bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral supplementation with whey proteins increases plasma glutathione levels of HIV‐infected patients
Authors: Micke P. , Beeh K. M. , Schlaak J. F. , Buhl R.
Published: March 2003

HIV infection is characterized by an enhanced oxidant burden and a systemic deficiency of the tripeptide glutathione (GSH), a major antioxidant. The semi‐essential amino acid cysteine is the main source of the free sulfhydryl group of GSH and limits its synthesis. Therefore, different strategies to supplement cysteine supply have been suggested to increase glutathione levels in HIV‐infected individuals. The aim of this study was to evaluate the effect of oral supplementation with two different cysteine‐rich whey protein formulas on plasma GSH levels and parameters of oxidative stress and immune status in HIV‐infected patients.

In a prospective double blind clinical trial, 30 patients (25 male, 5 female; mean age (± SD) 42 ± 9·8 years) with stable HIV infection (221 ± 102 CD4 + lymphocytes L−1) were randomized to a supplemental diet with a daily dose of 45 g whey proteins of either Protectamin (Fresenius Kabi, Bad Hamburg, Germany) or Immunocal (Immunotec, Vandreuil, Canada) for two weeks. Plasma concentrations of total, reduced and oxidized GSH, superoxide anion (O2–) release by blood mononuclear cells, plasma levels of TNF‐α and interleukins 2 and 12 were quantified with standard methods at baseline and after therapy.

Pre‐therapy, plasma GSH levels (Protectamin: 1·92 ± 0·6 μM; Immunocal: 1·98 ± 0·9 μM) were less than normal (2·64 ± 0·7 μM, P = 0·03). Following two weeks of oral supplementation with whey proteins, plasma GSH levels increased in the Protectamin group by 44 ± 56% (2·79 ± 1·2 μM, P = 0·004) while the difference in the Immunocal group did not reach significance (+ 24·5 ± 59%, 2·51 ± 1·48 μM, P = 0·43). Spontaneous O2– release by blood mononuclear cells was stable (20·1 ± 14·2 vs. 22·6 ± 16·1 nmol h−1 10−6 cells, P = 0·52) whereas PMA‐induced O2– release decreased in the Protectamin group (53·7 ± 19 vs. 39·8 ± 18 nmol h−1 10−6 cells, P = 0·04). Plasma concentrations of TNF‐α and interleukins 2 and 12 (P > 0·08, all comparisons) as well as routine clinical parameters remained unchanged. Therapy was well tolerated.

In glutathione‐deficient patients with advanced HIV‐infection, short‐term oral supplementation with whey proteins increases plasma glutathione levels. A long‐term clinical trial is clearly warranted to see if this ‘biochemical efficacy’ of whey proteins translates into a more favourable course of the disease.
Somatostatin receptor subtype 2 and 5 in human GH‐secreting pituitary adenomas: analysis of gene sequence and mRNA expression
Authors: Corbetta S. , Ballaré E. , Mantovani G. , Lania A. , Losa M. , Di Blasio A. M. , Spada A.
Published: March 2003

The role of somatostatin receptor subtypes 2 and 5 (SSTR2 and SSTR5) in determining the secretory and proliferative phenotype as well as the sensitivity to somatostatin analogue treatment is not clearly established.

We quantified the expression of SSTR2 and SSTR5 mRNA using a semiquantitative reverse transcription‐polymerase chain reaction (RT‐PCR) in 19 human growth hormone (GH) ‐secreting adenomas. Tumour characteristics and in vivo sensitivity to somatostatin analogues were assessed; tumours were screened for Gsα gene mutations. PCR products of SSTR2 and SSTR5 DNA from tumours resistant to somatostatin analogues were directly sequenced.

All tumours expressed both SSTR2 and SSTR5 mRNA at variable levels. No significant correlation between SSTR2 and SSTR5 expression and the presence of Gsα mutation, GH levels, or tumour size and invasiveness was observed. A negative correlation between SSTR2 and SSTR5 mRNA levels was observed (r = 0·5; P < 0·05). No significant correlation between the levels of SSTR2 and SSTR5 expression and the in vivo responsiveness to somatostatin analogues was observed, although a tendency to a low SSTR2 expression in resistant tumours was found. No mutations in the coding or bordering regions of either SSTR2 or SSTR5 adenomatous DNA from patients totally or partially resistant to somatostatin analogues were found.

The study shows that the different expression of SSTR2 and SSTR5 in GH‐secreting adenomas is not significantly correlated with the secretory and proliferative phenotype, although the large, hypersecretory tumours and those with a poor sensitivity to somatostatin analogues seem to express low levels of SSTR2 mRNA. Moreover, both SSTR2 and SSTR5 DNA from tumours resistant to somatostatin analogues were found to possess intact coding sequences.
Levels of vasodilators (SP, CGRP) and vasoconstrictor (NPY) peptides in early human burns
Authors: Onuoha G. N. , Alpar E. K.
Published: March 2003

An intact nociceptor system of primary afferent sensory nerves is important for the initiation of the inflammatory process and successful tissue repair. Dysfunction of this system could be a contributing factor for delayed wound healing in humans. We examined the levels of vasodilators [substance P (SP), calcitonin gene‐related peptide (CGRP)] and a vasoconstrictor peptide [neuropeptide Y (NPY)] in the peripheral blood samples of patients with burns covering from 20 to 75% of body surface area.

Thirteen patient samples were obtained immediately on admission (OA), which was within 12 h of the thermal injury, and 24 h post‐admission (PA). Enzyme immunoassay techniques were used for the measurement of the neuropeptides. In addition, an inflammatory marker, tumour necrosis factor‐α (TNF‐α), and a myofibrillar protein, creatine kinase (CK), were examined and compared with levels in 13 control subjects.

