The Fe-FeSi phase diagram at Mercury's core conditions.

Mercury's metallic core is expected to have formed under highly reducing conditions, resulting in the presence of significant quantities of silicon alloyed to iron. Here we present the phase diagram of the Fe-FeSi system, reconstructed from in situ X-ray diffraction measurements at pressure and temperature conditions spanning over those expected for Mercury's core, and ex situ chemical analysis of recovered samples. Under high pressure, we do not observe a miscibility gap between the cubic fcc and B2 structures, but rather the formation of a re-entrant bcc phase at temperatures close to melting. Upon melting, the investigated alloys are observed to evolve towards two distinct Fe-rich and Fe-poor liquid compositions at pressures below 35-38 GPa. The evolution of the phase diagram with pressure and temperature prescribes a range of possible core crystallization regimes, with strong dependence on the Si abundance of the core.

Novel experimental setup for megahertz X-ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X-ray Free-Electron Laser (EuXFEL).

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

[Pro-hepcidin, its relation with indicators of iron metabolism and of inflammation in patients hemodialyzed treated or not with recombinant erythropoietin]. / Pro-hepcidina, su relación con indicadores del metabolismo del hierro y de inflamación en pacientes hemodializados tratados o no con eritropoyetina recombinante.

UNLABELLED: Hepcidin, an antimicrobial peptide which synthesis is regulated by iron status and inflammation, plays an important role in iron homeostasis in hemodialysed (HD) patients. It is measured by measuring serum prohepcidin. OBJECTIVE: To determine serum prohepcidin levels and their relationship with serum ferritin, C reactive protein (CRP), and albumin in HD patients treated or not with recombinant erythropoietin (EPO) that attended the Health Centre of the Carabobo State in Venezuela. METHODOLOGY: This is a descriptive, correlational, and field investigation with a sample comprised by 71 HD patients of whom 57 were treated with EPO. Serum prohepcidin, ferritin, haemoglobin, hematocrit, CRP, and albumin were determined. Anaemia (haemoglobin < 10 g/dL) and iron deficiency (ferritin < 100 ng/mL) were defined according to the criteria recommended by the K/DOQUI group. Reference values: Albumin 3.5-4.8 g/dL, and for acute inflammatory conditions (CRP > 10 mg/L.). RESULTS: The mean value for prohepcidin was 397.5 ng/mL. A high percentage of anaemia was observed (87.3%) and 22.5% of the patients had low levels of serum ferritin. There were no statistically significant differences for ferritin, albumin, CRP, or prohepcidin, between patients with and without EPO therapy. Only the CRP value was significantly correlated (rho = 0.276; p = 0.020) with prohepcidin. CONCLUSION: HD patients present high levels of prohepcidin, and this may be due to the common ongoing inflammatory process in these patients and not to the iron status measured through serum ferritin levels.

Ankle-brachial pressure index: a simple tool for assessing cardiovascular risk in patients with systemic vasculitis.

OBJECTIVE: Cardiovascular disease may be increased in patients with systemic vasculitides (SV). The Ankle-Brachial Pressure Index (ABPI) is a non-invasive tool for the assessment of cardiovascular risk (CV). Our aim was to determine the prevalence of an abnormal ABPI in patients with SV and healthy controls and to correlate with clinical and serological parameters. METHODS: We studied 54 consecutive vasculitis patients (20 males) attending the vasculitis clinic and 49 healthy subjects. Patients were classified according to the ACR 1990 criteria and the Chapel Hill Consensus definitions. There were 18 patients with Wegener's granulomatosis, eight with Behcet's disease, seven with Churg-Strauss Syndrome, three with Henoch-Schonlein purpura, three with polyarteritis nodosa, three with Takayasu's disease, three with p-ANCA associated vasculitis, three with urticarial vasculitis, two with cutaneous leucocytoclastic angiitis, one with microscopic polyangiitis, one with primary central nervous system angiitis, one giant cell arteritis and one with cutaneous vasculitis secondary to Sjogren's syndrome. Traditional risk factors as well as glucose, lipid profile, CRP, hsCRP, ANCA and aPL were assessed. ABPI was measured according to a consensus statement on the methodology. RESULTS: The ABPI was abnormal in 11/54 (20.4%) of SV patients and 2/49 (4%) of the control group (chi(2) with Yates correction = 4.8, P

Effects of vildagliptin on glucose control in patients with type 2 diabetes inadequately controlled with a sulphonylurea.

