bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyperlipoprotein(a)aemia in nephrotic syndrome
Authors: THIERY J. , IVANDIC B. , BAHLMANN G. , WALLI A. K. , SEIDEL D.
Published: November 2003

The nephrotic syndrome is frequently associated with hyperlipidaemia and hyperfibrinogenaemia, leading to an increased coronary and thrombotic risk, which may be enhanced by high lipoprotein (a) [Lp(a)] concentrations. We followed the quantitative and qualitative pattern of plasma lipoproteins over 18 months in a patient with nephrotic syndrome suffering from premature coronary artery disease and with elevated level of Lp(a) (470 mg dL−1). Analysis of kinetic parameters after heparin‐induced extracorporeal plasma apheresis revealed a reduced fractional catabolic rate for both low‐density lipoprotein (LDL) and Lp(a). After improvement of the nephrotic syndrome, Lp(a) decreased to 169 mg dL−1 and LDL concentrations were normalized. The decrease of Lp(a) was associated with an increase in plasma albumin concentrations. Analysis of apo(a) isoforms in the patient showed the presence of isoform S2 (alleles 10 and 19). Consequently, the authors’ present strategy is to normalize the elevated Lp(a) and fibrinogen levels. For this purpose heparin‐mediated extracorporeal LDL precipitation (HELP) apheresis is a promising regimen, helping to reduce the thrombotic risk and prevent coronary and graft atherosclerosis as well as the progression of glomerulosclerosis in our patient.
Measurement of post‐absorptive glucose kinetics in non‐insulin‐dependent diabetic patients: methodological aspects
Authors: RIGALLEAU V. , BEYLOT M. , LAVILLE M. , GUILLOT C. , DELERIS G. , AUBERTIN J. , GIN H.
Published: November 2003

Post‐absorptive glucose metabolism was studied in non‐insulin‐dependent diabetes mellitus (NIDDM) patients and normal subjects using dideuterated glucose as tracer. From the progressive fall in blood glucose levels and the increase in isotopic enrichment, the post‐absorptive situation could not be regarded as a steady state for glucose metabolism, and non‐steady‐state approximations had therefore to be applied. However, this did not alter significantly the results in the 10 NIDDM patients studied. Significantly higher values of endogenous glucose production (EGP) were obtained (178.1 ± 24.0 mg m−2 min−1 vs. 80.2 ± 14.4; P < 0.01) if the tracer priming dose was not adapted to the degree of hyperglycaemia. Valid measurements could be made after only 1 h isotopic equilibration time if an appropriately matched priming dose was employed. Methodologically acceptable values for EGP in the 10 NIDDM patients did not differ significantly from those of 10 normal control subjects (80.2 ± 14.4 mg m−2 min−1 vs. 85.6 ± 3.9; not significant). The post‐absorptive hyperglycaemia in these patients was assumed to stem essentially from a defect in peripheral glucose uptake.
The effect of folic acid on the homocysteine metabolism in human umbilical vein endothelial cells (HUVECs)
Authors: VAN DER MOLEN E. F. , VAN DEN HEUVEL L. P. W. J. , TE POELE POTHOFF M. T. W. B. , MONNENS L. A. H. , ESKES T. K. A. B. , BLOM H. J.
Published: November 2003