CGRP was high OA and the levels were maintained PA (P < 0·05). SP was also significantly high at both sampling times (P < 0·05). Although TNF‐α and NPY were somewhat higher in the patients' samples than in the control samples, these levels were not statistically significant (P = NS). CK was higher OA (P < 0·01) than PA (P < 0·04), compared to controls.

Plasma levels of SP and CGRP increased significantly in patients with thermal injuries. These peptides may yet be another group of neuromodulators playing a significant role in immune, pain, inflammatory and wound healing in burns.
Fecal elastase‐1 is decreased in villous atrophy regardless of the underlying disease
Authors: Walkowiak J. , Herzig K‐H.
Published: March 2003

Background Fecal elastase‐1 (E1) is a sensitive and reliable test in the assessment of exocrine pancreatic function in cystic fibrosis (CF). In patients with celiac disease (CD), different E1 values have been reported. E1 levels in other malabsorption conditions are unknown. Therefore, the aim of the present study was to evaluate E1 concentrations in various malabsorption syndromes.

Material and methods The study was carried out in 54 patients, selected from patients referred with suspicion of CF, who had been diagnosed as celiac disease (CD; n = 16), secondary malabsorption syndrome (SMS, giardiasis‐ or cow milk‐related enteropathy; n = 18) and food allergy (FA; n = 20). 70 age‐matched healthy children (HC) and 131 cystic fibrosis (CF) patients served as control groups. In CD and SMS patients, a gluten‐free diet was introduced. In addition, SMS patients were treated appropriately to underlying disease. In all subjects, E1 concentrations were measured. In CD and SMS patients, E1 concentrations were repeatedly measured after one year of the treatment.

Results With a cut‐off level of 200 µg g−1, abnormal E1 concentrations were found in 87·2% of the CF group and in 56·2% and 50·0% of the CD and SMS subgroups, respectively. In none of FA patients, were E1 values below the normal range. After mucosal recovery, E1 concentrations in patients with CD and SMS increased, suggesting that villous atrophy can diminish exocrine pancreatic secretion. In 18 out of 19 CD and SMS patients with abnormal E1 concentrations, monitored for at least 12 months of a gluten‐free diet, abnormal E1 concentrations increased above the cut‐off value to normal range. Two out of the 54 referred patients were finally diagnosed as having CF, one with stable low E1 levels and the second with finally normal values.

Conclusions The exocrine pancreatic function is decreased in villous atrophy regardless of underlying disease. The specificity of the fecal elastase‐1 test in the differentiation between ‘primary’ exocrine pancreatic insufficiency and intestinal malabsorption with mucosal atrophy is low. After mucosal regeneration, fecal elastase‐1 specificity is high.
Noninvasive breath tests can detect alterations in gastric emptying in the mouse
Authors: Symonds E. , Butler R. , Omari T.
Published: March 2003

Background Noninvasive breath tests may have significant utility for the measurement of gastric emptying in mice, but the tests’ sensitivity for detection of changes in gastric emptying has not been evaluated.

Materials and methods Hydroxypropyl methyl cellulose was incorporated into a liquid meal to delay gastric emptying, and mice were injected with erythromycin to accelerate emptying of a liquid or solid meal. All test meals were labelled with 13C‐acetic acid or 13C‐octanoic acid. Breath samples collected at intervals were analysed for 13CO2 content, and gastric emptying rates were calculated from the resultant 13CO2 excretion curves.

Results As predicted, hydroxypropyl methyl cellulose slowed emptying compared with water (14·21 ± 0·94 min vs. 9·17 ± 0·47 min, P < 0·001), while erythromycin treatment accelerated emptying of liquids (10·96 ± 0·78 min vs. 16·41 ± 1·94 min, P < 0·05) and solids (108·81 ± 18·06 vs. 157·95 ± 12·01 min, P < 0·05) compared with the saline injected controls.

Conclusions These data indicate that in mice the breath test is sensitive enough to detect differences in gastric emptying induced by meal composition and pharmacological agents. Noninvasive measurement of gastric emptying in mice will be useful as a method to evaluate the effect of nutrients or drugs on the motility of the gastrointestinal tract.
Immunophenotypic analyses of CD34+ cell subsets in bone marrow from HIV‐infected patients during highly‐ active antiretroviral therapy
Authors: Müller F. , Tjønnfjord G. E. , Nordøy I. , Kvale D. , Mellbye O. J. , Aukrust P. , Frøland S. S.
Published: March 2003

Background Because increased bone marrow lymphopoiesis might contribute to immunologic reconstitution during highly‐active antiretroviral therapy (HAART), we examined the effect of HAART on CD34+ cell subsets in bone marrow from HIV‐infected patients.

Materials and Methods In 12 HIV‐infected patients, bone marrow and peripheral blood were collected before then 4 and 26 weeks after initiating HAART. Bone marrow in 28 HIV‐seronegative controls was also examined. Immunophenotypic analyses of CD34+ cell subsets in bone marrow were performed by flow cytometry.

Results Our main findings in bone marrow were: (i) HIV‐infected patients had increased proportions of CD34+ cells expressing T‐ and B‐cell markers before initiating HAART; (ii) in contrast, these patients had decreased proportions of CD34+ cells expressing myeloid‐associated markers; (iii) although HAART induced an increase in peripheral T‐cell counts, the percentage of CD34+ cells expressing T‐cell markers tended to decrease during such therapy; (iv) HAART induced a decrease in serum IgG accompanied by a slight decrease in the proportion of CD34+ cells expressing B‐cell markers; (v) in contrast, HAART induced a significant increase in peripheral granulocyte counts, accompanied by a slightly increased proportion of CD34+ cells expressing myeloid‐associated molecules.

