Iron-fortified and unfortified cow's milk: effects on iron intakes and iron status in young children.

UNLABELLED: Iron intakes and iron status were evaluated in 36 young Swedish children given either iron-fortified or unfortified cow's milk. All children had good iron status and had received breast milk or iron-fortified formulae during infancy. Twenty 1-y-old children were randomized to a diet with iron-fortified milk (7.0 or 14.9 mg Fe l(-1) and 16 to a diet with unfortified milk. The iron intakes in the unfortified group at 15 and 18 mo (mean +/- SD 5.19 +/- 2.29 and 5.84 +/- 1.62 mg d(-1)) were low in relation to Nordic Nutrition Recommendations, while the intakes in the iron-fortified group (10.20 +/- 2.60 and 10.87 +/- 2.79mg d(-1)) were normal in relation to recommendations. The gain (increase) from receiving fortified diet during the study period was at most [upper limit for 95% confidence interval (CI)] 2.6 g l(-1) in blood haemoglobin, 1.9 fl in mean corpuscular volume, 2.7 micromol in serum iron and 4.5% in transferrin iron saturation, and the gain (decrease) was at most (lower limit for 95% CI) 0.29g l(-1) in serum transferrin and 0.9mg l(-1) in serum transferrin receptor (TfR). None of these differences was statistically significant. There was an almost significantly higher increase in serum ferritin (1.4 times higher relation of values at the end compared with the beginning, p = 0.06) and a significantly higher (1.2; p = 0.047) decrease in TfR/ log10 ferritin ratio in the fortified group. CONCLUSION: One-year-old children starting out with good iron status given either iron-fortified or unfortified cow's milk from 12 to 18 mo maintain sufficient iron status during this period. However, children fed unfortified cow's milk have an iron intake which is low in relation to recommendations and the quantitative development of their reserve iron in iron stores seems to be weaker than that of the fortified group. The consequences of this require further study.

An automatic incision device for obtaining blood samples from the heels of preterm infants causes less damage than a conventional manual lancet.

OBJECTIVES: To evaluate in a randomised blind study the effect on puncture site lesions of two different incision devices used to obtain blood samples from preterm infants by repeated heel sticks. SETTING: The neonatal intensive care unit at the Hospital for Children and Adolescents and Laboratory, Helsinki University Central Hospital. PATIENTS: A total of 100 preterm infants (birth weight below 2500 g) not previously subjected to heel stick sampling. INTERVENTIONS: The infants were randomly allocated to blood sampling from the heel with either a conventional manual lancet or an automatic incision device. The same type of lancet was used for any given baby throughout the study (2-21 days). MAIN OUTCOME MEASURES: The damage caused by sampling was evaluated using four criteria: bruising of the heel, inflammation of the heel, bruising of either the ankle or the leg, and skin healing at the puncture site. The evaluation was based on photographs presenting typical categories of each outcome. RESULTS: To obtain a sufficient volume of blood, on average 2.6 times more punctures were needed when the conventional manual lancet was used than when the automatic incision device was used. Heels punctured with the lancet had more bruising (100% v 84%) and more signs of inflammation (79% v 53%), and there was more bruising of the ankle or leg (92% v 53%) than when the automatic incision device was used. Skin healed equally rapidly in the two groups. CONCLUSION: The use of an automatic incision device for collecting repeated skin puncture samples from preterm infants is less traumatic than the use of a conventional manual lancet.

Antiestrogens reduce plasma levels of endothelin-1 without affecting nitrate levels in breast cancer patients.

Tamoxifen protects against myocardial infarction through mechanisms that are poorly understood. We studied the effects of tamoxifen and another antiestrogen, toremifene, on the production of vasoconstrictive endothelin-1 and of vasodilatory nitric oxide in 44 postmenopausal patients with breast cancer. These started treatment, in randomized order, with either tamoxifen (20 mg/day; n = 25) or toremifene (40 mg/day; n = 19). Plasma samples collected before treatment and after 6 and 12 months of both regimens were assayed for endothelin-1 with a specific radioimmunoassay and for nitrite/nitrate with a method based on the Griess reaction. The antiestrogen group as a whole showed a fall in endothelin-1 at 6 months (5.9 +/- 3.3%; p = 0.06) (mean +/- SE) and at 12 months (7.1 +/- 5.5%; p = 0.03). This fall was solely due to toremifene, the use of which was associated with falls in endothelin-1 at 6 months (12.9 +/- 4.7%; p = 0.01) and 12 months (9.2 +/- 6.2%; p = 0.06). The antiestrogen regimen failed to affect plasma nitric oxide significantly but nevertheless the ratio between nitric oxide and endothelin-1 rose by 31.6 +/- 13.3% at 6 months and by 35.6 +/- 15.3% at 12 months in the antiestrogen users, an effect similar in the tamoxifen and toremifene groups. We conclude that antiestrogens may protect against myocardial infarction by preventing the release of endothelin-1 and by shifting the balance between nitric oxide and endothelin-1 to the dominance of the former. Our data predict that toremifene and tamoxifen at the doses studied here will provide similar cardiovascular protection.