AIM: To compare the efficacy and tolerability of vildagliptin vs. placebo in patients with type 2 diabetes mellitus (T2DM) who are inadequately controlled [haemoglobin A(1c) (HbA(1c)) 7.5 to 11%] with prior sulphonylurea (SU) monotherapy. METHODS: This 24-week, multicentre, randomized, double-blind, placebo-controlled study assessed the effects of the dipeptidyl peptidase-4 inhibitor vildagliptin (50 mg given once or twice daily) vs. placebo added to glimepiride (4 mg once daily) in 515 patients with T2DM. Adjusted mean changes from baseline to end-point (AMDelta) in HbA(1c), fasting plasma glucose, fasting lipids and body weight were compared by analysis of covariance. RESULTS: The between-group difference (vildagliptin - placebo) in AMDelta HbA(1c) was -0.6 +/- 0.1% in patients receiving vildagliptin 50 mg daily and -0.7 +/- 0.1% in those receiving 100 mg daily (p < 0.001 vs. placebo for both). Greater efficacy was seen in patients > or =65 years of age (-0.7 +/- 0.1% and -0.8 +/- 0.2% for 50 and 100 mg daily respectively) and in patients with baseline HbA(1c) > 9% (Delta = -1.0 +/- 0.2% and -0.9 +/- 0.2% for 50 and 100 mg daily respectively). Relative to placebo, patients receiving vildagliptin also had improvements in beta-cell function and postprandial glucose, with small changes in fasting lipids and body weight. The incidences of adverse events (AEs) (67.1, 66.3 and 64.2%) and serious AEs (2.9, 2.4 and 5.1%) were similar in patients receiving 50 mg vildagliptin, 100 mg vildagliptin or placebo respectively. The incidence of hypoglycaemic events was low but slightly higher in the group receiving vildagliptin 100 mg (3.6%) than in the group receiving vildagliptin 50 mg (1.2%) or placebo (0.6%). CONCLUSIONS: In patients with T2DM inadequately controlled with prior SU monotherapy, addition of vildagliptin (50 or 100 mg daily) to glimepiride (4 mg once daily) improves glycaemic control and is well tolerated. Addition of vildagliptin 50 mg daily to SU monotherapy may be a particularly attractive therapy in elderly patients.

Nateglinide, alone or in combination with metformin, is effective and well tolerated in treatment-naïve elderly patients with type 2 diabetes.

AIM: The aim of this work was to assess the efficacy and tolerability of nateglinide alone or in combination with metformin in elderly patients with type 2 diabetes (T2DM). METHODS: Study 1 was a 12-week, multicentre, randomized, double blind and placebo-controlled study of nateglinide monotherapy (120 mg, before meals) in 66 drug-naïve patients with T2DM aged >or=65 years. Study 2 was a 104-week, multicentre, randomized, double blind and active-controlled study of nateglinide (120 mg, before meals) or glyburide (up to 5 mg bid) in combination with metformin (up to 1000 mg bid) in 69 treatment-naïve patients with T2DM aged >or=65 years. HbA(1c), fasting and postprandial glucose levels, and safety assessments were made. RESULTS: In Study 1, nateglinide significantly reduced HbA(1c) from baseline (7.6 +/- 0.1% to 6.9 +/- 0.1%; Delta = -0.7 +/- 0.1%, p < 0.001) and compared with placebo (between-group difference = -0.5%, p = 0.004 vs. nateglinide). No hypoglycaemia was reported. In Study 2, combination therapy with nateglinide/metformin significantly reduced HbA(1c) from baseline (7.8 +/- 0.2% to 6.6 +/- 0.1%; Delta = -1.2 +/- 0.2%, p < 0.001), as did glyburide/metformin (7.7 +/- 0.1% to 6.5 +/- 0.1%; Delta = -1.2 +/- 0.1%, p < 0.001). There was no difference between treatments (p = 0.310). One nateglinide/metformin-treated patient experienced a mild hypoglycaemic episode compared with eight episodes in eight patients on glyburide/metformin; one severe episode led to discontinuation. Target HbA(1c) (<7.0%) was achieved by 60% of patients receiving nateglinide (Study 1) and 70% of nateglinide/metformin-treated patients (Study 2). CONCLUSION: Initial drug treatment with nateglinide, alone or in combination with metformin, is well tolerated and produces clinically meaningful improvements in glycaemic control in elderly patients with T2DM.