Conclusion Our findings are compatible with an HIV‐related block in T‐cell differentiation, leading to accumulation of T‐cell progenitors in bone marrow, and such a block may be removed by HAART.
Effect of Simvastatin on markers of triglyceride‐rich lipoproteins in familial hypercholesterolaemia
Authors: Dane‐Stewart C. A. , Watts G. F. , Mamo J. C. L. , Barrett P. H. R. , Martins I. J. , Dimmitt S. B. , Redgrave T. G.
Published: March 2003

Background We have previously shown elevated fasting plasma concentrations of intestinal remnants, as reflected by apolipoprotein (apo) B‐48 and remnant‐like particle‐cholesterol (RLP‐C) in patients with heterozygous familial hypercholesterolaemia (FH). We now investigate the effect of an HMG‐CoA reductase inhibitor (simvastatin) on chylomicron remnant metabolism using the measurement of fasting apoB‐48 and RLP‐C in FH patients after long‐ and short‐term simvastatin therapy and after a wash‐out period. We also piloted the response of a breath test, involving the measurement of the fractional catabolic rate (FCR) of an intravenously injected chylomicron remnant‐like emulsion labeled with cholesteryl 13C‐oleate.

Methods Fifteen FH patients were studied after > 6 months 40 mg day−1 simvastatin treatment (long‐term), a wash‐out period (4 weeks), and 4 weeks of simvastatin treatment (short‐term). Apolipoprotein B‐48 was determined by SDS‐PAGE and Western blotting/enhanced chemiluminescence and RLP‐C by an immunoseparation assay. The FCR of the chylomicron remnant‐like emulsion was determined from the appearance of 13CO2 in the breath and by multicompartmental mathematical modelling.

Results Both long‐ and short‐term treatment with simvastatin were associated with decreases in the plasma concentration of apoB‐48 (P < 0·05) and RLP‐C (P < 0·001), but there was no significant change in the FCR of the emulsion.

Conclusions We suggest that long‐ and short‐term treatments with simvastatin have comparable effects in decreasing the plasma concentration of triglyceride‐rich remnants in heterozygous FH, as measured by fasting apoB‐48 and RLP‐C. The mechanisms for this may involve decreased production of hepatic and possibly intestinal lipoproteins, and/or up‐regulation of hepatic receptor clearance pathways, but these changes are apparently not associated with a change in remnant clearance as measured kinetically by the 13CO2 breath test.
Statins decrease bone turnover in postmenopausal women: a cross‐sectional study
Authors: Rejnmark L. , Buus N. H. , Vestergaard P. , Andreasen F. , Larsen M. L. , Mosekilde L.
Published: March 2003

Background Statins have been suggested as potential agents in the management of osteoporosis. Reviews of medical records have shown an increased bone mass and some studies have shown a reduced occurrence of fractures in subjects on long‐term treatment with statins. We studied the effects of treatment with statins on calcium homeostasis, bone turnover and bone mineral density.

Design In a cross‐sectional design, plasma levels of parathyroid hormone (PTH) and biochemical markers of bone turnover, bone mineral density (BMD) and body composition (fat‐ and lean tissue‐mass) were measured in 140 postmenopausal women who had been treated with a statin for more than 2 years (median 4 years) and compared to 140 age‐ and gender‐matched, population‐based controls.

Results Plasma levels of bone turnover markers were lower in the statin‐treated subjects than in the controls: osteocalcin (−9%, P = 0·03), bone‐specific alkaline phosphatase (−14%, P < 0·01), and C‐terminal telopeptide of type I collagen (−11%, P < 0·01). On the other hand, plasma PTH levels were 16% higher in the statin‐treated subjects than in the controls (P < 0·01). However, body composition and BMD at the lumbar spine, hip, forearm and whole body did not differ between the two groups. No correlation could be demonstrated between changes in biochemical quantities and dose or duration of statin use.

Conclusion Our data show that statins affect the function of bone cells. Most likely, the effect is antiresorptive.
Impaired system A amino acid transport mimics the catabolic effects of acid in L6 cells
Authors: Bevington A. , Brown J. , Butler H. , Govindji S. , M‐Khalid K. , Sheridan K. , Walls J.
Published: March 2003

Background Metabolic acidaemia stimulates protein catabolism in skeletal muscle cells, leading to muscle wasting. As this occurs without decreasing cytosolic pH, the initial signal is unclear. A possible explanation is that extracellular pH acts on solute transporters at the cell surface, inhibiting nutrient influx.

Design Influx through glucose and Pi transporters and System A amino acid transporters into L6 skeletal muscle cells was assessed using 3H‐2‐deoxyglucose (2‐DG), 33Pi and 14C‐methylaminoisobutyrate (MeAIB), respectively. Protein degradation (PD) was assessed from 14C efflux from cells prelabelled with 14C‐Phe. Branched‐chain amino acids and Phe were assayed by selective fluorimetric assays.

Results While acid (pH 7·1) had little immediate effect on 2‐DG or 33Pi influx, exposure to pH 7·1 rapidly inhibited MeAIB influx. To determine whether System A inhibition was sufficient to trigger PD, it was blocked at pH 7·5 by a saturating dose (10 mmol L−1) of nonmetabolisable substrate (MeAIB). Like acid, this increased PD and decreased total protein. It also mimicked the decreases in protein synthesis, DNA synthesis, glucose transport and glycolysis, and depletion of branched‐chain amino acids and Phe, which are induced in L6 by acid. The onset of inhibition of PD by an extracellular Gln load was retarded at pH 7·1, and stimulation of PD by acid was negligible if PD had already been stimulated by Gln depletion. The stimulatory effect of MeAIB on PD was selectively blunted by an excess of Gln, whereas the inhibitory effect of Gln on PD was blocked by excess MeAIB.

