of megakaryocytic progenitors (colony-forming units-megakaryocyte [CFU-MK]) was significantly increased, that of erythroid progenitors (burst-forming units-erythroid [BFU-E]) was concomitantly decreased, and the total numbers of both progenitor types remained constant. Addition of Mpl-ligand (Mpl-L; thrombopoietin) during the growth of EBs was found to mimic the effect of the MS-5 cell line on the output of progenitor cells. No effect of Mpl-L on the efficiency of EB formation was observed. In addition, supplementation of cultures with sufficient soluble Mpl to abrogate Mpl-L activity resulted in the reversion of the quantitative and qualitative effects of MS-5 cells on progenitor cell formation but not on the efficiency of EB formation. Together, these data indicate two major effects and two levels of action of the MS-5 cell line on hematopoietic differentiation of ES cells. First, the cell line acts before hematopoietic determination, promoting the plating efficiency of ES cells via mechanisms that remain to be clarified. Second, at a later stage of differentiation, the MS-5 cells promote hematopoiesis within EBs. Mpl-L appears to be one of the components that confer this latter ability on the MS-5 cell line.

Fish oil and oxidative stress by inflammatory leukocytes

We investigated the effects of diets with different fatty acid composition upon the oxidative stress of inflammatory leukocytes of rats. After weaning, two groups of rats were fed isoenergetic semipurified diets for five weeks containing 5% of corn oil or menhaden oil. Polymorphonuclear leukocytes from rats fed menhaden oil diet incorporated n-3 polyunsaturated fatty acids into phospholipid membranes at the expense of arachidonic acid. These cells showed diminished superoxide production and, as a consequence, the total antioxidant status in the inflammatory exudate was increased. However, nitric oxide production was not affected by diet. Free malondialdeyde concentration increased in the exudate because of lower mitochondrial activity. These results add new aspects that help clarifying the anti-inflammatory mechanisms of n-3 polyunsaturated fatty acids.

Fatty acid composition of erythrocyte membranes affects iron absorption in rats

We studied the influence of the fatty acid composition of three different diets on iron absorption in relation to the lipid peroxidation of the erythrocyte membranes. After weaning, three groups of rats were fed isoenergetic semipurified diets for 16 wk: control diet (containing canola oil and peanut oil), tripalmitin diet (a saturated fatty acid diet) and a sardine oil diet rich in polyunsaturated fatty acids. Eight rats from each group were administered 59FeSO4 by gastric intubation for ferrokinetic studies, and six rats from each group were used for several analyses in blood, liver, spleen and erythrocytes. Results obtained from 59Fe eliminated in feces and 59Fe present in plasma, both calculated by the area under the curve and from maximum concentration in plasma, indicated that the sardine oil diet induced higher iron absorption than the control diet. The lipid peroxidation of erythrocyte membranes in rats fed sardine oil was higher than that in control rats due to high membrane's (n-3) polyunsaturated fatty acid content and low alpha-tocopherol level. The 59Fe in liver and spleen of rats fed the sardine oil diet was higher than in rats fed the control diet, and 59Fe was diverted to erythrocytes to a greater extent than in rats fed the control diet due to their reduced life-span. The sardine oil diet, by lessening alpha-tocopherol and raising the degree of lipid peroxidation in erythrocytes, augments iron absorption, whereas the tripalmitin diet, by protecting erythrocyte membranes from lipid peroxidation, leads to a lower rate of iron absorption.

Factors influencing the acid-base changes in the air-pouch exudate following carrageenan induced inflammation in rats

The interactions between the acid-base variables that contribute to exudate acidosis were studied in the subcutaneous air-pouch after carrageenan injection in rats. We studied the concurrent changes of exudate gases (PCO2 and PO2), main ions ([Na+], [K+], [Ca2+], [Mg2+], [Cl-] and [Lac-]), inorganic phosphate (P(i)) and albumin in acutely inflamed rats (4, 8, 12, 24 and 48 h of inflammation). A notable hypercapnia was found in the exudate after only 8 h (exudate PCO2 = 64.3 +/- 2.9 mm Hg) but this hypercapnia decreased after 48 h (32.9 +/- 12.7 mm Hg), coincident with the greatest increase in exudate cells. With respect to the metabolic acid-base variables, the most important changes found were a parallel decrease in the strong ion difference ([SID]) and exudate pH, as well as increases in the exudate weak acid buffers ([ATOT]) due to albumin and inorganic phosphate (P(i)) increases. However, after 12 h, the exudate acidosis was stable at around pH 7. A similar acid pH was obtained after 24 h of inflammation when the carrageenan solution injected was previously adjusted to a physiological pH (7.4). This pH, analogous to that of the exudate, was the result of compensation by the acid-base independent variables, a fact which suggests that acid pH may be a beneficial condition for cells taking part in inflammatory processes.