Addition of vildagliptin to insulin improves glycaemic control in type 2 diabetes.

AIMS/HYPOTHESIS: Type 2 diabetes is difficult to manage in patients with a long history of disease requiring insulin therapy. Moreover, addition of most currently available oral antidiabetic agents increases the risk of hypoglycaemia. Vildagliptin is a dipeptidyl peptidase-IV inhibitor, which improves glycaemic control by increasing pancreatic beta cell responsiveness to glucose and suppressing inappropriate glucagon secretion. This study assessed the efficacy and tolerability of vildagliptin added to insulin therapy in patients with type 2 diabetes. MATERIALS AND METHODS: This was a multicentre, 24-week, double-blind, randomised, placebo-controlled, parallel-group study in patients with type 2 diabetes that was inadequately controlled (HbA(1c) = 7.5-11%) by insulin. Patients received vildagliptin (n = 144; 50 mg twice daily) or placebo (n = 152) while continuing insulin therapy. RESULTS: Baseline HbA(1c) averaged 8.4 +/- 0.1% in both groups. The adjusted mean change from baseline to endpoint (AMDelta) in HbA(1c) was -0.5 +/- 0.1% and -0.2 +/- 0.1% in patients receiving vildagliptin or placebo, respectively, with a significant between-treatment difference (p = 0.01). In patients aged >/=65 years, the AMDelta HbA(1c) was -0.7 +/- 0.1% in the vildagliptin group vs -0.1 +/- 0.1% in the placebo group (p < 0.001). The incidence of adverse events was similar in the vildagliptin (81.3%) and placebo (82.9%) groups. However, hypoglycaemic events were less common (p < 0.001) and less severe (p < 0.05) in patients receiving vildagliptin than in those receiving placebo. CONCLUSIONS/INTERPRETATION: Vildagliptin decreases HbA(1c) in patients whose type 2 diabetes is poorly controlled with high doses of insulin. Addition of vildagliptin to insulin therapy is also associated with reduced confirmed and severe hypoglycaemia. ClinicalTrials.gov ID no.: NCT 00099931.

Homocisteína, ácido fólico y vitamina B12 en adultos mayores venezolanos / Serum homocysteine, folate and vitamin B12 in venezuelan elderly

Los cambios anatomo-fisiológicos propios del envejecimiento hacen de los adultos mayores un grupo vulnerable a los estados de malnutrición y deficiencias específicas de nutrientes como la vitamina B12 y el folato. El objetivo de este estudio fue establecer la relación existente entre la vitamina B12, folato, homocisteína y el consumo y adecuación de estos nutrientes. Se evaluaron 55 adultos mayores de 60 años de edad, de ambos sexos, no institucionalizados, a quienes se les determinó homocisteína sérica por inmunoensayo de polarización de fluorescencia, vitamina B12 y folato sérico por radioensayo (RIA); consumo de nutrientes según recordatorio de 24 h y frecuencia de consumo de alimentos y estado nutricional antropométrico según Indice de Masa Corporal (IMC). Se encontraron niveles séricos de vitamina B12 y folato dentro de los valores de referencia (423,3± 227,6 pmol/l y 6,4 ± 4,5 mg/ml); sin embargo, 17,5% se encontraban deficitarios de B12 y 12% de ácido fólico, la homocisteína sérica estuvo por encima de los valores de referencia (15,8±4,4 mmol/l). Del grupo de estudio, 47,5% presentaban hiperhomocisteinemia (>15mmol/L), siendo significativamente más alta para el sexo masculino (p: 0,01). El consumo de nutrientes fue inadecuado por déficit. Según IMC, 11,8% de los adultos mayores se encontraban en déficit nutricional, 29,4% con sobrepeso y 20,6% en obesidad. Se observó una correlación inversa y negativa entre homcisteína y folato sérico. Todo esto sugiere la presencia de una deficiencia bioquímica de B12 y folato, que se traduce en la homocisteína elevada, lo que constituye un factor de riesgo cardiovascular en este grupo de adultos mayores.