Conclusions The similarity of changes in response to MeAIB and acid implies that these share a common intracellular signalling pathway triggered by inhibition of System A. Even though System A is only a minor contributor to total Gln influx in L6 cells, it is suggested that blockade of System A with acid or MeAIB induces a catabolic state by denying Gln access to a key intracellular regulatory site.
Effect of low doses of 5‐methyltetrahydrofolate and folic acid on plasma homocysteine in healthy subjects with or without the 677C→T polymorphism of methylenetetrahydrofolate reductase
Authors: Litynski P. , Loehrer F. , Linder L. , Todesco L. , Fowler B.
Published: March 2003

Background  The 677C→T polymorphism of methylenetetrahydrofolate reductase can lead to increased homocysteine. Moderate increases of homocysteine can be lowered by folic acid (0·4–10 mg day−1). This study compared the effect of folic acid with 5‐methyltetrahydrofolate, the active form of folate generated by this reductase, on homocysteine levels in healthy subjects and whether this is influenced by the 677C→T polymorphism.

Materials and methods  Either 400 µg day−1 of [6RS] 5‐methyltetrahydrofolate or 400 µg day−1 of folic acid were administered orally to 10 wild‐type and 10 homozygous subjects. Total homocysteine and folate were determined before and after 3 and 7 weeks of treatment, and 24 weeks after stopping treatment.

Results  After 3 and 7 weeks of treatment with 5‐methyltetrahydrofolate, homocysteine levels fell from 11·6 ± 1·5 to 9·0 ± 2·3 and 8·7 ± 1·8 (P < 0·005) in wild‐type subjects and from 16·9 ± 6·8 to 12·3 ± 4·3 and 11·6 ± 4·4 µmol/L, mean ± SD (P < 0·005) in homozygous subjects, proving biological availability of 5‐methyltetrahydrofolate irrespective of the 677C→T genotype.

After folic acid for 3 and 7 weeks, values fell from 12·6 ± 3·3 to 9·2 ± 2·9 and 9·2 ± 2·7 (P < 0·005) and from 15·6 ± 4·9 to 11·7 ± 3·9 and 9·1 ± 2·4 µmol L−1, mean ± SD (P < 0·005) in wild‐type and homozygous subjects, respectively.

Six months after stopping treatment, homocysteine levels remained lower than pretreatment levels, with statistical significance, only in homozygous subjects treated with 5‐methyltetrahydrofolate (12·1 ± 2·5 vs. 16·9 ± 6·8, P < 0·01).

Conclusions  5‐methyltetrahydrofolate showed comparable efficacy in reducing homocysteine as folic acid. A prolonged effect 6 months after ceasing treatment with 5‐methyltetrahydrofolate in homozygous subjects represents a further phenotypic effect of the 677TT methylenetetrahydrofolate reductase genotype.
Post‐transcriptional regulation of VEGF expression by oxidised LDL in human macrophages
Authors: Salomonsson L. , Pettersson S. , Englund M. C. O. , Wiklund O. , Ohlsson B. G.
Published: March 2003

Background Accumulation of oxidised low density lipoproteins (oxLDL) in macrophages and their subsequent transformation into lipid‐filled foam cells is generally considered an early event in atherosclerosis. Vascular Endothelial Growth Factor (VEGF) may contribute to atherogenesis through increased vascular permeability, chemoattraction towards monocytes and intraplaque vessel formation. In this study we investigate the effect and regulation of VEGF expression in human macrophages stimulated with oxLDL.

Materials and methods Vascular Endothelial Growth Factor mRNA and protein expression was assayed using RT‐PCR and ELISA, respectively. The activity of mitogen‐activated protein kinases (MAPKs) was investigated using Western blots.

Results In human monocyte‐derived macrophages, oxLDL significantly increased VEGF mRNA expression and subsequent protein secretion in a concentration‐dependent manner after 6 h and 18 h, respectively. Using an in vitro mRNA decay assay, we show that this oxLDL‐induced VEGF expression partly is regulated through increased stability of the VEGF mRNA. Involvement of MAPKs has previously been implicated in the stabilisation of VEGF mRNA. Activity of the p38 MAPK, but not the c‐jun‐N‐terminal kinase (JNK), increased in macrophages stimulated with oxLDL (50 µg mL−1) for 5–15 min. Preincubation with SB202190 (20 µM), a specific inhibitor of p38 MAPK, significantly decreased the oxLDL‐induced VEGF mRNA expression by 40%. The prolonged half‐life of VEGF mRNA, induced by oxLDL, was not inhibited by SB202190.

Conclusions OxLDL increases VEGF expression and p38 MAPK activity in human macrophages. The increased VEGF mRNA expression by oxLDL is mediated through at least two intracellular pathways, one involving p38 MAPK and another that independently of p38 MAPK activity increases VEGF mRNA stability.
Nontransferrin‐bound iron in the plasma of haemodialysis patients after intravenous iron saccharate infusion
Authors: Kooistra M. P. , Kersting S. , Gosriwatana I. , Lu S. , Nijhoff‐Schutte J. , Hider R. C. , Marx J. J. M.
Published: March 2003

Background Many haemodialysis patients treated with recombinant human erythropoietin (r‐HuEPO) receive intravenous iron supplementation on a regular basis. It has been shown previously that this may result in a transient ‘oversaturation’ of transferrin.

Methods Ten stable haemodialysis patients on r‐HuEPO treatment received 100 mg iron saccharate in 60 min, and 1 week later 100 mg in 6 min. Conventional iron metabolism parameters and nontransferrin‐bond iron, detected with HPLC after addition of nitrilotriacetate and pretreatment with cobalt, were measured. Also, iron was measured in dialysate.