Effect of degree of unsaturation in dietary fatty acids on arachidonic acid mobilization by peritoneal macrophages

Cells from rats fed with a tripalmitin diet showed a depletion of phospholipid arachidonate and n-3 fatty acids such as eicosapentaenoic and docosahexaenoic acids (EPA and DHA). In rats fed fish oil diet, a significant reduction in arachidonic acid (AA) content was observed whereas EPA and DHA were incorporated into membranes lipids. These changes in lipid composition of membranes did not affect cellular adherence, phagocytic capability, or [3H]AA incorporation. However, both tripalmitin and fish oil diets induced a decrease in [3H]AA mobilization stimulated by 4 beta-phorbol-12-myristate 13-acetate, A23187, or opsonized-zymosan in rat peritoneal macrophages. These results demonstrate that the antiinflammatory effects of essential fatty acids deficiency or n-3 enrichment diets may be associated with a decreased AA mobilization in resident rat peritoneal macrophages treated with proinflammatory agents.

Conditions to study nitric oxide generation by polymorphonuclear cells from an inflammatory exudate in rats

Superoxide and nitric oxide release by leukocytes has been usually performed after exposure to a particular stimulus. We measured the generation of superoxide and nitric oxide by cells isolated from an inflammatory exudate of rats in either the absence or the presence of a variety of stimuli. Nonstimulated leukocytes generated superoxide radical (1.2 nmol x 10(6) cells(-1)) and nitric oxide (3.8 nmol x 10(6) cells(-1)) after 2 h incubation. When cells were incubated with lipopolysaccharides, opsonized zymosan or phorbol 12-myristate 13-acetate, superoxide level increased while nitric oxide decreased. Phorbol 12-myristate 13-acetate (100 ng/ml) induced a decrease of 0.88 nmol x 10(6) cells(-1) compared with nonstimulated cells, and incubation with N-iminoethyl-L-ornithine increased superoxide production by 0.81 nmol x 10(6) cells(-1). These results provide clear evidence that cells from an inflammatory exudate which are already triggered are able to generate a considerable amount of nitric oxide and in less proportion superoxide, that the measure of nitric oxide must be performed without a further stimulus, and that both molecules react in an equimolar proportions to give peroxynitrite anion.

Blood acid-base changes during acute experimental inflammation in rats

Acidosis has often been reported in inflamed tissues, and changes in strong relevant ions at the site of inflammation may provoke alterations in blood acid-base status. We measured changes in blood acid-base variables during carrageenan-induced inflammation in rats. We found a mixed acid-base disorder in rat blood during acute inflammation (12, 24, and 48 h). A metabolic acid contribution was found during the first 12 h and maintained further, as revealed by a decrease in plasma strong ion concentration difference ([SID]) and an increase in plasma weak acid concentration due to a rise in inorganic phosphate ([ATOT]P(i)). Plasma [SID] and [ATOT]P(i) changes were probably due to exchange of Na+ and P(i) between the inflammatory exudate and rat blood. A secondary respiratory compensation for the metabolic acid changes occurred in the blood of inflamed rats, resulting in significant hypocapnia. Furthermore, a progressive decrease in the total weak acid buffer concentration due to a decrease in plasma albumin ([ATOT]Alb) also counteracted the impact of changes in [SID] and P(i) to increase blood acidity. Therefore, despite the metabolic acid-base disorders induced by inflammatory processes, hydrogen ion (H+) homeostasis was maintained, and blood pH remained essentially unchanged in the inflamed rats.

Missense mutation of the erythropoietin receptor is a rare event in human erythroid malignancies