Serum homocysteine, folate and vitamin B12 in Venezuelan elderly. The anatomical and physiological changes of aging make elderly people a vulnerable group to malnutrition and specific deficiencies of nutrients such as vitamin B12 and folate. This study was aimed to establish relationships among serum vitamin B12, folate, homocysteine concentrations and dietary intake and adequacy. Fifty five male and female elderly (60 and more years), free-living, were assessed. Measurements were: serum vitamin B12 and folate by radioimmunoanalysis (RIA), homocysteine by polarized fluorescence immunoassay, nutrient intake by three 24 hours recalls and food frequency questionnaire. Nutritional status was determined by Body Mass Index (BMI). Serum vitamin B12 and folate were at normal range (423,3±227,6 pmol/l and 6,4 ± 4,5 mg/ml), but 17,5% of elderly had B12 deficiency and 12% had folate deficiency. Serum homocysteine was higher than reference values (15,8±4,4 mmol/l), but 47,5% showed concentrations above 15mmol/L, male population showed higher mean value (p: 0,01). Nutrient intake was inadequate by deficiency. BMI indicated 11,8% of undernutrition, 29,4% of overweight and 20,6% of obesity A negative and inverse correlation between homocysteine and serum folate was found. Results suggest a biochemical deficiency of B12 and folate that is expressed as elevated homocysteine levels. These finding represent a high cardiovascular risk factor for this elderly group.

Vildagliptin in combination with pioglitazone improves glycaemic control in patients with type 2 diabetes failing thiazolidinedione monotherapy: a randomized, placebo-controlled study.

AIM: The purpose of this study was to assess the efficacy and tolerability of the dipeptidyl peptidase-4 inhibitor vildagliptin in combination with the thiazolidinedione (TZD) pioglitazone in patients with type 2 diabetes (T2DM). METHODS: This was a 24-week, multicentre, double-blind, randomized, parallel-group study comparing the effects of vildagliptin (50 or 100 mg daily) with placebo as an add-on therapy to pioglitazone (45 mg daily) in 463 patients with T2DM inadequately controlled by prior TZD monotherapy. Between-treatment comparisons of efficacy parameters were made by analysis of covariance model. RESULTS: The adjusted mean change (AM Delta) in haemoglobin A(1c) from baseline to endpoint was -0.8 +/- 0.1% (p = 0.001 vs. placebo) and -1.0 +/- 0.1% (p < 0.001 vs. placebo), respectively, in patients receiving vildagliptin 50 or 100 mg daily. Relative to baseline, vildagliptin added to pioglitazone also reduced fasting plasma glucose (FPG) (AM Delta FPG =-0.8 +/- 0.2 mmol/l and -1.1 +/- 0.2 mmol/l; not significant (NS) vs. placebo) and postprandial glucose (PPG) [AM Delta PPG =-1.9 +/- 0.6 mmol/l and -2.6 +/- 0.6 mmol/l (p = 0.008 vs. placebo)] for 50 and 100 mg daily respectively. Relative to placebo, both doses of vildagliptin significantly increased the insulin secretory rate/glucose by more than threefold. The overall incidence of adverse events (AEs) was 55.5, 50.0 and 48.7% in patients receiving vildagliptin 50 mg, 100 mg daily or placebo respectively. Serious AEs were experienced by 6.8, 1.3 and 5.7% of patients receiving vildagliptin 50 mg, 100 mg daily or placebo respectively. Mild hypoglycaemia was reported by 0, 0.6 and 1.9% of patients, respectively, receiving vildagliptin 50 mg, 100 mg daily or placebo. CONCLUSION: Vildagliptin is effective and well tolerated when added to a maximum dose of pioglitazone, without increasing the risk of hypoglycaemia.