Results Serum iron increased from 9·6 ± 6·2 to 213·7 ± 49·4 µmol L−1 (P < 0·001) when iron was given in 60 min, and from 11·1 ± 4·7 to 219·3 ± 43·7 µmol L−1 (P < 0·001) when iron was given in 6 min. Transferrin saturation increased from 0·22 ± 0·18 to 4·75 ± 1·35 in protocol 1 and 0·26 ± 0·16 to 4·91 ± 1·38 in protocol 2. Nontransferrin‐bound iron increased from 0·74 ± 0·69 to 3·79 ± 1·41 µmol L−1 in protocol 1, and from 0·90 ± 0·92 to 2·90 ± 0·96 µmol L−1 in protocol 2. No significant iron concentrations were found in dialysate before or during the iron saccharate infusion.

Conclusion

Nontransferrin‐bound iron exists in plasma of dialysis patients after infusion of iron saccharate. There was no difference when 100 mg iron was given in 60 min or in 6 min. Before iron infusion, appreciable concentrations of nontransferrin‐bound iron could already be detected. The clinical significance is not clear, but the findings may be important since nontransferrin‐bound iron can act as a catalytic agent in the formation of hydroxyl radicals, thus potentially inducing cell damage and atherosclerosis.
Angiostatin prolongs the survival of mice with leptomeningeal metastases
Authors: Reijneveld J. C. , Taphoorn M. J. B. , Kerckhaert O. A. J. , Drixler T. A. , Boogerd W. , Voest E. E.
Published: March 2003

Background As a result of the more effective treatment of primary tumours, the incidence of leptomeningeal metastases (LM) is increasing. Current treatment modalities have little effect on the survival of patients with LM. We investigated whether antiangiogenic treatment inhibits the progression of leptomeningeal tumours.

Materials and methods To assess the role of angiogenesis in leptomeningeal tumours, we inoculated melanoma cells in the subarachnoid space in balb/c mice. At different stages, the mice were sacrificed and the microvessel density was determined. Human specimens of LM were compared with the mouse model. For the intervention studies, the mice were treated with the angiogenesis inhibitor angiostatin. Survival was the endpoint in these studies.

Results Tumour seeding in the early disease stages was concentrated around the pre‐existent arachnoid vasculature. In the more advanced stages, the tumour masses covered larger areas of the leptomeninges. Arachnoidal microvessel density in this advanced stage was increased compared with control mice. Systemic treatment of the mice with LM with angiostatin (100 mg kg−1 day−1) resulted in prolonged survival compared with mice treated with vehicle and with approximately one‐fifth of the long‐term survivors of the angiostatin‐treated group.

Conclusions This study shows that neovascularization is important in the growth of LM in mice. Systemic targeting of the vascular compartment may be a useful approach in novel therapeutic strategies for patients with LM.
Intracellular glutathione and lipid peroxide availability and the secretion of vasoactive substances by human umbilical vein endothelial cells after incubation with TNF‐α
Authors: Scalera F
Published: March 2003

Background The major pathophysiologic changes observed in preeclampsia suggest that endothelial cell dysfunction plays an important role in this disorder. The pathway mediating to endothelial cell dysfunction is unknown, however, the pathogenesis of preeclampsia is thought to be related to increased oxidative stress and increased vasoconstriction. The concentration of tumor necrosis factor alpha (TNF‐α), a cytokine produced by macrophages and many other cell types, has been observed to be significantly increased in preeclampsia. It has been hypothesized that TNF‐α overproduction by the placenta may then may produce an increase in plasma levels and subsequent endothelial dysfunction in preeclampsia. This study investigated the effect of TNF‐α on glutathione and lipid peroxide levels and on the secretion of vasoactive substances by human umbilical vein endothelial cells (HUVECs).

Methods Human umbilical vein endothelial cells were incubated for 24 h in the presence of different concentrations of TNF‐α (0–1000 pg mL−1) that were shown in an earlier experiment to have no effects on the vitality and proliferation rate of HUVECs. The levels of reduced glutathione (GSH) and lipid peroxides (LPOs), assessed by malondialdehyde and 4‐hydroxyalkenal, were measured in endothelial cell lysates. For the measurement of vasoactive substances, levels of prostacyclin (PGI2), determined by 6‐keto‐prostaglandin F1a, thromboxane A2 (TXA2), measured by thromboxane B2, endothelin‐1 (ET‐1), and nitric oxide (NO), measured by total nitrite, were assessed in endothelial cell supernatants.

Results At lower concentrations (10–100 pg mL−1), TNF‐α increases the intracellular content of LPO and GSH, stimulates the secretion of ET‐1 and TXA2, but inhibits the secretion of PGI2 in endothelial cells compared with control cells. At concentration of 1000 pg mL−1, TNF‐α increases the secretion of PGI2 and TXA2, but it decreases the ET‐1 concentration. TNF‐α has no effect on NO secretion.

Conclusion These findings demonstrate that at concentrations corresponding to values in plasma from preeclamptic women, TNF‐α induces oxidative stress and results in altered secretion of vasoactive substances in favour of vasoconstrictors in human endothelial cells. We conclude that TNF‐α may participate in the pathway leading to endothelial cell dysfunction seen in preeclampsia.
HLA class II allele and haplotype distribution in a population from central Poland
Authors: Krokowski M. , Bodalski J. , Bratek A. , Boitard C. , Caillat‐Zucman S.
Published: March 2003

We have studied the distribution of HLA DRB1, DQA1, DQB1 alleles and haplotypes in a sample of 103 unrelated healthy individuals from the region of Lodz in central Poland by the polymerase chain reaction and hybridization with allele‐specific oligonucleotide probes (PCR‐SSO). DRB1*0101, DRB1*07, DRB1*1501, DRB1*03 and DRB1*11 were the most frequent alleles at the DRB1 locus. The DRB1*04 group was observed at a high frequency, but only five out of the 19 DR4 subtypes tested were observed. The most frequent was DRB1*0401, followed by DRB1*0403, DRB1*0402, DRB1*0407 and DRB1*0417. Eight DQA1 alleles were found in this Polish population, among which DQA1*0501, DQA1*0101 and DQA1*0102 were the most frequent. At the DQB1 locus 13 alleles were found. Among them, four were present with frequencies above 10%: DQB1*0201, DQB1*0301, DQB1*0501 and DQB1*0602. Our results underline significant differences between the population of central Poland and populations of neighbouring countries such as Germany, Ukraine and the Czech Republic. This study will serve as a reference for further anthropological studies, as well as studies of associations between HLA and disease.
Human RAGE GLY82SER dimorphism and HLA class II DRB1‐DQA1‐DQB1 haplotypes in type 1 diabetes
Authors: Prevost G. , Fajardy I. , Fontaine P. , Danze P. M. , Besmond C.
Published: March 2003