Human erythroid malignancies (polycythemia vera [PV] and erythroleukemia) are associated with erythropoietin (Epo)-independent growth and differentiation. Missense or nonsense mutations in the Epo receptor (Epo-R) have been recently described in experimental erythroleukemia in mice and in cases of erythrocytosis in humans. To search for a similar genetic alteration in erythroleukemia and PV, we entirely sequenced the exons of the Epo-R gene as well as the intron-exon junctions in these disorders using polymerase chain reaction. In 1 of 10 cases of erythroleukemia, a single allele mutation was found in the 8th Epo-R gene exon that changed asparagine 487 into a serine. No Epo-r gene mutation was found in 12 PV cases studied, but the same mutation (N487S) was found in 1 patient with polycythemia that did not fulfill the criteria of PV (polycythemia of unknown origin). We did not detect this mutation after sequencing part of the 8th exon of the Epo-R gene from 21 other patients with polycythemia of unknown origin and 51 normal controls. The Epo-R mutation was also found in Epstein-Barr virus-derived cell lines from both cases, suggesting that it is not related to the malignant clone. Therefore, this mutation does not appear to be somatic, although no familial cases were found. The biologic effect of this mutation was subsequently studied. Erythroid progenitors from the polycythemic patient normally responded to Epo, whereas those from the erythroleukemic patient were Epo-independent due to autocrine stimulation by Epo. The normal and the mutated Epo-R were transfected into the murine Ba/F3 cell line. Both types of cells displayed the same response to Epo for proliferation, differentiation, and inhibition of apoptosis. Although this mutation may destroy a consensus binding site for Grb2, no obvious differences either in the pattern of Epo-induced tyrosine phosphorylated proteins or in the binding of Grb2 to the Epo-R were observed. In conclusion, a somatic Epo-R missense mutation does not appear to be a molecular mechanism involved in the abnormal growth of human erythroleukemia and PV. However, the Epo-R mutation (N487S) that we describe is located in the same tyrosine sequence beginning at AA 485 as the one previously observed (P488S) in as case of polycythemia (Sokol et al, Exp Hematol 22:447, 1994). These results suggest that this phosphopeptide sequence may play an important role in Epo signalling.

Iron metabolism and oxidative stress during acute and chronic phases of experimental inflammation: effect of iron-dextran and deferoxamine

Iron overload induces a rise in lipid peroxidation, but there are no data on the effects of iron administered in vivo on the production of free radicals by inflammatory cells. Further, there is lack of agreement about the benefits of deferoxamine (Dfx) in the treatment of anemia and oxidative stress during inflammation and chronic diseases. In this study, iron-dextran (Fe-dextran) or Dfx was administered subcutaneously during the acute and chronic phases of carrageenan-induced granuloma. Several parameters related to iron metabolism, inflammatory cell activity, and lipid peroxidation were measured in liver, plasma, and the inflammatory exudate. Treatment with Fe-dextran increased iron content in plasma and in stores, increased production of superoxide anion (O2-) by inflammatory cells and lipid peroxidation, and also altered the inflammatory process. Dfx mobilized iron from stores without modifying essential parameters related to anemia or to the level of lipid peroxidation induced by inflammation. We conclude that treatment with Fe-dextran had a beneficial effect on recovery from the anemia of inflammation. Nevertheless, the high levels of loosely-bound iron found after Fe-dextran treatment in plasma and in exudate contribute to the increase in oxidative stress. Dfx treatment had no effect on anemia or on lipid peroxidation.

Dietary lipid and iron status modulate lipid peroxidation in rats with induced adjuvant arthritis

We studied the effect of dietary lipids on iron metabolism and lipid peroxidation during induced adjuvant arthritis and/or iron overload in rats. We compared a control diet containing corn oil and rapeseed oil with a diet devoid of polyunsaturated fatty acids containing only tripalmitin as lipids. Four subgroups of rats were used with each diet: without further treatment, with induction of adjuvant arthritis, with iron overload, and with induction of adjuvant arthritis and iron overload. The profile of fatty acids present in plasma and in microsomes changed in rats fed the tripalmitin diet. The level of tetra- and pentaunsaturated fatty acids was reduced, and the level of monounsaturated fatty acids and iron stores was increased with respect to control rats. Thus, ingestion of a tripalmitin diet reduced the substrate for lipid peroxidation, as shown by the decrease in thiobarbituric acid-reactive substances in plasma and conjugated dienes in hepatic microsomal fraction. Adjuvant arthritis and iron overload had a synergistic effect on lipid peroxidation and iron storage in liver. Further, in the hepatic microsomal fraction, tripalmitin reduced the levels of cytochrome P-450, and arthritis reduced the levels of cytochrome P-450 and Ca2+ sequestration. Our results suggest that rats fed tripalmitin showed a reduction of lipid peroxidation induced by inflammation or by iron overload, because of the lack of polyunsaturated fatty acids in the diet, although tripalmitin usually increases the iron stores in the body and causes hepatic alterations.

Simultaneous generation of nitric oxide and superoxide by inflammatory cells in rats

It has recently been shown that peroxynitrite anion is a powerful oxidant than can initiate lipid peroxidation. As this oxidant is the product of the reaction between nitric oxide and superoxide, we have studied whether cells isolated from an inflammatory exudate can release both radicals simultaneously under physiological conditions. The carrageenin-induced granuloma model in rats was used. Cells from the inflammatory pouch were stimulated with opsonized zymosan in the absence or in the presence of exogenous L-arginine. Nitric oxide production without exogenous L-arginine was detectable after 15 min (0.29 nmol NO2-) and increased with time (1.65 nmol NO2- at 4 h). When nitrite released from cells was expressed as a rate a burst was shown in the first few minutes. Between 0 and 15 min, cells produced NO2- at the following rates: 20 pmol NO2-/1 x 10(6) cells/min without exogenous L-arginine and 83 pmol NO2-/1 x 10(6) cells/min with exogenous L-arginine. Production was further stimulated with opsonized zymosan (92 pmol NO2-/1 x 10(6) cells/min), and inhibited by L-NMMA and L-NIO. The production of superoxide increased for up to 2 h and then stabilized. A significant increase in nitrite was observed in the presence of SOD, whereas L-NIO increased superoxide generation. These results suggest that peroxynitrite anion may be formed by inflammatory cells.