Mild hyperhomocysteinaemia is associated with increased risk for vascular disease. We studied homocysteine export from human umbilical vein endothelial cells (HUVECs) by measuring total homocysteine (tHcy) concentrations in the culture medium. Under standard culture conditions tHcy concentrations in the HUVEC culture medium increased by constant amounts after 24, 48 and 72 h [mean = 2.5 (SD ± 0.7) μmol L−1 homocysteine every 24 h]. As the cells are the only source of homocysteine increase in the culture medium, we designate this as homocysteine export from HUVEC. Folic acid supplementation to the culture medium lowered the homocysteine export in a dose‐dependent manner. Methyl‐tetrahydrofolate (MeTHF) and folinic acid (a stable precursor of MeTHF) were in this respect about 10 times more effective than folic acid. A 50% reduction in the homocysteine export was seen with 10–30 nmol L−1 MeTHF supplementation; reduction to almost zero was seen with 100–300 nmol L−1 MeTHF. Additions to the culture medium of the other vitamins involved in the homocysteine metabolism, such as vitamin B12, vitamin B6 and flavin adenine dinucleotide, did not show any effect on homocysteine export. Because homocysteine export reflects an imbalance in the homocysteine metabolism, our observations showed a susceptible dependency of this metabolism on folic acid in endothelial cells.
Acute hyperinsulinaemia decreases cholesterol synthesis less in subjects with non‐insulin‐dependent diabetes mellitus than in non‐diabetic subjects
Authors: NAOUMOVA R. P. , CUMMINGS M. H. , WATTS G. F. , RENDELL N. B. , TAYLOR G. W. , SÖNKSEN P.  H. , THOMPSON G. R.
Published: November 2003

To investigate the effect of insulin on cholesterol synthesis in vivo we measured plasma mevalonic acid (MVA) concentrations using gas chromatography–mass spectrometry in six non‐obese patients with non‐insulin‐dependent diabetes mellitus (NIDDM) [four men, two women; age 57.5±2.2 years (mean±SEM); glycated haemoglobin (HbA1) 8.5±0.5%; total cholesterol (TC) 5.7±0.5 mmol L−1, triglyceride (TG) 3.8±0.9 mmol L−1] and six non‐diabetic, sex‐ and age‐matched control subjects (age 55.7±2.8 years; HbA1 6.5±0.1%; TC 5.4±0.3 mmol L−1, TG 1.2±0.1 mmol L−1). Subjects were studied twice: during 13‐h hyperinsulinaemic (1 mu kg−1 min−1), euglycaemic (5 mmol L−1) clamp and during a saline infusion. Baseline MVA concentration was significantly higher in diabetic patients than in control subjects (9.8±0.7 ng mL−1 vs. 5.6±0.9 ng mL−1P=0.004). At the end of each study, MVA concentration, expressed as a percentage of baseline, was significantly lower during the hyperinsulinaemic, euglycaemic clamp than during the saline study in both the diabetic (54.4±5.3% vs. 69.6±6.3%, P=0.036) and control subjects (30.5±3.4% vs. 61.7±6.0%, P=0.01). However, the decrease in MVA during the hyperinsulinaemic clamp study was more marked in the control subjects than in the diabetic subjects (P=0.03). A significant positive correlation was found between percentage decrease of MVA and non‐esterified fatty acids following the insulin clamp in NIDDM (r=0.83, P=0.04). We conclude that acute hyperinsulinaemia decreases cholesterol synthesis less in subjects with NIDDM than in non‐diabetic subjects and that this phenomenon, together with increased basal cholesterol synthesis in NIDDM, may in part be due to insulin resistance.
Bone alkaline phosphatase measured with a new immunoradiometric assay in patients with metabolic bone diseases
Authors: Gonnelli S. , Cepollaro C. , Montagnani A. , Monaci G. , Campagna M. S. , Franci M. B. , Gennari C.
Published: November 2003

We have investigated the clinical utility of a new quantitative two‐site radioimmunometric assay specific for bone alkaline phosphatase (B‐ALP) in 219 healthy control subjects and in 264 patients with various metabolic bone diseases. B‐ALP was compared with total alkaline phosphatase (T‐ALP) and with osteocalcin (BGP). B‐ALP increased linearly with age in both sexes. In postmenopausal normal women B‐ALP increased by 82% compared with premenopausal normal women, whereas the differences between pre‐ and postmenopausal women for T‐ALP and BGP were 18% and 30% respectively. As assessed by Z‐score, the highest values of B‐ALP were found in patients with Paget's disease of bone, bone metastases or hyperparathyroidism and in patients on maintenance haemodialysis. In osteoporotic patients, B‐ALP, but not T‐ALP, showed a slight but significant (P < 0.05) difference compared with normal women. On the basis of bone turnover, osteoporotic patients were divided into two groups: high turnover and low turnover; B‐ALP, like BGP, was significantly (P < 0.01) higher in patients with high turnover. In conclusion, B‐ALP, measured by this new method, can be considered a sensitive marker of bone turnover and could be especially useful in identifying women at risk of developing osteoporosis.
Arginine, lysine and ornithine as vasodilators in the forearm of man
Authors: RHODES P. , BARR C. S. , STRUTHERS A. D.
Published: November 2003