Platelet dysfunction after intravenous ketorolac or propacetamol.

BACKGROUND: Paracetamol is a weak cyclo-oxygenase inhibitor in vitro. A recent study in children has shown that high doses of paracetamol are effective and safe. We studied the effect of propacetamol on haemostasis in adult volunteers. METHODS: Ten volunteers were investigated in a double-blind, randomized, crossover study. They received propacetamol 60 mg kg(-1) or ketorolac 0.4 mg kg(-1) in saline i.v. (30 min) in two different sessions. Platelet function was evaluated before the test infusion (S-0), two (S-2) and 24 h (S-24) after the start of the infusion. Coagulation parameters (PT, APTT, factor V and VII activities) were measured at S-0, S-24 and 48 h (S-48). RESULTS: One of the volunteers had no secondary platelet aggregation in S-0 and was excluded from the final analysis. Two hours (S-2) after propacetamol and ketorolac administration the adrenaline (0.9 microg ml(-1) and 9.0 microg ml(-1)) induced maximal platelet aggregation was decreased compared with S-0. At S-2 platelet aggregation was inhibited more after ketorolac than after propacetamol. At 24 h after ketorolac, but not after propacetamol, there was still a decrease in the adrenaline-induced maximal platelet aggregation. Propacetamol did not affect adenosine diphosphate (ADP)-induced maximal platelet aggregation, whereas ketorolac decreased 3 and 6 microM ADP-induced maximal platelet aggregation at S-2 and S-24. However, 2 h after both ketorolac and propacetamol, thromboxane B2 (TxB2) concentration decreased in platelet rich plasma after 5 min aggregation induced by 8 microM ADP. Coagulation was unaffected. CONCLUSION: Propacetamol 60 mg kg(-1) i.v. causes reversible platelet dysfunction demonstrated by a decrease in maximal platelet aggregation and TxB2 concentration. After 0.4 mg kg(-1) ketorolac i.v. platelet aggregation and TxB2 formation are inhibited more in comparison with propacetamol, and platelet dysfunction is still seen after 24 h.

Administration of transdermal estrogen without progestin increases the capacity of plasma and serum to stimulate prostacyclin production in human vascular endothelial cells.

OBJECTIVE: To determine whether transdermal hormone replacement therapy modifies the ability of plasma or serum to regulate the synthesis of prostacyclin and that of endothelin-1 by cultured human umbilical vein endothelial cells. DESIGN: Prospective, randomized study. SETTING: Department of Obstetrics and Gynecology, Helsinki University Central Hospital. PATIENT(S): Thirteen postmenopausal women with climacteric symptoms. INTERVENTIONS: Transdermal 17beta-E2 (50 microg/d) continuously combined with norethisterone acetate, (250 microg/d) on days 15-28 of the treatment cycles for 6 months. MAIN OUTCOME MEASURE(S): Levels of prostacyclin's metabolite 6-keto-prostaglandin F1alpha and of endothelin-1 released by cultured human umbilical vein endothelial cells. RESULT(S): Plasma and serum during the E2-only phase of hormone replacement therapy enhanced prostacyclin production by 20% +/- 8% (mean +/- SEM) and 23% +/- 11%, respectively. Plasma or serum taken during the E2 + norethisterone acetate phase failed to affect prostacyclin production. Hormone replacement therapy induced no change in the capacity of plasma or serum to release endothelin-1. CONCLUSION(S): Transdermal hormone replacement therapy during the E2-only phase increased the capacity of plasma and serum to enhance production of vasoprotective prostacyclin in human vascular endothelial cells, without affecting production of endothelin-1. Addition of norethisterone acetate prevented this stimulation.