Effect of carrageenan-induced granuloma on hepatic cytochrome P-450 isozymes in rats

Carrageenan-induced granuloma was used to study the apoprotein and RNA content, and catalytic activities of several cytochrome P-450 isozymes in liver. This model allowed discrimination between acute and chronic phases of experimental inflammation. The expression of most isozymes studied (CYP2D, CYP2E1, CYP3A1 and CYP4A) was reduced to 20% of the control level during the acute phase and partially recovered (30-60% of control group) during the chronic phase. CYP2B1 content was decreased to 65% of control during the acute and chronic phases of inflammation. RNA (CYP2B1 and CYP2E1) showed a strong depression during the acute phase and recovered during the chronic phase, without differences between isoenzymes. In most cases, there was a good correlation between the apoprotein content of isozymes and related activities. Our results show that the depletion of cytochrome P-450 induced by inflammation depends on the severity of the disease. Experimental inflammation equally affect the transcription of CYP2B1 and CYP2E1, so differences in apoprotein content and related activities between isozymes may due to differential posttranscriptional regulation.

Autocrine stimulation by erythropoietin (Epo) requires Epo secretion

Erythropoietin (Epo) autocrine stimulation has been implicated in erythroblastic leukemia. To examine whether this stimulation could occur intracellularly, we developed Epo autocrine models of stimulation in the human pluripotent UT-7 cell line. Retroviral expression of Epo totally abolished the growth factor requirement of UT-7 cells. Autonomous proliferation was not cell density-dependent and occurred at a unicellular level, showing a genuine autocrine mode of stimulation. Total blockage of Epo secretion induced by the endoplasmic reticulum-retention amino acids Lys-Asp-Glu-Leu (KDEL) signals in 11 lines prevented autonomous proliferation, whereas a leaky retention system, observed in 3 other lines, resulted in limited autocrine stimulation without true long-term autonomous proliferation. Production of Epo, in contrast to KDEL-modified Epo, induced reductions in Epo binding, Epo receptor (EpoR) mRNA, and phosphorylation levels similar to those induced by the addition of exogenous Epo to the parental cell line. In addition, autonomous growth and survival were inhibited by the addition of Epo-neutralizing antibodies, affording evidence that autocrine stimulation through EpoR activation takes place on the cell surface. Finally, phenotypic analysis of the virus-infected clones indicated that Epo production did not change the differentiative capacities of UT-7 cells. All these data show that Epo autocrine stimulation is dependent on Epo secretion and takes place on the cell surface. From all analyzed parameters, the effects of Epo autocrine stimulation and those of exogenously added Epo appear to be identical.

Erroneous results of 3H-thymidine incorporation are related to position of thymidine residues in oligodeoxynucleotides

Antisense oligodeoxynucleotides (ODNs) targeted to complementary mRNA sequences have proved to be a powerful approach in assessing the function and the role of unique genes in cell proliferation, differentiation, or transformation. Despite their importance in the development of future therapies, little is known about their fate after uptake by cells. Here, we have examined the contribution of individual nucleotide residues from synthetic nonspecific ODNs on assays commonly used to measure cell proliferation. A dramatic decrease of the 3H-thymidine (3H-T) incorporation was obtained with nonspecific ODNs, while no effect on cell proliferation was observed as assessed by three other techniques. We demonstrate that the presence and position of thymidine in the ODNs directly interfere with the intracellular thymidine pool, leading to faulty data of 3H-T incorporation. As an alternative method, we used 3H-deoxyuridine (3H-dU), which is integrated more efficiently in DNA than thymidine. We observed that 3H-dU incorporation was also decreased. In conclusion, caution should be exercised in the interpretation of the results of 3H-T and 3H-dU incorporation in the presence of oligodeoxynucleotides.