Nitric oxide is an endogenous vasodilator produced from l‐arginine and oxygen by stereospecific enzymes. l‐arginine itself can act as a vasodilator when administered at high doses to humans. This effect has been attributed by some to provision of extra substrate for production of nitric oxide. This work compares l‐arginine‐induced vasodilation with that caused by d‐arginine, hyperosmolar sodium chloride and by other cationic amino acids in the resting forearm vasculature of normal subjects. By these means we identify whether l‐arginine‐induced vasodilation has a component related to stereospecific provision of substrate for nitric oxide production, or whether it can be accounted for by other phenomena. Effects of hyperosmolar sodium chloride and both l and d isomers of arginine, lysine and ornithine on forearm blood flow in eight normal male subjects were compared by bilateral forearm venous occlusion plethysmography. Vasodilator responses to saline and each amino acid were compared as the area under dose–response curves with single‐factor analysis of variance (anova). The magnitude of vasodilation obtained with the d isomers of each amino acid was compared with the l counterpart by application of single‐factor anova to the appropriate areas under dose–response curves. All three cationic amino acids increased forearm blood flow. Part of the increase could be related to the high osmolality of infusates—comparison with equiosmolar sodium chloride solutions shows that ornithine does not differ significantly as a vasodilator (P > 0.4), but that arginine and lysine have greater vasodilator effects than can be accounted for by osmolality alone (P < 0.001). The d isomers of arginine and lysine were more potent dilators than their l counterparts (arginine P < 0.03, lysine P < 0.02). The vasodilator effects of arginine in the forearm vascular bed at rest are not stereospecific, they are common to other cationic amino acids, greater for d isomers and occur only when normal plasma concentrations are raised far above the physiological range. These features suggest that the vasodilator effect of arginine is in part physical and related to the presence of the molecule in the vessel lumen. They do not suggest that increased provision of substrate, with a consequence of increased nitric oxide production, is the principal basis of l‐arginine‐induced vasodilation in normal humans.
Identification of oestrogen receptors and oestrogen receptor mRNA in human adipose tissue
Authors: PEDERSEN S. B. , HANSEN P. S. , LUND S. , ANDERSEN P. H. , ODGAARD A. , RICHELSEN B.
Published: November 2003

The distribution of adipose tissue has a major impact on the morbidity and mortality associated with obesity. Furthermore, the distribution of adipose tissue seems to be regulated by sex hormones. Controversy exists over whether the effects of sex hormones (oestrogen and testosterone) on human adipose tissue are an indirect or a direct effect as contradictory results have been obtained when investigating the existence of these receptors in human adipose tissue. In the present study the authors reinvestigated the possible existence of oestrogen receptors (ERs) in human adipose tissue. Human adipocytes from both genders were found to contain specific oestrogen binding sites determined by ligand‐binding techniques. The binding protein had a molecular weight of 65 kD (which is similar to that of the ER found elsewhere) and it was found that adipocytes contained mRNA encoding the ER. Moreover, human preadipocytes had no oestrogen‐binding capacity and did not possess mRNA encoding the ER. Finally, the authors detected regional differences in receptor density. Women had an equal oestrogen‐binding capacity in adipose tissue from the subcutaneous abdominal and the visceral depot, whereas men had twice as high oestrogen‐binding capacity in subcutaneous adipose tissue compared with adipose tissue in the visceral fat depot. These findings indicate that mature human adipocytes possess ERs and thus, might be an oestrogen‐ responsive tissue and that oestrogen may be acting directly in mature adipocytes via its specific receptor. Human preadipocytes, however, seemed not to be an oestrogen‐responsive tissue. Finally, preliminary data suggest that there might be differences in ER densities in different fat depots.
Role of catecholamines in platelet function: pathophysiological and clinical significance
Authors: ANFOSSI G. , TROVATI M.
Published: November 2003