Effects of tamoxifen and toremifene on urinary excretion of pyridinoline and deoxypyridinoline and bone density in postmenopausal patients with breast cancer.

Tamoxifen and toremifene are two mostly used antiestrogens in the treatment of breast cancer. To compare their effect on bone in postmenopausal breast cancer patients we measured the urinary output of two bone resorption markers, pyridinoline (Pyr) and deoxypyridinoline (Dpyr) as well as bone density (BMD) in 30 breast cancer patients using either tamoxifen (20 mg/day, n = 15) or toremifene (40 mg/day, n = 15) as adjuvant treatment of stage II breast cancer for 1 year. The urinary output of Pyr and Dpyr were assessed before and after 6 and 12 months of the antiestrogen regimen. Lumbar and femoral BMD were measured by dual energy X-ray absorptiometry (DXA) before and after 12 months of treatment. Both tamoxifen and toremifene were associated with significant decreases in Pyr (mean fall 19.6% and 12.6%, respectively) and Dpyr (mean fall 21.6% and 15.5%, respectively) at 6 months. After 12 months' treatment, Pyr decreased by 30.8% and Dpyr by 21.2% in women using tamoxifen and significantly less in women using toremifene (10.1% and 4.9%, respectively). BMD in the lumbar spine decreased by 1.8% in the toremifene group but increased by 0.4% in the tamoxifen group; in the proximal femur, BMD increased slightly during both tamoxifen and toremifene treatment in all sites measured. Individual changes in Pyr and Dpyr at 6 months showed no significant relation to the change in BMD at 12 months. We conclude that tamoxifen (20 mg/day) and toremifene (40 mg/day) reduce the bone resorption similarly, and this can be detected by falls in urinary output of Pyr and Dpyr at 6 months of treatment.

Human vascular endothelial cells produce tumor necrosis factor-alpha in response to proinflammatory cytokine stimulation.

OBJECTIVE: To determine whether human vascular endothelial cells produce tumor necrosis factor-alpha (TNF-alpha) after stimulation with proinflammatory cytokines and bacterial lipopolysaccharides (LPS). DESIGN: Prospective, in vitro repeated-measurements analysis of cellular responses. SETTING: Research laboratory in an academic medical center. SUBJECTS: Human umbilical vein endothelial cells (HUVECs). INTERVENTIONS: HUVECs were incubated with interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), and LPS, or their different combinations for 2 to 48 hrs. MEASUREMENTS AND MAIN RESULTS: TNF-alpha was measured by time-resolved immunofluorometric assay. Unstimulated HUVECs did not produce detectable amounts of TNF-alpha, but IFN-gamma, IL-1beta, and LPS when added together induced TNF-alpha production of HUVECs in a time-dependent manner. Immunofluorescent staining confirmed that the TNF-alpha was produced by endothelial cells. IFN-gamma, IL-1beta, or LPS alone did not induce TNF-alpha production, whereas IFN-gamma and IL-1beta in combination were able to induce TNF-alpha production to some extent, and the production could be further increased with LPS. TNF-alpha messenger RNA expression was detected with reverse transcriptase-coupled polymerase chain reaction in stimulated, but not in unstimulated, HUVECs. CONCLUSIONS: HUVECs are capable of producing TNF-alpha after proinflammatory cytokine stimulation and may therefore contribute to the increased amount of TNF-alpha found in pathologic states such as septic shock.

Vascular endothelial growth factor in human preterm lung.

Endothelial cell damage is characteristic for respiratory distress syndrome and development of chronic lung disease. Vascular endothelial growth factor (VEGF) is an endothelial mitogen that takes part in the growth and repair of vascular endothelial cells. We measured VEGF in 189 tracheal aspirate samples (TAF), and in 24 plasma samples from 44 intubated preterm infants (gestational age, 27.3 +/- 2.0 wk; birth weight, 962 +/- 319 g) during their first postnatal week. VEGF in TAF increased from 25 +/- 12 pg/ml (mean +/- SEM) on Day 1 to 526 +/- 120 pg/ml on Day 7 (mean concentrations, 106 +/- 25 pg/ml on Days 1 to 3 and 342 +/- 36 pg/ml on Days 4 to 7). In plasma, mean concentration of VEGF during the first week was 48 +/- 6 pg/ml, with no increase observed. In TAF, higher VEGF was found in patients born to mothers with premature rupture of the membranes, or chorionamnionitis, whereas preeclampsia of the mother was associated with lower VEGF (all p < 0.05). In TAF, no correlations existed between VEGF and gestational age or birth weight, but a correlation existed between lecithin/sphengomyelin ratio and VEGF (p < 0.05). During Days 4 to 7 patients developing bronchopulmonary dysplasia (BPD) had lower VEGF in TAF than did those surviving without BPD (235 +/- 31 versus 383 +/- 50; p < 0.05). VEGF increased rapidly in the lungs of the preterm infant during the first days of life. VEGF may be indicative of pulmonary maturity and may participate in pulmonary repair after acute lung injury.