Efficacy and tolerability of initial combination therapy with vildagliptin and pioglitazone compared with component monotherapy in patients with type 2 diabetes.

AIM: The aim of this study was to compare efficacy and tolerability of initial combination therapy with vildagliptin/pioglitazone to component monotherapy. METHODS: This 24-week, multicentre, randomized, double-blind, active-controlled study assessed the effects of the dipeptidyl peptidase-4 inhibitor vildagliptin (100 mg q.d.), pioglitazone (30 mg q.d.) and vildagliptin combined with pioglitazone (100/30 mg q.d. or 50/15 mg q.d.) in 607 drug-naive patients with type 2 diabetes (T2DM). The primary outcome measure was change from baseline in HbA(1c) in patients receiving initial combination therapy compared with pioglitazone monotherapy. RESULTS: After 24-week treatment, adjusted mean changes in HbA(1c) from baseline (approximately 8.7%) in patients receiving pioglitazone monotherapy, 50/15 mg combination, 100/30 mg combination and vildagliptin monotherapy were -1.4 +/- 0.1%, -1.7 +/- 0.1%, -1.9 +/- 0.1% and -1.1 +/- 0.1% respectively. Both low-dose and high-dose combinations were significantly more efficacious than pioglitazone alone (p = 0.039 and p < 0.001 respectively). Adjusted mean changes in fasting plasma glucose were -1.9 +/- 0.2, -2.4 +/- 0.2, -2.8 +/- 0.2 and -1.3 +/- 0.2 mmol/l respectively, and both combination groups were significantly more effective than pioglitazone monotherapy (p = 0.022 and p < 0.001 respectively). The overall incidence of adverse events ranged from 45.8% in the low-dose combination to 51.6% in the pioglitazone monotherapy group. The incidence of peripheral oedema was highest in patients receiving pioglitazone monotherapy (9.3%) and lowest in those receiving low-dose combination (3.5%). One mild hypoglycaemic event was reported by one patient receiving high-dose combination and one patient receiving vildagliptin monotherapy. CONCLUSIONS: First-line treatment with vildagliptin/pioglitazone combination in patients with T2DM provides better glycaemic control than either monotherapy component yet has minimal risk of hypoglycaemia and a tolerability profile comparable with component monotherapy.

Infección por Helicobacter pylori (13C-UBT) y factores nutricionales y socioeconómicos asociados en escolares de estratos bajos de la ciudad de Valencia. Venezuela / Helicobacter pylori infection (13C-UBT) and its relationship with nutritional and socioeconomic factors in low income school children from Valencia venezuela

La infección con Helicobacter pylori (Hp) está altamente diseminada a nivel mundial y es considerada una de las causas principales de gastritis crónica, úlceras pépticas y duodenales y cáncer gástrico. Trabajos recientes han mostrado que esta puede tener implicaciones nutricionales, principalmente sobre el estado de hierro y otros micronutrientes. El objetivo fue evaluar la prevalencia de infección con Hp y el patrón de infección según edad, sexo, estado nutricional y condiciones socioeconómicas, en niños que asistían a Unidad Educativa "Valentín Espinal" de Valencia. Se evaluaron 170 niños entre 3 y 14 años de edad, de ambos géneros. Se determinó: Infección por Hp (test de aliento con urea-C13), edad, estado nutricional según IMC y Talla-Edad, hemoglobina (cianometahemoglobina), ferritina sérica (ELISA), estrato socioeconómico (Graffar-Méndez-Castellano), condición de vivienda, número de personas y familias que viven en el hogar y calidad de los servicios. El 78,8 por ciento de los niños estaban infectados con Hp, no encontrándose correlación significativa con el género pero si con la edad; 25,9 por ciento presentaron déficit nutricional y 46,5 por ciento talla baja, El 98,1 por ciento de las familias se encontraban en situación de pobreza (estratos IV y V) y 98 por ciento de las viviendas presentaban deficiencias sanitarias; En promedio vivían 6,0±2,4 personas en el hogar (rango: 2 a 15) y 3,2 personas compartían un mismo dormitorio. Se encontró que la probabilidad de infección era mayor en aquellos niños que presentaban déficit de talla y que el estrato socioeconómico, el nivel de instrucción materno, las precarias condiciones de alojamiento y el hacinamiento se asociaban significativamente a la infección. La deprivación socioeconómica en la niñez esta asociada con una alta colonización del Hp, la edad, el hacinamiento y un bajo nivel de instrucción de la madre pueden aumentar el riesgo a esta infección