Thrombocytopenia after bone marrow transplantation caused by a recipient origin Br(a) allo-antibody: presence of mixed chimerism 3 years after the graft without hematologic relapse

We report a case of mild, clinically asymptomatic, immune thrombocytopenia after allogenic bone marrow transplantation (BMT) for chronic myeloid leukemia (CML) caused by the presence of a recipient-origin Br(a) antibody that recognized the donor platelets. Although the antibody titer decreased, it remained detectable more than 3 years after BMT. Chimerism studies were performed combining cytogenetics, blood cell phenotype studies, and genomic amplification of hypervariable sequences. Cytogenetic studies and molecular analysis of peripheral blood cells, purified B- and T-lymphocyte subpopulations, and bone marrow colonies showed the hematopoiesis to be of donor origin, but absorption-elution experiments with peripheral RBCs showed a small amount of recipient RBCs. The CML chimeric transcript was also detected by means of polymerase chain reaction on samples collected until day +867 post-BMT. This case shows that recipient-origin platelet alloantibodies can cause thrombocytopenia after BMT and that the persistence of small numbers of recipient cells (even leukemic) is not necessarily associated with hematologic relapse.

Role of granulocyte-macrophage colony-stimulating factor, interleukin-3 and interleukin-5 in the eosinophilia associated with T cell lymphoma

We studied two patients with a leukaemic T cell lymphoma who presented with a marked increase in blood eosinophilia. To investigate the mechanism of the eosinophilia, supernatants of peripheral blood cells containing more than 80% lymphoma cells were tested by biological assays for the presence of colony stimulating factors (CSF). In one case supernatants stimulated the growth of granulocyte-macrophage (GM), erythroid and eosinophil colonies. These effects were neutralized by anti-GM-CSF antibodies; anti-IL5 antibodies slightly decreased eosinophil colony formation. Supernatants derived from the second patient cells stimulated the same lineages. Neutralizing experiments demonstrated that in addition to GM-CSF it contained interleukin 3 (IL-3) and interleukin 5 (IL-5). In agreement with the biological data, RNA studies using the polymerase chain reaction showed that cells from the first patient expressed GM-CSF transcripts; IL-5 transcripts were also detected in very low amounts. GM-CSF, IL-3 and IL-5 transcripts were detected in cells from the second patient. Thus eosinophilia associated with some T cell lymphoma is likely due to secretion of different combinations of cytokines by malignant cells.

Antioxidant defenses and its modulation by iron in carrageenan-induced inflammation in rats

The concentration of endogenous antioxidants has been studied in rats with a carrageenan-induced granuloma. This animal model of inflammation allowed us to study the antioxidant defenses and the oxidative stress in plasma and in the site of inflammation (exudate) and their modulation by the levels of iron in the organism after iron-dextran or desferrioxamine administration. In inflamed rats without supplementary treatment, an interrelation between urate, ascorbate and vitamin E levels has been observed and it appears to be an important mechanism to prevent the depletion of the antioxidants. Further, the sulphydryl groups, caeruloplasmin and retinol also contribute to the defense in this experimental model. Iron overload increases the production of malondialdehyde and decreases some antioxidants such as ascorbic acid and SH groups but, on the other hand, it raises the levels of urate and caeruloplasmin. However, the protective effect of desferrioxamine has not been observed, and in our conditions this may be due to the induced mobilization of iron. Our results show that antioxidants have an important role in the prevention of lipid peroxidation by free radicals produced during inflammatory processes. This protective effect depends on the stage of inflammation.

Expression of tal-1 and GATA-binding proteins during human hematopoiesis

Tal-1 rearrangements are associated with nearly 30% of human T acute lymphoblastic leukemia. Tal-1 gene encodes a putative transcription factor with a basic helix-loop-helix domain and is known to be predominantly expressed in hematopoietic cells. We investigated the pattern of tal-1 expression in purified human hematopoietic cells by in situ hybridization and reverse transcriptase polymerase chain reaction analysis. Both methods demonstrated that the tal-1 gene is expressed in megakaryocytes and erythroblasts as well as in basophilic granulocytes. In addition, our results indicate that the tal-1 1A promoter, which contains two consensus GATA-binding sites, is active mainly in these lineages. Because the GATA-1 gene is known to transactivate several genes specific for the erythroid, megakaryocytic, and mastocytic/basophilic lineages, we studied GATA-1 expression in these purified hematopoietic cells. We found that GATA-1 and tal-1 genes are coexpressed in these three lineages. Remarkably, the expression of both genes is downmodulated during erythroid and megakaryocytic terminal maturation. In immature hematopoietic cells, tal-1 and GATA-1 genes are coexpressed in committed progenitors cells (CD34+/CD38(2+)), whereas they are not detectable in the most primitive cells (CD34(2+)/CD38-). In contrast, GATA-2 is strongly expressed in both most primitive and committed progenitors cells, whereas GATA-3 is mostly detected in most primitive ones. Altogether our results strongly suggest that GATA-1 modulates the transcription of tal-1 during the differentiation of the erythroid, megakaryocytic, and basosophilic lineages.