Platelets are involved in the pathogenesis of vascular damage in both atherosclerosis and arterial hypertension. Their reactivity in vivo is influenced by different factors, including sympathoadrenal activation, plasma levels of atherogenic lipoproteins and haemorrheological changes. In the present review, we examine the modulation of platelet function by the sympathoadrenal system and concentrate on the role of circulating catecholamines in the control of platelet responses. Human platelets exhibit both adrenergic and dopaminergic receptors that are influenced by different catecholamines. α2‐Adrenoceptors of α2A subtype prevail on platelet membrane; through their stimulation, catecholamines potentiate the effects of other agonists and, at higher concentrations, initiate platelet responses, including aggregation, secretion and arachidonate pathway activation. Physiological and pathological conditions causing sympathoadrenal activation in vivo, i.e. physical activity, mental stress, insulin‐induced hypoglycaemia, acute coronary ischaemia and heart failure, modify the circulating platelet populations and modulate platelet reactivity through an increase in circulating catecholamines. A sympathoadrenal hyperactivation modifies the function of circulating platelets through direct catecholamine effects, catecholamine‐induced changes of haemodynamic factors and lipid pattern and inhibition of the vascular eicosanoid synthesis. The catecholamine effects on platelet function can be involved in the interplay among stress, adrenomedullary system activation and cardiovascular diseases.
Nerve conduction velocity in human limbs with late sequelae after local cold injury
Authors: ARVESEN A. , WILSON J. , ROSÉN L.
Published: November 2003

Cold‐induced neuropathy may play a dominant role in the long‐term sequelae with cold sensitivity after local cold injuries (LCIs). Somatosensory functions were assessed and nerve conduction velocity (NCV) and motor distal delay (MDD) were measured in the limbs of 31 Norwegian former soldiers with persistent cold intolerance 3–4 years after the primary LCI. NCV measurements were performed in 24 lower and 16 upper extremities. NCV was related to degree of overall subjective complaints quantified by means of a visual analogue scale (VAS). Motor (MNCV) and sensory conduction velocity (SNCV) in the lower extremities and SNCV in the hands were significantly decreased compared with controls. MDD was pathologically increased in the feet. NCV of the forearms ranged from normal to significant reduction. The more pronounced effect on the lower extremities may be caused by deeper cooling of the calves compared with forearms for several reasons. No significant associations were found between VAS and NCV except for the right median nerve. NCV measurements may provide objective findings in cold‐injured patients and in those with few or no conspicuous clinical signs.
Elevated plasma adrenomedullin level in hyperthyroidism
Authors: TANIYAMA M. , KITAMURA K. , BAN Y. , ETO T. , KATAGIRI T.
Published: November 2003

Adrenomedullin is a recently discovered peptide that was first purified from phaeochromocytoma tissue and has marked vasodilatory activity, causing hypotension. In thyrotoxicosis, various haemodynamic changes are observed, including an increase in cardiac output and heart rate with a concomitant decrease in peripheral vascular resistance. To evaluate the mechanism underlying these haemodynamic changes in thyrotoxicosis, we measured the plasma adrenomedullin concentration in thyrotoxic patients with Graves' disease. The plasma concentration of adrenomedullin was elevated in hyperthyroid patients (14.7±5.7pmolL−1) compared with euthyroid control subjects (5.6±1.3pmolL−1) (P<0.001). The correlation between the plasma adrenomedullin concentration and serum free thyroid hormone levels was marginally significant. The mean blood pressure was relatively low in the face of an elevated plasma adrenomedullin level. Adrenomedullin may therefore be responsible for the vasodilatation observed in thyrotoxicosis.
Immunochemical and biomolecular studies of circulating immune complexes isolated from patients with acute and chronic hepatitis C virus infection
Authors: SANSONNO D. , IACOBELLI A. R. , CORNACCHIULO V. , LAULETTA G. , DISTASI M. A. , GATTI P. , DAMMACCO F.
Published: November 2003