[Helicobacter pylori infection (13C-UBT), and its relationship with nutritional and socioeconomic factors in low income school children from Valencia, Venezuela]. / Infección por helicobacter pylori (13C-UBT) y factores nutricionales y socioeconómicos asociados en escolares de estratos bajos de la ciudad de Valencia, Venezuela.

Helicobacter pylori infection (Hp) is widely spread around the world, and it is considered one of the main causes of chronic gastritis, peptic and duodenal ulcers, and gastric cancer. Recent research has shown that it can be associated with nutritional disorders, mainly with iron and other micronutrient deficiencies. The objective of this study was to assess the prevalence of Hp infection, and infection pattern according to age, sex, nutritional status, and socioeconomic conditions in children who attended the Unidad Educativa "Valentin Espinal" in the city of Valencia. 170 children, between 3 and 14 years of age were studied to assess Hpylori infection (13C-urea breath test), age, nutritional status according to BMI and Height for age, hemoglobin (cianometahemoglobin), serum ferritin (ELISA), socioeconomic status (Graffar-Méndez-Castellano), housing conditions, number of families and of people cohabitating in the same household, and quality of services. 78.8% of the children were infected with Hp, witch was significantly correlated with age but not gender. 25.9% of the sample had undernutrition, and 46.5% were stunted. 98.1% of the families lived in poverty, and 98% of the households showed sanitary deficiencies. A mean of 6.0 +/- 2.4 persons lived in each household (range: 2-15), and an average of 3.2 person shared bedrooms. The odds of being infected were higher in those children who were stunted. Also, socioeconomic status, mother's education level, and poor hosing conditions were significantly associated to being infected. Hpylori is highly prevalent among socially and economically deprived children, and age, overcrowding, and a low education level of the mother increases the risk of being infected.

Prevalence of an abnormal ankle-brachial index in patients with primary antiphospholipid syndrome: preliminary data.

OBJECTIVES: To evaluate the prevalence of abnormal ankle-brachial indexes (ABIs), their relationship with other cardiovascular risk factors and/or the presence of antiphospholipid antibodies (aPL), and the clinical use of the ABI in patients with primary antiphospholipid syndrome (primary APS). METHODS: An 8 MHz Doppler probe was used in the arms and legs to assess the ABI in 43 patients with primary APS (mean (SD) age 40.2 (7.9) years) and 49 healthy subjects (aged 41.0 (11.7)) matched for age and sex. Data on traditional cardiovascular risk factors, such as hypertension, hypercholesterolaemia, presence of diabetes mellitus, nephrotic syndrome or renal failure, smoking, and other variables, were collected at that time for all subjects. A ratio of the highest blood pressure from the posterior tibial or pedal arteries of each leg to the highest blood pressure from the brachial arteries <1.00 was considered abnormal. RESULTS: Abnormal ABIs were found in 8/43 (19%) patients with primary APS and 2/49 (4%) controls (p = 0.026). No correlation between abnormal ABI and traditional cardiovascular risk factors nor with the presence of aPL was found. CONCLUSION: Abnormal ABIs are more common in primary APS than in healthy controls, possibly indicating a subclinical atherosclerotic process in these patients.

Hypoglycemic potential of nateglinide versus glyburide in patients with type 2 diabetes mellitus.