Plasma homocysteine levels elevated and inversely related to insulin sensitivity in preeclampsia.

OBJECTIVE: To study the plasma levels of homocysteine in preeclampsia and relate them to insulin sensitivity. METHODS: In association with a 3-hour intravenous glucose-tolerance test (glucose 0.3 g/kg at 0 and 0.03 IU insulin 20 minutes later), we measured plasma levels of homocysteine, vitamin B12, and folic acid in 22 women with preeclampsia and 16 controls between 29 and 39 weeks' gestation. In 14 women with preeclampsia and 11 controls, plasma samples also were collected 3 months after delivery. RESULTS: Levels of homocysteine in women with preeclampsia (6.7 +/- 0.4 micromol/L, mean +/- standard error) were higher (P < .001) than those in controls (3.8 +/- 0.2 micromol/L) and related significantly to the level of proteinuria (r = .49, P = .02). Vitamin B12 concentrations were lower in women with preeclampsia (166.0 +/- 10.4 compared with 212.4 +/- 16.4 pmol/L, P = .02), whereas levels of folic acid showed no difference between the groups. After delivery, levels of homocysteine increased to 9.1 +/- 0.6 and 8.2 +/- 0.6 micromol/L in women with preeclampsia and controls, vitamin B12 increased to 298.8 +/- 28.6 compared with 334.9 +/- 24.0 pmol/l, and folic acid decreased to 10.6 +/- 2.0 compared with 7.9 +/- 0.8 nmol/L, with no difference emerging between the groups. In women with preeclampsia but not in controls, plasma homocysteine was negatively related to insulin sensitivity (r = -.51, P = .02). The mean 2.9-fold increase in glucose or 52.5-fold increase in insulin during the insulin-sensitivity test failed to affect homocysteine levels. CONCLUSION: Women with preeclampsia have high plasma homocysteine levels that are inversely related to insulin sensitivity.

Nitric oxide production with preeclampsia.

OBJECTIVE: To clarify production of nitric oxide with pre-eclampsia. METHODS: Production of nitric oxide and elimination of its metabolites, nitrite and nitrate, determines ultimately the level of those metabolites in plasma of subjects whose diets lack them. We measured simultaneously plasma levels and renal clearance of nitrite and nitrate in 20 women with preeclampsia and in 21 healthy pregnant women. Fifteen preeclamptic gravidas were receiving antihypertensive medication and five received betamethasone 1-4 days before the study. Subjects were prescribed low nitrite and nitrate diets for 24 hours and fasted overnight before collection of plasma and urine samples. Nitrite and nitrate were measured spectrophotometrically by Griess reaction. RESULTS: Preeclamptic women had significantly higher plasma levels of nitrite and nitrate (18.1+/-6.2 micromol/L versus 13.0+/-4.3 micromol/L, mean+/-standard deviation [SD], P = .009), which because renal clearance did not differ (0.6+/-0.3 versus 0.7+/-0.3 mL/s), indicated increased production of nitric oxide with preeclampsia that was unaffected by antihypertensives or betamethasone. The mean plasma level of endothelin-1 was increased (5.1+/-1.4 versus 3.6+/-1.0 pg/mL, P < .001), and urinary output of the prostacyclin metabolite 2,3-dinor-6-keto-prostaglandin F1alpha was decreased (39.1+/-18.0 versus 61.3+/-35.6 ng/mmol creatinine, P = .019) with preeclampsia. These two endothelial markers showed no relation to plasma nitrite and nitrate. CONCLUSION: Nitric oxide production was increased with preeclampsia. The biologic significance of increased production is unknown, but it might be compensation for the vasoconstriction of preeclampsia.

Oral iron is sufficient for erythropoietin treatment of very low birth-weight infants.