Circulating immune complexes (ICs) were isolated by affinity chromatography and sucrose density gradient fractionation during acute and chronic hepatitis C virus (HCV) infection. Immunochemical and biomolecular studies showed that they basically consist of the virus component, IgG with specific anti‐HCV activity and IgM bearing 17.109 epitope (IgM 17.109), an antigenic determinant common to rheumatoid factors (RFs) with WA cross‐idiotype (XId). An antigen‐specific IC assay was used to demonstrate IgG anti‐HCV/IgM 17.109 ICs (IgG‐IgM ICs) in five out of the five patients with acute and in 8 out of the 10 patients with chronic hepatitis C who mounted an IgG anti‐HCV immune response. They were not detected in patients with no IgG anti‐HCV response. IgG–IgM ICs appeared in step with IgG anti‐HCV seroconversion and remained detectable for a long period irrespective of clinical outcome, in that they were demonstrated over a 4‐year follow‐up of patients with chronic hepatitis C. Their presence was unrelated to the severity and progression of liver histology. Despite similar serum levels of IgM 17.109 XId, antigen‐specific IgG‐IgM ICs were not found in acute and chronic hepatitis B or in acute hepatitis A. Thus, these ICs appear to be uniquely associated with HCV infection, supporting the view that IgM 17.109 XId derive from an antigen‐driven response strictly related to the involved antigen. Even although they have no apparent effects on the progression of HCV‐related liver disease, their presence may help to explain the immunological abnormalities and extrahepatic disorders observed in HCV infection.
The effect of the menstrual cycle on exhaled nitric oxide and urinary nitrate concentration
Authors: MORRIS N. H. , SOORANNA S. R. , STEER P. J. , WARREN J. B.
Published: November 2003

Exhaled nitric oxide (NO), early morning urinary nitrites/nitrates and urinary female sex steroid conjugates were measured daily to investigate whether there was a variation in NO generation during the menstrual cycle. Exhaled NO concentrations and early morning urine samples were taken for 30 consecutive days in five healthy normotensive women with proven ovulation. The urine samples were analysed for nitrite–nitrate creatinine ratios, oestrone‐3‐glucuronide (EG) and pregnanediol‐3‐alpha glucuronide (PG). The mean (95% CI) exhaled NO concentration was 52 ng g−1 in the 150 readings and the mean molar urinary nitrate–creatinine ratio was 0.18. There was no temporal relationship between the measurement of NO production and urinary sex steroid conjugates within the menstrual cycle. These findings suggest that oestrogens do not modulate exhaled NO concentration and appear not to increase the production of the early morning urinary nitrates in healthy premenopausal women. There was also no sex difference in exhaled NO generation.
Absence of cholesteryl ester transfer protein‐mediated cholesteryl ester mass transfer from high‐density lipoprotein to low‐density lipoprotein particles is a major feature of combined hyperlipidaemia
Authors: GUéRIN M. , BRUCKERT É. , DOLPHIN P. J. , CHAPMAN M. J.
Published: November 2003