Antidiabetic agents that augment insulin secretion can cause hypoglycemia. With the current trend toward early and aggressive treatment of patients with type 2 diabetes, the hypoglycemic potential of insulinotropic agents is of concern. This study aimed to compare the propensity of the "glinide," nateglinide, and the sulfonylurea (SU), glyburide, to elicit hypoglycemia in type 2 diabetic patients with moderately elevated fasting plasma glucose (FPG). Hyperglycemic clamps (target plasma glucose = 11.1 mmol/L) were initiated, and 30 minutes later patients received a single oral dose of nateglinide (120 mg, n = 15) or glyburide (10 mg, n = 12) in a double-blind fashion. At the end of the 2-hour clamp when the glucose infusion was terminated, plasma glucose and insulin levels were measured for 4 additional hours. The minimum plasma glucose level achieved after terminating the glucose infusion (glucose nadir) was used as an index of hypoglycemic potential. The mean (+/-SEM) glucose nadir was significantly lower in patients given glyburide (3.3 +/- 0.2 mmol/L) versus nateglinide (4.4 +/- 0.3 mmol/L, P = .025). Confirmed hypoglycemia (plasma glucose < or = 2.8 mmol/L) occurred in 2 of 12 patients given glyburide and in none of those given nateglinide. Plasma insulin levels were significantly higher from 100 to 240 minutes after clamp termination in patients given glyburide versus nateglinide. Nateglinide has less hypoglycemic potential than glyburide, suggesting that nateglinide may be a more appropriate insulinotropic agent for patients with moderate fasting hyperglycemia, such as elderly patients and those with comorbid cardiac ischemia.

Estado de la nutrición de folato, vitamina B12 y hierro en adolescentes embarazadas / Nutritional status of folate, vitamin B12 and iron in pregnant adolescents

Pregnancy in adolescence increases nutritional risk, due to higher demand of nutrients for maternal and fetal growth. This study was aimed to evaluate folate, vitamin B12 and iron status of pregnant adolescents at first trimester of pregnancy. A cross sectional, descriptive study was performed in 122 pregnant adolescents from Valencia, Carabobo state, 1997. Serum and erythrocyte folate and serum vitamin B12 was determined by radioassay; serum ferritin by enzimoimmunoassay; hemoglobin were performed by semi-automated method. Statistical analysis included standard deviation and frequencies. For serum folate 1.7 per cent was found in negative balance and 19.0 per cent at marginal status. For erythrocyte folate, 5.8 per cent was deficient and 1.7 per cent marginal. For serum vitamin B12, 8.3 per cent was deficient and 13.2 per cent marginal. Iron deficiency was found in 19.0 per cent of the adolescents. Prevalence of anemia was of 13.1 per cent, being iron deficiency the main cause. There was high nutritional risk regarding iron status, although iron intakes exceeded the recommendations, but only a small proportion was bioavailable. Prevalence of anemia was lower than reported by other studies and iron deficiency was higher than folic acid and vitamin B12 deficiencies. Pregnant adolescents are at a high biological and nutritional risk.

Abdominal wall metastasis from ovarian cancer after laparotomy. A case report.

A 27-year-old woman underwent surgery for an abdominal wall mass later confirmed to be a relapse of Stage I ovarian mucinous adenocarcinoma. The authors stress that caution should be observed during laparotomy to remove a malignant neoplasm in order to avoid parietal dissemination.

Iron bioavailability in humans from breakfasts enriched with iron bis-glycine chelate, phytates and polyphenols.

This study was conducted to determine the bioavailability of iron amino acid chelate (ferrochel) added to fortify breads prepared from either precooked corn flour or white wheat flour + cheese and margarine compared with the same basal breakfast enriched with either ferrous sulfate or iron-EDTA. The inhibitory effect of phytate and polyphenols on iron absorption from ferrochel was also tested. A total of 74 subjects were studied in five experiments. Iron absorption from ferrochel was about twice the absorption from ferrous sulfate (P: < 0.05). When ferrous sulfate and ferrochel were administered together or in different meals, absorption from ferrochel was about twice the absorption from ferrous sulfate (P: < 0.05). Polyphenols present in coffee and tea inhibited iron absorption in a dose-dependent manner. American-type coffee did not modify iron absorption significantly, whereas both espresso-type coffee and tea reduced iron absorption from ferrochel by 50% (P: < 0. 05). Ferrochel partially prevented the inhibitory effect of phytates. Because of its high solubility in aqueous solutions even at pH 6, its low interactions with food and high absorption, ferrochel is a suitable compound for food fortification.