Iron absorption by small intestine of chickens

Iron (Fe) absorption by three segments (duodenum, jejunum, and ileum) of the small intestine of chickens was studied by a perfusion technique in vivo in closed circuit using 59Fe Cl3 and was related to the histological characteristics of each segment. The serosal transfers of Fe for the duodenum and jejunum were the same (14%/cm), but significantly different (p < 0.05) from those of the ileum (9%/cm), which may be explained by the morphological and histological properties of the gut of chickens. However, the presence of Fe in blood and in liver was significantly lower after perfusion of the jejunum and ileum than after perfusion of the duodenum. It is concluded that chickens show an early adaptation of small intestine to Fe absorption in response to the considerable loss of Fe suffered during the laying process.

Granulocyte-macrophage colony-stimulating factor and erythropoietin act competitively to induce two different programs of differentiation in the human pluripotent cell line UT-7

The UT-7 cell line was established from a patient with a megakaryoblastic leukemia (Komatsu et al, Cancer Res 51: 341, 1991). Its proliferation is strictly dependent on the presence of hematopoietic growth factors including erythropoietin (Epo), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-3 (IL-3). We investigated the differentiation capacities of this cell line under the action of several growth factors, using immunomarkers, flow cytometry, and ultrastructural techniques. In the presence of GM-CSF and IL-3, eosinophil and basophil promyelocytes were detected, as well as a few cells with erythroid and megakaryocytic (MK) differentiation features. In contrast, Epo induced a marked erythroid differentiation with an increase of glycophorin A expression, accompanied by a few hemoglobinized cells. Differentiation induced by the growth factors took 24 to 48 hours to begin, and increased with cell passages to a plateau at 2 weeks of culture. However, this was not only due to a cell selection because the differential effects of Epo and GM-CSF were observed from a single cell clone and the phenotype could be reversed by opposite growth factors, even after a long period of culture. We subsequently investigated the phenotype of UT-7 in the presence of combinations of Epo, IL-3, and GM-CSF, and showed that GM-CSF and IL-3 act predominantly over Epo. This effect was mediated by a rapid downmodulation of Epo receptors by GM-CSF at messenger RNA and binding sites levels, without a change in receptor affinities. On the other hand, Epo had no effect on number and affinity of GM-CSF receptors. This study shows that UT-7 is a growth factor-dependent pluripotent cell line in which commitment may be directed by a hierarchical action of growth factors through an early and rapid transmodulation of growth factor receptors.

Expression of the serglycin gene in human leukemic cell lines

The expression of the human serglycin gene was determined in nine human leukemic cell lines, representing a spectrum of erythrocytic, megakaryocytic, monocytic, granulocytic, and lymphocytic potentialities. By Northern blot analysis, a 1.4 kb transcript was characterized in some of these cell lines, using a cDNA probe coding for human serglycin. Five of these cell lines, HEL, U-937, HL-60, K-562, and KU-812 were treated with phorbol myristic acetate to induce differentiation. Under these conditions the expression of the serglycin gene was modulated compared to the non-induced cells. HL-60, K-562, and KU-812 were also induced with dimethyl sulfoxide and retinoic acid; variations in serglycin transcript level were also observed. The present investigation establishes, at the nucleic acid level, the ability of various cells mimicking different stages in the developmental pathways of the haemopoietic lineage to synthesize proteoglycans belonging to the serglycin family. The results reported here led us to conclude that serglycin expression is closely associated with the haemopoietic cell differentiation pathway. The putative functions of serglycin in the haemopoietic system are briefly discussed.

Molecular cloning and characterization of MPL, the human homolog of the v-mpl oncogene: identification of a member of the hematopoietic growth factor receptor superfamily

We have cloned the human homolog of the v-mpl oncogene transduced in the myeloproliferative leukemia retrovirus, which presents striking homologies with members of the hematopoietin receptor superfamily. We obtained two types of clones, MPLP and MPLK, which had the same 5' extremity but differed at their 3' ends. The resulting deduced polypeptides are composed of a common extracellular domain with a putative signal sequence and a common transmembrane domain, but they differ in their cytoplasmic domain after a stretch of 9 common amino acids. The extracellular domain of MPL contains the consensus sequences described for the members of the hematopoietin receptor superfamily. In addition, as for murine interleukin 3 and human and murine granulocyte-macrophage colony-stimulating factor type beta receptors, this domain can be divided into two subunits. An additional motif specific for MPL could be displayed by hydrophobic cluster analysis in the first subdomain. When RNAs from various hematopoietic cell lines were analyzed by Northern blot, MPL was detected only in the human erythroleukemia (HEL) cell line as a major 3.7-kilobase (kb) mRNA (MPLP) and a minor 2.8-kb mRNA (MPLK). However, study of MPL expression by PCR analysis indicated that MPL is expressed at a low level in a large number of cells of hematopoietic origin and that the two types of mRNAs (P and K) were always found to be coexpressed.