Elevated plasma cholesteryl ester transfer protein (CETP) mass is characteristic of combined hyperlipidaemia (CHL), an atherogenic dyslipidaemia characterized by increased levels of both very low‐density lipoprotein (VLDL) and low‐density lipoprotein (LDL) and subnormal levels of high‐density lipoprotein (HDL). CETP remodels plasma lipoproteins by promoting the heteroexchange of neutral lipids. To determine the mechanism of the CETP‐mediated redistribution of cholesteryl ester (CE) between plasma lipoprotein particles in CHL, we measured CE mass transfer and exchange from HDL to apoB‐containing lipoproteins under physiological conditions in the plasmas of 14 CHL patients and compared the data with those in a group of normolipidaemic subjects (NLS; n=9). The rate of CE mass transfer from HDL to VLDL was significantly increased in CHL patients (24.1 ± 3.8 μg CE transferred h−1 mL−1 plasma) when compared with NLS (14.4±2.6 μg CE transferred h−1 mL−1 plasma, P=0.0001). By contrast with control subjects, no net CE mass transfer from HDL to LDL was detected in CHL patients; transfer of radiolabelled CE to LDL was, however, observed, suggesting the occurrence of CE exchange between HDL and LDL in the absence of net CE mass transfer. The LDL fraction from CHL patients displayed a significant reduction (15%; P<0.003) in its ability to accept cholesteryl ester from HDL when compared with normolipidaemic LDL. Moreover, a reduction of 10% (P<0.02) was found in the capacity of hyperlipidaemic HDL to donate cholesteryl esters to apoB‐containing lipoproteins as compared with control HDL; the reduced levels (–32%) of HDL2b particles in CHL plasmas may account for this effect. We conclude that the low affinity of hyperlipidaemic LDL particles for CETP, taken together with the elevated plasma concentrations of a qualitatively active CE acceptor, VLDL, and the low HDL levels in CHL patients, result in the absence of net CE mass transfer from HDL to LDL in Combined hyperlipidaemia.
Activation of endothelial cells during insulin‐dependent diabetes mellitus: a biochemical and morphological study
Authors: Cester N. , Rabini R. A. , SALVOLINI E. , Staffolani R. , CURATOLA A. , Pugnaloni A. , Brunelli M. A. , Biagini G. , Mazzanti L.
Published: November 2003

Plasma membrane lipid dynamics and cellular morphology were evaluated in endothelial cells obtained from umbilical cords of five women affected by insulin‐dependent diabetes mellitus (IDDM) and six healthy pregnant women of similar age and gestational age. Endothelial cells were prepared by an adaptation of the method of Jaffe et al. Membrane fluidity was studied by means of the steady‐state fluorescence anisotropy (r) of 1‐(4‐trimethylaminophenyl)‐6‐phenyl‐1,3,5‐hexatriene (TMA‐DPH), a fluorescent probe specifically anchoring at the membrane surface. Fluid phase endocytosis was evaluated by the measurement of the changes in fluorescence intensity of TMA‐DPH at various times, owing to the internalization of the fluorescent marker in endocytic vesicles. The morphological and morphometric studies were performed by means of transmission electron microscopy (TEM). Endothelial cells obtained from IDDM women showed: (a) increased fluidity of the superficial region of the plasma membrane; (b) a more active fluid phase endocytosis compared with cells from healthy women; (c) increase in mitochondrial area, Weibel–Palade bodies and rough reticulum with wide cisternae. No statistically significant correlation was found between metabolic control and membrane fluidity and endocytosis. All the observed modifications suggest the presence of endothelial cell activation with membrane reshaping during IDDM. These alterations might play a central role in the pathophysiology of atherosclerosis and microangiopathy associated with diabetes mellitus.
Detection of gram‐negative bacteraemia in early sepsis by a quantitative chromogenic and kinetic endotoxin assay
Authors: MASSIGNON D. , LEPAPE A. , DEBIZE G. , REMILLIEUX M. F. , DE PASQUALE V. , BANSSILLON V. , CŒUR P. ,   THE STUDY GROUP
Published: November 2003