Advanced glycation end products (AGEs) are believed to play an important role in the development of diabetic complications. AGEs increase in diabetes and modulate cellular functions through binding to a specific cell surface receptor (RAGE). The RAGE gene maps to chromosome 6p in the HLA class III area and is telomeric to the class II region at 250 kb from DRA. A recent report described the characterization of a major RAGE gene variant as a biallelic single base polymorphism (G/A 557) in the exon 3 sequence leading to a change of a glycine to a serine at position 82. Using DGGE and PCR‐RFLP, we have investigated the distribution of this dimorphism in conjunction with HLA class II genes in large populations of type 1 diabetic patients and healthy subjects. Although no association of this RAGE gene polymorphism with disease susceptibility was found, we report a strong linkage disequilibrium between the variant carrying the serine amino acid at position 82 and two HLA‐DR2 and HLA‐DR4 specificities. In particular, we describe two major extensive HLA class II haplotypes associated with this serine variant and identified as DRB1*0401‐DQA1*0301‐DQB1*0301 in the diabetic group and DRB1*1501‐DQA1*0102‐DQB1*0602 in control individuals. These data were partially confirmed by family transmission analysis.
HLA‐DRB1*12 is associated with protection against complicated typhoid fever, independent of tumour necrosis factor α
Authors: Dharmana E. , Joosten I. , Tijssen H. J. , Gasem M. H. , Indarwidayati R. , Keuter M. , Dolmans W. M. V. , Van der Meer J. W. M.
Published: March 2003

We investigated whether HLA‐DR2 or ‐DR12 alleles in 63 Javanese patients with complicated or non‐complicated typhoid fever were associated with severity of disease. No association was observed between HLA type and susceptibility to disease. However, in patients we did find a negative association of DR12 (DRB1*12021) with complicated typhoid fever (P = 0.05; OR = 0.3; 95% CI: 0.1–1.0). No effect of DR2 (DRB1*1502) on outcome (P = 0.46; OR = 1.5; 95% CI: 0.5–4.5) was demonstrated. The odds ratio for DR12 remained unchanged after adjusting for DR2. Tumour necrosis factor α (TNF‐α) production capacity in lipopolysaccharide (LPS)‐stimulated whole blood culture, as measured by non‐equilibrium radioimmunoassay, was significantly lower in complicated than in non‐complicated cases (P = 0.02), confirming previous data. No significant correlation of either DR12 (P = 0.47) or DR2 (P = 0.89) was found with TNF‐α production capacity. Apparently, protection against complications by DR12 is attributable to other mechanisms.
Genotype frequencies of the +874T→A single nucleotide polymorphism in the first intron of the interferon‐γ gene in a sample of Sicilian patients affected by tuberculosis
Authors: Lio D. , Marino V. , Serauto A. , Gioia V. , Scola L. , Crivello A. , Forte G. I. , Colonna‐Romano G. , Candore G. , Caruso C.
Published: March 2003

In the light of the key role played by interferon (IFN)‐γ in the control of tuberculosis, in the present paper we have evaluated the distribution of the functional +874T → A IFN‐γ single nucleotide polymorphism (SNP) in Sicilian patients affected by tuberculosis. Our aim was to determine whether there is an association between the TT genotype, which has been suggested to be linked to an increased production of IFN‐γ, and resistance to chronic tuberculosis. DNA samples were obtained from 45 patients and 97 healthy controls. Polymorphism at +874 was identified using amplification refractory mutational system methodology. The +874T SNP was less frequent in patients than in controls (0.42 vs. 0.50) but the difference was not significant. The +874TT genotype, which has been suggested to be associated with high IFN‐γ production, was significantly decreased in the patients. Thus, resistance to chronic lung tuberculosis might be associated with a genetically determined high IFN‐γ production capacity. In conclusion, the present data add another piece of evidence to the complex puzzle of genetic and environmental factors involved in control of infectious diseases. Studies on cytokine gene polymorphisms may elucidate the complex network of trans‐interactive genes influencing the type and strength of responses to environmental stressors and may help to identify the genetic factors that affect survival in humans.
Allelic frequency of the MCP‐1 promoter −2518 polymorphism in the Korean population and in Korean patients with rheumatoid arthritis, systemic lupus erythematosus and adult‐onset Still's disease
Authors: Hwang S.‐Y. , Cho M.‐L. , Park B. , Kim J.‐Y. , Kim Y.‐H. , Min D.‐J. , Min J.‐K. , Kim H.‐Y.
Published: March 2003

The frequency of the monocyte chemoattractant protein‐1 (MCP‐1) −2518 G‐type polymorphism in Koreans is significantly higher than the frequencies reported for Caucasians and Afro‐Americans. The G‐ vs. A‐allele profile in patients with systemic autoimmune diseases is similar to that in healthy Koreans, and does not appear to contribute to elevated MCP‐1 production in patients.
Prolonged leaching of mineral forest soils with dilute HCl solutions: the solubility of Al and soil organic matter
Authors: BERGGREN  , MULDER  , WESTERHOF
Published: March 2003