New property of vitamin A and beta-carotene on human iron absorption: effect on phytate and polyphenols as inhibitors of iron absorption.

One hundred and seventy four human subjects were studied to find out the interaction of vitamin A or beta-carotene with the inhibitors of iron absorption, from a basal breakfast containing bread from either 100 g of precooked corn flour or 100 g of white wheat flour, 50 g of cheese and 10 g of margarine. Bread was labeled with either 55Fe or 59Fe. This bread was made from commercially flours fortified with iron as ferrous fumarate and vitamins. It was noticed that the percentage of iron absorption from the breakfast prepared with precooked corn flour given alone and with different concentrations of coffee was practically the same, while the iron absorption from the breakfast prepared from wheat flour decreased from 6% when the breakfast was given alone, to less than 2% when it was given with different concentrations of coffee. The only ingredient present in precooked corn flour and not in wheat flour was vitamin A. This difference encouraged the authors to perform further experiments using precooked corn and wheat flours fortified only with ferrous fumarate. These studies demonstrated that vitamin A inhibits the effect of the polyphenol and partially inhibits the effect phytate on iron absorption. HPLC and spectrophotometric studies demonstrated an interaction between vitamin A and iron. Other experiments, which included 100 volunteers, were performed to test the effect of vitamin A and beta-carotene on iron absorption from corn, wheat and rice. The presence of vitamin A increased iron absorption up to 3 times for rice, 2.4 times for wheat and 1.8 times for corn. beta-carotene increased absorption almost 3 times for the three cereals tested, showing that both compounds were capable of preventing the inhibitory effect of phytates on iron absorption. This information suggest that vitamin A and beta-carotene form a complex with iron keeping it soluble in the intestinal lumen and preventing the inhibitory effect of phytates and polyphenols on iron absorption.

Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans.

After the rapid decrease in the prevalence of iron deficiency and iron-deficiency anemia in the Venezuelan population when a national program for fortification of flours with iron and vitamins was instituted, we studied micronutrient interactions in Venezuelan diets. One hundred human adults were fed three cereal-based diets, labelled with either 59Fe or 55Fe in six studies. Each diet contained different concentrations of vitamin A (from 0.37 to 2.78 micromol/100 g cereal) or beta-carotene (from 0.58 to 2.06 micromol/100 g cereal). The presence of vitamin A increased iron absorption up to twofold for rice, 0.8-fold for wheat and 1.4-fold for corn. beta-carotene increased absorption more than threefold for rice and 1.8-fold for wheat and corn, suggesting that both compounds prevented the inhibitory effect of phytates on iron absorption. Increasing the doses of vitamin A or beta-carotene did not further significantly increase iron absorption. We measured the iron remaining in solution performing in vitro studies in which the pH of solutions was adjusted from 2 to 6 in the presence of vitamin A or beta-carotene. All of the iron from ferrous fumarate was soluble after changing the pH of the solution containing 3.4 micromol of beta-carotene to 6.0. Vitamin A was less effective. However, 78 +/- 18% of iron was soluble in the presence of 3.3 micromol of vitamin A, whereas with no vitamin addition, only 26 +/- 13% of iron was soluble (<0.05). Vitamin A and beta-carotene may form a complex with iron, keeping it soluble in the intestinal lumen and preventing the inhibitory effect of phytates and polyphenols on iron absorption.

Fever without apparent source on clinical examination, lower respiratory infections in children, other infectious diseases, and acute gastroenteritis and diarrhea of infancy and early childhood.

This section focuses on issues in infectious disease that are commonly encountered in pediatric office practice. Paul McCarthy discusses recent literature regarding the evaluation and management of acute fevers without apparent source on clinical examination in infants and children and the evaluation of children with prolonged fevers of unknown origin. Jean Klig reviews recent literature about lower respiratory tract infection in children. Jeffrey Kahn and Eugene Shapiro discuss literature concerning several infectious diseases commonly seen in office settings and concerning which recent developments are of interest. Michael Baron reviews recent literature about gastroenteritis and diarrhea of infancy and early childhood.