A kinetic chromogenic limulus test was carried out in order to investigate the possibility of a sensitive and specific detection of circulating endotoxin during the first 24 h of septic shock or severe sepsis in 76 patients. Two commercial kits, Whittaeker (W) and Chromogenix (C), were used. Blood culture was taken as a reference. At 1 : 10 plasma dilution (a currently used dilution in the end point limulus test) abnormal reaction kinetics were found in 13% and 41% of tests, for C and W respectively (P = 0.0008), resulting in unreliable results. Retesting plasma at a greater dilution, until the reaction kinetic was identical to calibration curve control values, gave similar results between the two kits and a better accuracy. Beyond a 0.5 EU mL−1 endotoxin level, the probability of Gram‐negative bacteraemia was high (sensitivity = 0.53 and 0.47; specificity = 0.95 and 0.93 for C and W respectively). This kinetic limulus amoebocyte lysate (LAL) test may be useful in therapeutic decisions for treatment of endotoxaemia.
Effects of bile salt hydrophobicity on crystallization of cholesterol in model bile
Authors: VAN ERPECUM K. J. , PORTINCASA P. , GADELLAA M. , VAN DE HEIJNING B. J. M. , VAN BERGE HENEGOUWEN G. P. , RENOOIJ W.
Published: November 2003

Precipitation of cholesterol crystals is an essential step in gallstone formation. In the present study we found much faster and more extensive precipitation of various cholesterol crystal shapes in whole model biles containing the hydrophobic bile salt taurodeoxycholate than in biles containing the relatively hydrophilic taurocholate. Addition of taurodeoxycholate to isolated cholesterol–phospholipid vesicles also induced more crystallization than taurocholate. Crystallization behaviour in whole model biles and in vesicles after addition of corresponding bile salts was very similar. The very hydrophilic bile salts tauroursodeoxycholate and taurohyodeoxycholate never induced crystallization from vesicles, and crystallization in corresponding whole model biles did not occur. These bile salts also reduced crystallization dose dependently after addition of taurodeoxycholate to vesicles. Ultracentrifugation experiments suggested a higher vesicular cholesterol–phospholipid ratio for whole model biles containing more hydrophobic bile salts. These findings indicate that bile salt hydrophobicity influences shape of cholesterol crystals and extent of crystallization, possibly by modulating the vesicular cholesterol–phospholipid ratio.
Red blood cell aggregability is increased by aspirin and flow stress, whereas dipyridamole induces cell shape alterations: measurements by digital image analysis
Authors: Bozzo J. , Hernández M. R. , del Giorgio A. , Ordinas A.
Published: November 2003

We evaluated the influence of pretreatment with aspirin in vitro, alone or combined with dipyridamole, on red cell aggregability. Samples were tested before and after being exposed to well‐defined flow conditions. An aggregation rate was estimated through digital analysis of light microscopy images. Red cells of untreated blood that had been exposed to flow showed a higher aggregation rate (38.54 ± 1.63 vs. 27.52 ± 1.36; P < 0.05). This effect was not observed in the absence of platelets. Treatment with aspirin induced a high aggregation rate, with or without exposure to flow conditions. Dipyridamole alone or combined with aspirin provoked echinocytosis, disturbing the rouleaux arrangement (rates ranging from 11.25 ± 1.91–13.62 ± 1.62). Washing red cells after treatment restored about 90% of echinocytes to their biconcave shape, but aggregation rate did not recover in parallel. These results highlight the influence of red cell–platelet interactions in the regulation of haemostasis and show how therapeutic agents can interfere with rheological phenomena.
Utilization of myristic and palmitic acid in humans fed different dietary fats
Authors: MacDougall D. E. , Jones P. J. H. , Vogt J. , Phang P. T. , Kitts D. D.
Published: November 2003

