Measurement of liver iron overload: noninvasive calibration of MRI-R2* by magnetic iron detector susceptometer.

An accurate assessment of body iron accumulation is essential for the diagnosis and therapy of iron overload in diseases such as thalassemia or hemochromatosis. Magnetic iron detector susceptometry and MRI are noninvasive techniques capable of detecting iron overload in the liver. Although the transverse relaxation rate measured by MRI can be correlated with the presence of iron, a calibration step is needed to obtain the liver iron concentration. Magnetic iron detector provides an evaluation of the iron overload in the whole liver. In this article, we describe a retrospective observational study comparing magnetic iron detector and MRI examinations performed on the same group of 97 patients with transfusional or congenital iron overload. A biopsy-free linear calibration to convert the average transverse relaxation rate in iron overload (R(2) = 0.72), or in liver iron concentration evaluated in wet tissue (R(2) = 0.68), is presented. This article also compares liver iron concentrations calculated in dry tissue using MRI and the existing biopsy calibration with liver iron concentrations evaluated in wet tissue by magnetic iron detector to obtain an estimate of the wet-to-dry conversion factor of 6.7 ± 0.8 (95% confidence level).

Total iron-overload measurement in the human liver region by the magnetic iron detector.

An accurate assessment of body iron accumulation is essential for the diagnosis and therapy of iron overload in diseases, such as hemochromatosis, thalassemia and other forms of severe anemias. The magnetic iron detector (MID) is a room-temperature susceptometer, which measures the total iron overload in the liver. Since February 2005, about 600 patients have been assessed using this device. The iron overload is obtained by calculating the difference between the measured magnetization signal of the patient and the patient's background signal. The latter is the magnetization signal that the patient would generate with normal iron content. This study presents the method for calculating the background signal of healthy volunteers and the application of the same method to patients with iron burden in order to evaluate their overload. The present MID sensitivity is 0.8 g and the reproducibility of the iron overload measurement of the same patients is lower than 0.5 g. The MID does not require calibration with liver biopsies. We correlated the MID measurements with the results of 26 biopsies (R = 0.62), 64 superconducting quantum interference device susceptometer measurements (R = 0.79), 666 serum ferritin concentration measurements (R = 0.72), and 41 MRI- R2* measurements (R = 0.71).

Pathogenicity and Host-Parasite Relationships of Meloidogyne arenaria in Sweet Basil.

Stunted growth of sweet basil (cv. Genovese) associated with large patches and severe soil infestations by the root-knot nematode Meloidogyne arenaria race 2 were observed in open fields at the end of the crop-growing season in Albenga, province of Savona, Northern Italy by early September 2007. Observed morphological traits of nematode life stages and results of analysis of isozyme electrophoretic patterns and differential host tests were used for nematode species and race identification. Nematode-induced mature galls (either in naturally infected plants or in artificially inoculated root tissues) were spherical or ellipsoidal and confluent along the root axis, containing usually several females, males, and egg-masses with eggs. Feeding sites were characterized by the development of giant cells that contained several hypertrophied nuclei and nucleoli. Giant cell cytoplasm was aggregated along the thickened cell walls. Vascular elements within galls appeared disorganized and disrupted. Due to the heavy damage observed, the relationships between the initial population density and growth of basil plants was also tested in a greenhouse experiment in which inoculum levels varied from 0 to 512 eggs and juveniles/cm3 of soil. Height and top fresh weight data of the inoculated and control plants was fitted to Seinhorst's model. Tolerance limits with respect to plant height and fresh top weight of basil cv. Genovese plants to M. arenaria race 2 were estimated as 0.15 eggs and juveniles/cm3 of soil. The minimum relative values (m) for plant height and top fresh weight were 0.39 and 0.19 at initial nematode population density (Pi) ≥16 eggs and juveniles/cm3 of soil, respectively. The maximum nematode reproduction rate (Pf/Pi) was 448.7 times at an initial population density of 4 eggs and second-stage juveniles/cm3 of soil.

Molecular defects in ferrochelatase in patients with protoporphyria requiring liver transplantation.

Protoporphyria is a genetic disorder in which a deficiency of mitochondrial ferrochelatase activity causes accumulation of protoporphyrin that produces severe liver damage in some patients. In this study, mutations of the ferrochelatase gene were examined in eight unrelated patients who had liver transplantation. RNA was prepared from liver and/ or lymphoblasts, and specific reverse transcriptase-nested polymerase chain reactions amplified and sequenced ferrochelatase cDNAs. Products shorter than normal resulted from an exon 3 deletion in three patients, exon 10 deletion in two, exon 2 deletion in one, and deletion of five nucleotides in exon 5 in one. Sequence of normal-size products revealed no other mutations. Western blot showed a reduced quantity of normal-size ferrochelatase protein in protoporphyria liver compared with normal liver (19-51%, mean 32% of normal). Levels of the mitochondrial protein F1-ATPase beta-subunit were not decreased to a similar degree. Liver ferrochelatase activity was reduced more than could be explained by the decrease in ferrochelatase protein (4-20%, mean 9% of normal). These results establish genetic heterogeneity in the most severe phenotype of protoporphyria. However, the gene mutations found share the property of causing a major structural alteration in the ferrochelatase protein.

Blood pressure and heart rate responses during 24-hour ambulatory monitoring and exercise in men with diabetes mellitus.

The heart rate (HR) variation of 25 normotensive and asymptomatic men, mean age 58 +/- 7 years, with diabetes mellitus (group I) was studied during deep respiration. Thirteen subjects (52%) had a variation of 10 beats/min or less, consistent with an autonomic neuropathy (AN) (group IA); 12 had variation in HR of more than 10 beats/min and were considered to have no neuropathy (group IB). The 24-hour ambulatory HR and systolic blood pressure (BP) values of group I were compared with those of 13 healthy men, mean age 48 +/- 8 years (group II). The mean of 5 maximal HR measurements during the 24-hour period was higher for group IA (106 +/- 11 beats/min) than for group IB (100 +/- 13 beats/min) or for group II (92 +/- 9 beats/min) (p less than 0.01). The mean of 5 maximal BP measurements was greater for group I (149 +/- 28 mm Hg) than for group II (128 +/- 13 mm Hg) (p less than 0.01), but no difference was observed between groups IA and IB. Maximal treadmill exercise was performed with 22 of the patients (11 with and 11 without AN), and no difference in HR was observed between the 2 groups during all stages of exercise or at maximal exertion. The increase in systolic BP and duration of exercise in these 2 groups were also similar. Seventeen of 25 diabetic men had peripheral neuropathy (PN). Of 13 patients with AN, 10 had PN; of 12 without AN, 7 had PN and 5 did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin responses to glucose in non-insulin-dependent diabetic subjects with and without the chlorpropamide-alcohol flush: effect of salicylate and naloxone.

We examined the role of endogenous opiates and/or prostaglandins on the abnormal insulin secretion characteristic of some non-insulin-dependent diabetic subjects. A group of chlorpropamide-alcohol flush positive (CPAF+) and a group of flush negative (CPAF-) non-insulin-dependent subjects were compared as to their pancreatic beta-cell responses to intravenous glucose tolerance tests before and after sodium salicylate infusion, and before and after naloxone infusion. There was no difference in mean insulin secretion (either first or second phase) between CPAF+ versus CPAF- groups. Both groups increased their insulin secretion with salicylate infusion, and both had a small decrease with naloxone infusion. There was no correlation between chlorpropamide-alcohol flushing and beta-cell response to glucose.