Autocrine stimulation by erythropoietin and autonomous growth of human erythroid leukemic cells in vitro

Autonomous colony formation is a frequent event in erythroleukemia. In 13 cases of early erythroid leukemias, we investigated whether erythropoietin (Epo) autocrine stimulation was responsible for the growth factor autonomy. Epo transcripts were detected by Northern blotting in cells from one patient. These cells also expressed an Epo receptor (1,000 receptors per cell) with a 420-pM affinity and Epo was detected in the supernatant of cultured cells. In 8 of the 13 cases, Epo transcripts were revealed by the polymerase chain reaction ranging from 0.5 to 500 copies per cell. In situ hybridization proved that these Epo transcripts were present in the blast cells. No Epo gene abnormalities were detected by Southern blotting. In two cases, leukemic cells were grown in the presence of Epo-neutralizing antibodies or Epo antisense oligomers. In one case, the antibody significantly reduced autonomous growth. In contrast, the antibody had no effect in the second case in which blast cells transcribed the Epo gene at a low level. However, Epo antisense oligomers partially inhibited autonomous growth. This inhibition was reversed by addition of exogenous Epo. Overall, these results suggest that an extracellular or intracellular autocrine Epo stimulation occurs in some cases of erythroid malignancies.

Carrageenan-induced granuloma and iron status in rats with dietary polyunsaturated fatty acid deficiency

Sprague-Dawley rats were fed for 4 months on a control diet or a polyunsaturated-fatty-acid (PUFA)-deficient diet. The combined effects of iron overload (Fe dextran) or Fe deficiency (desferrioxamine) on carrageenan-induced granuloma were studied. PUFA deficiency induced changes in Fe metabolism, but no alterations in lipid peroxidation variables were observed. Inflammation implied an increase in lipid peroxidation, Fe storage and caeruloplasmin concentration, together with symptoms of anaemia. PUFA deficiency in inflamed rats gave rise to a lower inflammatory response (granuloma weight and prostaglandin E2 concentration) and ethane exhalation. Fe overload potentiated inflammatory and lipid peroxidation processes, whereas Fe deficiency decreased them.

Modulation of exudate inflammation parameters in rat carrageenan-induced granuloma by modification of exudate iron levels

We have used the carrageenan-induced pouch-granuloma in rats to investigate how changes in low-molecular-mass iron chelate levels in the exudate, induced by iron loading (iron-dextran) or chelation (desferrioxamine) influence cellular and systemic inflammatory parameters. In the iron-treated group we observed a rapid decrease in the number of leukocytes and exudate volume; there was also an increase in ferritin iron and low-molecular-mass iron chelates, and on the eighth day a systemic response. In the desferrioxamine-treated group we detected a decrease in low-molecular-mass iron chelates, ferritin iron, and an increase in the number of leukocytes. We describe the protective effects of desferrioxamine against the deleterious effects of ferrous iron and relate this to its chelating and scavenging activity. The results suggest that the levels of low-molecular-mass iron chelates modulate the inflammatory response, possibly through their contribution to the oxygen free radical generation, which is responsible for the cell membrane damage and subsequently its death. The modulatory action of iron-dextran and desferrioxamine support our hypothesis.

Expression of interleukin 6 and its specific receptor by untreated and PMA-stimulated human erythroid and megakaryocytic cell lines

Different human hematopoietic cell lines were analyzed for the presence of interleukin 6 (IL-6) and IL-6 receptor (IL-6-R). Both IL-6 mRNA and secreted active IL-6 protein were detectable in untreated cell lines with erythroid or megakaryoblastic features (K562, HEL, KU 812, MEG-01, and Dami), but they were not expressed constitutively in other leukemic cell lines (KG1, HL60, and U937). IL-6-R production, studied by the presence of its mRNA and specific binding sites for iodinated recombinant IL-6, was detected in most cell lines except K562, HEL, and Dami. Therefore, only KU 812 and MEG-01 coexpress both IL-6 and IL-6-R. After phorbol ester myristate acetate (PMA) treatment, all the cell lines studied expressed or overexpressed IL-6. In the erythroid K562 cell line, IL-6-R was not detectable before induction, but was promptly expressed after stimulation with PMA, suggesting that some of the new features of K562 cells induced by PMA may be mediated by IL-6. However, neutralizing antibodies against IL-6 did not block either the growth arrest or the loss of the erythroid phenotype induced by PMA. The presence of IL-6 and IL-6-R in erythroid and megakaryocytic leukemic cell lines suggests that their synthesis may occur during normal hematopoietic differentiation.