Long‐term acidification has been shown to result in a considerable decrease in the amount of organically bound soil Al and in a gradual decrease in the solubility of Al. We examined the solubility of soil organic matter (SOM) and Al in four acid mineral soils (one Arenosol Ah, two Podzol Bh, and one Podzol Bs) as they were leached sequentially using a solution containing 0.001 m HCl and 0.01 m KCl. The acid leaching resulted in relative decreases in Al that were 2–6 times greater than for organic C. The organic C and Al dissolved by the acid leaching originated mainly in the pyrophosphate‐extractable fraction of the elements. Protonation seems to be a major mechanism in stabilizing the residual SOM, as indicated by small changes in effective cation exchange capacity with the degree of acid leaching. In the samples of Podzol Bh and Arenosol Ah soils the solubility of Al (defined as log10{Al3+} + 1.5pH) in equilibrium suspensions (0.01 m KCl) was closely related to the ratio of pyrophosphate‐extractable Al to pyrophosphate‐extractable organic C. The Podzol Bs sample probably contained a small amount of a surface‐reactive Al(OH)3 phase, which rapidly became depleted by the acid leaching.
Transformations of phosphorus during incubation of beech leaf litter in the presence of oxides
Authors: MILTNER A. , HAUMAIER L. , ZECH W.
Published: March 2003

Some minerals have large PO43− sorption capacities. However, we do not know how these mineral phases influence the speciation of organic P when organic matter decomposes. To characterize the interactions between mineral phases and organic P species, we incubated mixtures of beech leaf litter and Fe oxide, Al hydroxide, birnessite, and quartz sand. The samples were extracted with NaOH‐NaF and analysed by 31P nuclear magnetic resonance (NMR) spectroscopy. Phosphate mono‐and diesters gave the most prominent signls in the 31P NMR spectra. During incubation, the proportion of the monoester P decreased, whereas that of the diester P increased. Since NMR intensities assigned to teichoic acids increased, it seems that microbial P accumulated during incubation. The synthesis of microbial compounds was strongest in the presence of Fe oxide. All mineral phases investigated gave rise to a resonance in the 31P NMR spectra which was not present in the control treatment to which the mineral phases had not been added. The resonance was tentatively assigned to sugar diesters, which probably originated from organo‐mineral interactions.
Phosphate‐induced zinc retention in a tropical semi‐arid soil
Authors: AGBENIN J. O.
Published: March 2003

Zinc (Zn) deficiency symptoms and sporadic responses to applied Zn are being observed frequently in the Nigerian savanna, and one cause is thought to be the growing use of phosphorus (P) fertilizers. This study was designed to test the hypothesis of P‐induced Zn retention in the soils. Soil mixed eith P was incubated at field capacity for 3 weeks at 30 ± 2°C. P levels added to the soil were 0, 500, 1000 and 2000 mg per kg soil. After 3 weeks of incubation, water‐soluble Zn in soil decreased by 92% and exchangeable Zn by 78% with 2000 mg kg−1 of applied P. Zn levels ranging from 0 to 200 mg kg−1 were added to the P‐incubated soil to determine the Zn sorption isotherm and retention capacity. The P‐treated soil retained 93 ± 2% of added Zn compared with 52 ± 2% of the control soil. P treatment changed the Zn sorption isotherm from an L‐curve isotherm to an H‐curve isotherm, indicating strong affinity of P‐treated soil for Zn, probably as a result of the formation of Zn‐phosphate complexes on the soil surface and precipitation at sufficiently large concentrations of P and Zn. At 2000 mg P kg−1, up to 90% of Zn retained by the soil was bound in solid form as ZnHPO4. Varying the soil pH from 3.5 to 9.0, Zn retention by the soil was related to Zn hydrolysis with maximum adsorption occurring at pH 7.3 ± 0.2. The dependence of sorbed Zn on Zn(OH)2° at pH 3.5–7.4 of P‐treated soil indicated that significant van der Waals forces might be involved in Zn retention. The implication of the results of this study for the region is that fertilizer‐P placement around a growing crop plant, commonly practised to maximize fertilizer‐P efficiency, can potentially limit Zn solubility and availability.
General purpose Freundlich isotherms for cadmium, copper and zinc in soils
Authors: Elzinga E. J. , Van Grinsven J. J. M. , Swartjes F. A.
Published: March 2003

Assessing the accumulation and transport of trace metals in soils and the associated toxicological risks on a national scale requires generally applicable sorption equations. Therefore Freundlich equations were derived for Cd, Zn and Cu using multiple linear regression on batch sorption data from the literature with a wide variety of soil and experimental characteristics, and metal concentrations ranging over five orders of magnitude. Equations were derived based on both total dissolved metal concentrations and free metal activities in solution. Free metal activities were calculated from total metal concentrations taking into account ionic activity, and inorganic (all metals) and organic complexation (Cu only). Cadmium and Zn were present in solution predominantly as free ions, while Cu was present as organic complexes. Since actual dissolved organic carbon (DOC) concentrations were not available they were estimated using an empirical field relation between DOC and organic matter content. The logarithmic transformation of the Freundlich constant for Cd was regressed on the logarithmic transformations of cation exchange capacity (CEC) (H+) and dissolved Ca, and for Zn with CEC and (H+). For Cu the log–log regression model of the Freundlich constant included the solid:solution ratio of the batch to account for dilution of DOC in the batch as compared with the field. The explained variance for the fitted Freundlich equations was 79% for Cd, 65% for Cu and 83% for Zn, using log‐transformed adsorbed concentrations and soil solution activities. The Freundlich adsorption models underestimated metal contents determined from 1 m HNO3 digestion on field samples, up to a factor of 6 (Cd and Cu) or 10 (Zn).
Measuring bioavailable trace metals by diffusive gradients in thin films (DGT): soil moisture effects on its performance in soils
Authors: Hooda P. S. , Zhang H. , Davison W. , Edwards A. C.
Published: March 2003