UNLABELLED: The aim of this study was to compare two different doses and means of administration of iron in recombinant human erythropoietin (rHuEPO)-treated very low birth-weight (VLBW) infants. VLBW infants (n = 41) were randomized to one of three groups. Fourteen infants were treated with rHuEPO (300 IU/kg three times a week s.c.) and oral iron (ferrofumarate, 6 mg of iron/kg per day). Another 14 infants received the same erythropoietin dose and intramuscular iron (ferroxypolymaltose, once 12 mg of iron/kg weekly). Thirteen infants were treated with the same dose of intramuscular iron but did not receive rHuEPO. After the 3-week study period, haemoglobin concentrations and reticulocyte counts were similar in the rHuEPO-treated groups and both were higher than in the group not receiving rHuEPO (P < 0.001). In both rHuEPO-treated groups the transferrin receptor concentration increased from 6.8-7.2 mg/l to 10.5-11.3 mg/l. CONCLUSION: In erythropoietin-treated very low birth weight infants the iron need for erythropoiesis can be met by oral administration of iron.

Higher concentrations of serum transferrin receptor in children than in adults.

BACKGROUND: The serum transferrin receptor (TfR) concentration in adults is suggested to provide a sensitive measure of iron depletion and together with the serum ferritin concentration to indicate the entire range of iron status, from iron deficiency to iron overload. However, little is known about TfR concentrations in children. OBJECTIVE: Our objective was to compare serum TfR and ferritin concentrations and their ratios in children and adults and look for correlations between TfR concentrations and other measures of iron status. DESIGN: Our study groups were healthy 1-y-old infants (n = 36), 11-12-y-old prepubertal boys (n = 35), and 20-39-y-old men (n = 40). RESULTS: TfR concentrations were higher in infants (x; 95% reference interval: 7.8 mg/L; 4.5, 11.1) than in prepubertal boys (7.0 mg/L; 4.7, 9.2) and higher in prepubertal boys than in men (5.8 mg/L; 3.1, 8.5). Geometric mean TfR-ferritin ratios were higher in infants (316; 95% reference interval: 94, 1059) than in prepubertal boys (219; 78, 614) and higher in prepubertal boys than in men (72; 23, 223). By multiple linear regression analysis, the best predictors of TfR concentration were serum iron (P = 0.004) and log serum ferritin (P < 0.0001), both being inverse correlations (R2 = 0.32). Mean corpuscular volume, blood hemoglobin, transferrin iron saturation, transferrin, and even age seemed to not have an influence on the TfR concentration and erythropoiesis was not a determinant of TfR concentration. CONCLUSIONS: Low serum ferritin and iron concentrations, even within the normal physiologic range, result in high TfR concentrations. The lower the iron stores, the stronger the influence of ferritin on TfR. A high TfR concentration in children, especially in infants, is a response to physiologically low iron stores. Age-specific reference concentrations for TfR are needed.

Involvement of thromboxane A2 and prostacyclin in the early pulmonary hypertension after porcine meconium aspiration.

Severe perinatal aspiration of meconium is frequently complicated by unsuccessful neonatal adaptation with associated pulmonary hypertension. This vascular complication is supposedly related to pulmonary release of vasoconstrictory agents, including metabolites of arachidonic acid. Thus, to investigate the role of prostanoids on these meconium-induced circulatory changes in the lungs, the hemodynamic response to meconium instillation was studied in acetylsalicylic acid-pretreated juvenile pigs. Twelve 10-wk-old pigs with adapted lung circulation received 3 mL/kg of 65 mg/mL human meconium via the endotracheal tube. Six of them were medicated with 10 mg/kg acetylsalicylic acid 30 min before meconium insufflation. Hemodynamic parameters and urinary excretion of stable metabolites of thromboxane A2 and prostacyclin were measured serially for 6 h after the insult. Meconium administration induced a biphasic increase in mean pulmonary artery pressure and pulmonary vascular resistance, and a rapid rise in urinary levels of prostanoid metabolites. Acetylsalicylic acid pretreatment prevented the initial (0-1 h) pulmonary hypertensive response and increase in prostanoid excretion. During the second phase (1-6 h), acetylsalicylic acid did not attenuate the progressive increase in mean pulmonary artery pressure and pulmonary vascular resistance nor did it affect the longitudinal distribution of the pulmonary resistances. Our results thus show that in adapted porcine lungs, arachidonic acid metabolites contribute to the early hypertensive response, but have only minor effects during the second phase vascular hypertension.