Sexual and age variations of organ iron content in Shaver chickens

1. Haematological values and iron content in liver, spleen, kidneys and intestine were determined in Shaver chickens of both sexes at 4, 8, 13 and 18 weeks and in females at 24 weeks (the beginning of the laying period). 2. The haematocrit decreased significantly in laying compared with non-laying females and the haemoglobin concentration was similar to that in the prelaying state. Plasma iron in laying females increased to four times the basal value at 13 weeks. 3. Females of 13 and 18 weeks (prelaying state) stored more iron than males at the same age. A simultaneous liver and spleen mobilisation of stored iron and increased intestinal iron accumulation took place in the laying process. The haematological variables examined were minimally altered. 4. The iron contents of both heart and kidneys were influenced by age and followed a linear trend, except that in the heart of females where a quadratic response was observed.

An ubiquitous isoform of glycophorin C is produced by alternative splicing

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Organ iron content in New Hampshire chickens

We have studied some hematological parameters and iron and ferritin iron contents in different organs of New Hampshire chickens at the ages of 4, 8, 13, and 18 wk for both sexes, as well as 24 wk for laying hens, in order to study the variations with age, the existence of sex differences, and the accommodations to laying. The hematocrit and hemoglobin levels did not show important variations, but plasma iron increased at laying. The iron and ferritin iron concentrations in liver and spleen increased more slowly during growth than the total iron and ferritin iron contents, and no significant decline was observed at laying. The iron concentration in the heart and pectoral muscle stayed constant throughout the period studied, and kidneys showed slight increase with age. However, the iron concentration in the intestine decreased from the proximal to the distal segments and also increased in the duodenum at laying. No differences caused by sex have been detected in the organs studied. The absence of differences caused by sex in the organ iron stores in favor of females, especially in liver, and the lack of influence of the laying process in iron stores could be a consequence of the low laying frequency of this strain.

Role of iron in carrageenan-induced granuloma: action of desferrioxamine and indometacin

Iron has been implicated in the inflammatory process. In this paper we studied the modulating inflammatory activity of iron in the carrageenan-induced granuloma pouch, taking indometacin as a standard anti-inflammatory drug. Sprague-Dawley rats were injected subcutaneously with desferrioxamine (100 mg/kg) and indometacin (5 mg/kg) for 3 consecutive days before granuloma induction, followed by a daily administration in the granuloma pouch until the day before death. We determined the granuloma weight and assayed in the exudate: volume, number of leukocytes, PGE2 levels and loosely bound iron content at 1 (acute inflammation) and 6 days (chronic inflammation) after granuloma induction. Our results show a dual effect of desferrioxamine, inflammatory in the acute phase and anti-inflammatory in the chronic phase. These results are discussed in relation to chemotaxis and to the potential role of iron on oxygen free radical production, collagen synthesis and hydroperoxide generation, while indometacin acts through the cyclooxygenase pathway.

In vitro kinetics of the oxidative reactivity of nitrate and nitrite in the rat erythrocyte

Isolated rat erythrocytes were incubated in the presence of nitrate and nitrite. Glucose, lactate, reduced glutathione, methaemoglobin, malondialdehyde and Na+/K+ membrane exchange were investigated. Nitrite induced a strong methaemoglobinaemia and a net depletion of reduced glutathione in the intracellular medium associated with membrane lipid peroxidation. This oxidative reactivity induced by nitrate and nitrite altered the cell's ionic flux.

Structure of the promoter region and tissue specificity of the human glycophorin C gene

Glycophorin C (GPC) is an integral membrane protein of human erythrocytes which plays an important role in regulating the deformability and mechanical stability of red cells. Recently, the structural gene for this glycoprotein has been cloned (Colin, Y., Le Van Kim, C., Tsapis, A., Clerget, M., d'Auriol, L., London, J., Galibert, F., and Cartron, J. P. (1989) J. Biol. Chem. 264, 3773-3780), and we have now determined the sequence of the 1050 base pairs of DNA preceding the transcription initiation site mapped in erythroid cells. This region contains different potential regulatory cis-acting elements found in a variety of eukaryotic promoters (TATA box, CAAT box, Sp1-binding site) as well as sequences present in the promoter and enhancer regions of genes specific for the erythroid lineage (CACCC box and NF-E1-binding site). Northern blot analysis and immunological studies indicate that the GPC gene is expressed in a large number of cells and tissues. However, the level of transcription as well as the glycosylation of the mature GPC differ in erythroid and nonerythroid cells. Primer extension analysis and mapping of the 5' end GPC mRNA by the polymerase chain reaction indicate that different transcription sites are utilized for the expression of the GPC gene in erythroid and nonerythroid tissues and cell lines.