Conventional methods of measuring labile chemical species of trace metals in soil solutions, such as chemical competition following centrifuging, are inadequate if the speciation changes during sampling and extraction. A new technique, diffusive gradients in thin films (DGT), measures labile species of trace metals in natural waters and sediments in situ. A well‐defined diffusive gel layer distinguishes it from other resin‐based techniques. It perturbs the soil in a controlled way by introducing an in situ local sink for metal ions. Resulting fluxes to the device are quantitatively measured, allowing assessment of re‐supply kinetics and in some cases measurement of in situ soil solution concentrations. We used DGT to measure fluxes of Cd, Co, Cu, Ni, Pb and Zn in a sludge‐treated soil at various moisture contents (27–106%). Replicate measurements showed that the precision of DGT‐measured fluxes was within 10%. For moisture contents exceeding the field capacity (42%), the DGT response reflected soil water concentrations. At smaller moisture contents, changes related to tortuosity and dilution were reflected in the measurements. This technique has the potential for in situ measurements in the field where it should provide quantitative flux data on individual soils and provide a good surrogate for bioavailable metal.
Statistics to support soil research and their presentation
Authors: Webster R.
Published: March 2003

Much soil research needs statistics to support and confirm impressions and interpretations of investigations in field and laboratory. Many soil scientists have not been trained in statistical method and as a result apply quite elementary techniques out of context and without understanding.

This article concentrates on the most common abuses and misunderstandings and points authors to proper use. It distinguishes variance and standard deviation for measuring dispersion from standard error to indicate confidence in estimates of means. It describes the strictly limited context in which to use the coefficient of variation. It stresses the importance of quoting means and differences between them in contrast to statistical significance, which is at best of secondary interest. It guides readers to inspect and explore their data before deciding to transform them for analysis and illustrates what can be achieved by taking logarithms of single variates and by principal component analysis of multivariate data.
Dissolved organic phosphorus and sulphur as influenced by sorptive interactions with mineral subsoil horizons
Authors: Kaiser K.
Published: March 2003

This study tested the hypothesis that, like dissolved organic nitrogen (N), dissolved organic phosphorus (P) and sulphur (S) are more mobile in soil than is organic carbon (C). To do so, I compared the sorption of organic P and S to subsoil materials with that of organic C. Soil samples were equilibrated with water‐soluble organic matter from the forest floor at pH 4 and in the equilibrium solutions organic C, P, and S, and their distributions between the hydrophilic and hydrophobic fraction were determined. Sorption of C within the organic matter did not differ from that of P and S. However, the hydrophilic fraction contained the vast majority of P and S and sorbed far less than the hydrophobic fraction. So the overall retention of organic P and S was smaller than that of organic C. This result suggested that dissolved organic matter is more important in the loss of plant nutrients than in the release of C from soil.
Heavy metal sorption on soil minerals affected by the siderophore desferrioxamine B: the role of Fe(III) (hydr)oxides and dissolved Fe(III)
Authors: Neubauer U. , Furrer G. , Schulin R.
Published: March 2003

Phytoextraction of heavy metals from polluted soils has often been found to be limited by the bioavailability of the pollutants. Inorganic or organic ligands are occasionally used as complexing agents to enhance the mobility of the heavy metals. However, the opposite effect is also possible. We studied the influence of the hydroxamate siderophore desferrioxamine B (DFOB) on the sorption of Cu, Zn and Cd to clay minerals, with the emphasis on the role of dissolved Fe(III) and Fe(III) minerals. Depending on the surface charge of the minerals and on pH, sorption of heavy metals can be either enhanced or diminished. We show here that this effect of DFOB disappears if dissolved Fe(III) is added to suspensions of clay minerals in excess to DFOB. We found that the solid Fe(III) phases ferrihydrite and goethite did not impede the effect of DFOB on the sorption of heavy metal, however. Between pH 4 and 10, DFOB completely prevented Cu sorption on ferrihydrite. A strong mobilizing effect was also observed for Zn, but not for Cd. In presence of goethite, concentrations of dissolved Cu, Zn and Cd were enhanced only above approximately pH 5, 7 and 8, respectively. Below these pH values the binding of these metals to goethite was even stronger with than without DFOB. In the absence of heavy metals, DFOB‐promoted dissolution of ferrihydrite was much faster than that of goethite due to the larger surface area of ferrihydrite. In the alkaline pH range, where sorption of DFOB on the surfaces of the iron oxides was greater, dissolution of both minerals was reduced.
Robust estimation of the pseudo cross‐variogram for cokriging soil properties
Authors: Lark R. M.
Published: March 2003

The pseudo cross‐variogram can be used for cokriging two or more soil properties when few or none of the sampling locations have values recorded for all of them. The usual estimator of the pseudo cross‐variogram is susceptible to the effects of extreme data (outliers). This will lead to overestimation of the error variance of predictions obtained by cokriging. A solution to this problem is to use robust estimators of the pseudo cross‐variogram, and three such estimators are proposed in this paper.

The robust estimators were demonstrated on simulated data in the presence of different numbers of outlying data drawn from different contaminating distributions. The robust estimators were less sensitive to the outliers than the non‐robust one, but they had larger variances. Outliers tend to obscure the spatial structure of the cross‐correlation of the simulated variables as described by the non‐robust estimator.

The several estimators of the pseudo cross‐variogram were applied to a multitemporal data set on soil water content. Since these were obtained non‐destructively, direct measurements of temporal change can be made. A prediction subset of the data was subsampled as if obtained by destructive analysis and the remainder used for validation. Estimators of the auto‐variogram and pseudo cross‐variogram were applied to the prediction data, then used to predict the change in water content at the validation sites by cokriging. The estimation variances of these predictions were best calculated with a robustly estimated model of coregionalization, although the validation set was too small to conclude that the non‐robust estimators were unsuitable in this instance.