Reduced viability of human vascular endothelial cells cultured on Matrigel.

Optimal vascular homeostasis requires efficient control of both proliferation and elimination of vascular endothelial cells. Programmed cell death, or apoptosis, is the main mechanism controlling cell elimination, and it is an essential component of vascular formation. Human vascular endothelial cells die in vitro, if prevented from obligatory survival factors like growth factors or attachment and cell spreading, but very little is known about the mechanisms controlling endothelial cell elimination. Signaling from the extracellular matrix affects the behavior and functions of human umbilical vein endothelial cells (HUVECs), and we have recently demonstrated the beneficial effects of plating on the reconstituted extracellular matrix Matrigel, on the inducible nitric oxide production of freshly isolated HUVECs. In this work we observed that cultured HUVECs formed typical capillary-like structures on Matrigel, but unexpectedly, after 24-48 hours their viability was gradually lost. Viability was measured with an assay based on mitochondrial reduction of reagent XTT. No decrease in viability was seen in freshly isolated HUVECs or in cultured fibroblasts during this time. It is known that cells often turn into apoptosis if they receive conflicting information from their surroundings, and apparently signaling from Matrigel to HUVECs, while at their in vitro proliferating phenotype, resulted in launching of the apoptotic machinery. Thus, proliferating and differentiated phenotypes of endothelial cells seemed to have different sensitivity to signals that induce apoptosis.

Estrogen and postmenopausal estrogen/progestin therapy: effect on endothelium-dependent prostacyclin, nitric oxide and endothelin-1 production.

It is well documented that postmenopausal estrogen/progestin therapy (HRT) protects women against cardiovascular disorders. However, the mechanism(s) by which this protection is mediated remains largely unresolved, because beneficial effects of estrogen on the blood lipid profile account for only 20-30% of the overall protection. Growing evidence suggests that estrogen has direct effects on the blood vessel wall indicating that vascular endothelium may play a key role in mediating these effects by producing vasoactive factors, such as prostacyclin (PGI2), nitric oxide (NO) and endothelin-1 (ET-1). In vitro estrogen stimulates endothelial PGI2 and NO production, whereas ET-1 production is not affected. Moreover, in vivo studies indicate that estrogen and HRT increase PGI2 and NO production, whereas ET-1 production decreases. These effects are evidently mediated through estrogen receptors in endothelial cells. Thus, estrogen and HRT lead to the dominance of vasodilatory and antiaggregatory agents released by the endothelial cells. This may be an important new mechanism in the cardiovascular protection mediated by estrogen and HRT.

The long-term effects of oral and transdermal postmenopausal hormone replacement therapy on nitric oxide, endothelin-1, prostacyclin, and thromboxane.

OBJECTIVE: Oral postmenopausal hormone replacement therapy (HRT) decreases the risk of cardiovascular disorders, but the mechanisms of this protection are largely unknown. We compared the long-term effects of sequential oral HRT and transdermal HRT on vasodilatory nitric oxide and prostacyclin as well as vasoconstrictive endothelin- and thromboxane A2, all of which may be factors in the protective effect of HRT against cardiovascular disorders. DESIGN: Prospective, randomized study. SETTING: Department of Obstetrics and Gynecology at a university hospital. PATIENT(S): Fifty-two healthy postmenopausal female nonsmokers (n = 42) or smokers (n = 10) who had climacteric symptoms. INTERVENTION(S): The women received either oral HRT (2 mg of estradiol on days 1-12, 2 mg of estradiol plus 1 mg of norethisterone acetate on days 13-22, and 1 mg of estradiol on days 23-28; n = 21) or transdermal HRT (50 microg/d of estradiol on days 1-28 followed by 250 microg/d of norethisterone acetate on days 14-28; n = 21) for 1 year. Ten female smokers received transdermal HRT for 1 year. MAIN OUTCOME MEASURE(S): Plasma levels of nitrate as an index of nitric oxide production, endothelin-1, and urinary output of the prostacyclin metabolite (2,3-dinor-6-keto-PGF1alpha) and that of the thromboxane A2 metabolite (2,3-dinorthromboxane B2) were measured before and during the combined phases of the 2nd, 6th, and 12th treatment months. RESULT(S): Both regimens increased plasma estradiol levels and alleviated vasomotor symptoms. Neither regimen caused significant changes in nitrate, endothelin-1, prostacyclin, or thromboxane A2 in nonsmoking women. Female smokers had significantly higher levels of endothelin-1, which were significantly reduced by transdermal HRT at 6 months of treatment. CONCLUSION(S): Nitric oxide, endothelin-1, prostacyclin, and thromboxane A2 are not of primary importance in the protective effect of sequential oral HRT against cardiovascular disorders in otherwise healthy nonsmoking postmenopausal women. In this regard, transdermal HRT appears comparable to oral HRT. Postmenopausal female smokers have high levels of endothelin-1 that are reduced by transdermal HRT.

Does glutamate mediate brain damage in acute encephalitis?

Cerebrospinal fluid (CSF) amino acid neurotransmitter concentrations in 23 patients with acute encephalitis were compared with those in patients with acute brain infarction, multiple sclerosis and controls. The concentration of glutamate was significantly higher in encephalitis (5.2+/-6.7 micromol/l) and stroke patients (9.6+/-14.2 micromol/l) than in MS patients (1.6+/-0.9 micromol/l) and controls (1.7+/-0.8 micromol/l; p < 0.001). The concentration of glycine was significantly higher in encephalitis (11.0+/-4.7 micromol/l) than in stroke (7.6+/-3.2 micromol/l) and MS patients (6.3+/-2.1 micromol/l) or controls (5.6+/-1.8 micromol/l; p < 0.002). Taurine levels were significantly lower in encephalitis patients than in the other groups (p = 0.04). The correlation of high glutamate levels with poor outcome was almost significant (Kendall tau 0.63, p = 0.06). Our observations suggest that exicitotoxic neurotransmission may play an important role in the series of events that lead to neuronal damage in encephalitis.

Evidence of high circulating testosterone in women with prior preeclampsia.

Women with prior preeclampsia are characterized by hyperinsulinemia and a 2- to 3-fold excess risk of hypertension and ischemic heart disease in later life. We therefore studied whether these women present changes in pituitary, ovarian, and endothelial factors that could also affect the risk of vascular disorders. Twenty-two women with prior preeclampsia and 22 control women matched by age and body mass index were studied an average of 17 yr after delivery. Women with prior preeclampsia had elevated serum free testosterone levels (20.6 +/- 2.2 vs. 15.0 +/- 1.3 pmol/L, mean +/- SE, P = 0.03), an elevated free androgen index (3.2 +/- 0.5 vs. 1.9 +/- 0.2, P = 0.04), and an elevated free testosterone estradiol ratio (0.089 +/- 0.017 vs. 0.046 +/- 0.006, P = 0.02). The levels of insulin-like growth factor binding protein-1 decreased as expected during a 3-h oral glucose tolerance test without differences between the groups. Levels of FSH, LH, androstenedione, dehydroepiandrosterone sulfate, and endothelin-1, as well as urinary output of prostacyclin and thromboxane A2 metabolites, showed no difference between study groups. A history of preeclampsia an average of 17 yr earlier thus appears to be associated with elevated levels of testosterone, which may contribute to the increased risk of vascular morbidity in such women.

Evaluation of an ELISA test for determination of the serum transferrin receptor. Demonstration of discordance between results obtained with two methods.

We undertook this study to evaluate a recently introduced ELISA kit for determining serum transferrin receptor (TfR) concentration (TfR, Ramco Laboratories, Inc.), to produce reference values for healthy adults, and to compare the results with another commercially available reagent system. The mean (SD) recovery of added TfR was 88% (6%). In dilution studies, the ratio between the measured and expected values was 0.98 (0.11). The intra-assay and interassay coefficients of variation were from 5% to 7% and from 6% to 9% in a physiological and a supraphysiological concentration range, respectively, and from 13% to 16% in a subnormal concentration range. In healthy adults between 20 and 60 years of age, we observed no age- or sex-related differences in TfR values. Thus, the same reference interval, 3.0-8.2 mg l(-1), may be used for this population. The correlation between the results obtained with the Ramco TfR test and the Amgen Diagnostics Clinigen test was satisfactory (r=0.79). The Ramco TfR test produced higher values (Tf=0.40 (-0.45-1.25)+1.46 (1.16-1.75)* Clinigen). The number of samples that fell within the same concentration interval with both methods (low, normal or high in relation to the respective reference interval) was only 45% (27/60). The Ramco TfR test had fewer values falsely suggesting iron deficiency than the Clinigen test. Serum TfR methods need to be uniformly standardized.