To assess the influence of dietary fat composition on the contribution of dietary myristic and palmitic acid to total fat oxidation and energy production, eight healthy men consumed diets containing 40% of total energy as fat, largely as either butter, tallow or corn oil, for 11 days. On days 8 and 11 of each diet, [1‐13C]‐myristic or [1‐13C]‐palmitic acid (20 mg kg–1 body weight) was ingested mixed with the test breakfast meal. Respiratory gas exchange was measured before, and for 9 h after, consumption of the meal. Breath 13CO2 enrichments were determined hourly by isotope ratio mass spectrometry. Cumulative 9‐h percentage oxidation of dietary myristic acid exceeded that of palmitic acid (P < 0.01), but neither was influenced by fat treatment [n = 8, 7.1% (1.0) (SEM), 8.6% (0.9) and 8.9% (0.6) of dietary myristic acid and 3.3% (0.7), 3.0% (0.9), and 2.5% (0.6) of dietary palmitic acid from butter, tallow and corn oil meals respectively]. Net dietary myristic acid oxidation was greater (P <0.05) after consumption of the meal high in butter than after consumption of other fats. Net dietary palmitic acid oxidation was similar after consumption of all test meals. Precedent fat treatment had no measurable effect on net fat or carbohydrate oxidation or energy expenditure. The overall contribution of dietary myristic or palmitic acid to total fat oxidation did not exceed 1% over 9 h for any dietary fat. These results suggest that, although dietary fatty acid content is the principal determinant of net dietary fatty acid oxidation, dietary fat sources with moderate differences in fat composition do not measurably alter total energy or substrate utilization after a meal.
A simple, rapid immunometric assay for determination of functional and growth hormone‐occupied growth hormone‐binding protein in human serum
Authors: FISKER S. , FRYSTYK J. , SKRIVER L. , VESTBO E. , HO K. K. Y. , ØRSKOV H.
Published: November 2003

We present a sensitive time‐resolved fluorometric immunofunctional assay (TR‐FIA) for direct quantitation of functional growth hormone‐binding protein (GHBP), using an immunoassay kit for growth hormone (GH‐DELFIA). In addition to the immobilized GH antibody, one monoclonal antibody against GHBP was used. This anti‐GHBP was labelled with the chelate of europium. The assay was performed in one step. The detection limit for GHBP was 0.044 nmol L–1 (NBS + 3 SD). The calibration curve was linear in the interval 0.11–8.03 nmol L−1. Average intra‐assay coefficient of variation (CV) was 3.44%. Average interassay CV at GHBP concentrations 0.563 nmol L−1 and 1.40 nmol L−1 were 12% and 6.3% respectively. Analytical recovery in serum ranged from 76% to 127% with a mean of 101 ± 3.6%. Serum GHBP in 102 normal subjects ranged from 0.513 to 3.772 nmol L 1 and was positively related to body mass index (P < 0.001). In growth hormone‐deficient sera GHBP was higher than in control subjects (1.751 ± 0.179 nmol L−1 and 1.257 ± 0.140 nmol L−1 respectively, P < 0.001). Acromegalic patients had lower levels of GHBP than controls (0.946 ± 0.251 and 1.234 ± 0.144 nmol L−1 respectively, P = 0.005). This assay also allowed detection of GH‐complexed GHBP in serum. These results were in agreement with theoretical values calculated from the measured GH and the functional GHBP concentrations. Results were compared with data obtained by a recently reported, validated ligand immunofunctional assay (LIFA), which is fundamentally different. There was a significant linear relationship between the results from the two assays (r = 0.89, P = 0.001). The slope of the regression line was 0.65. In conclusion, this new convenient GHBP TR‐FIA provides a sensitive and precise method for detecting total GHBP as well as complexed GHBP in human serum, and allows easy processing of large numbers of samples.
Vitamin D receptor genotypes are related to bone size and bone density in men
Authors: Need A. G. , Horowitz M. , Stiliano A. , Scopacasa F. , Morris H. A. , Chatterton B. E.
Published: November 2003

Three restriction fragment length polymorphisms in the vitamin D receptor gene have been associated with a low bone density in twin and female population studies, but no studies have been conducted exclusively in men. We studied 146 normal men aged 20–83 years. Bone density was measured in the spine, hip, whole body and forearm, and the Bsm polymorphism for the vitamin D receptor was detected by the polymerase chain reaction. Men with genotype BB tended to have a lower bone density at all but one site than the other genotypes. In the men ≤50 years of age bone density in the forearm was 7% lower in the BB than the Bb and bb groups (P  =  0.030) but bone mineral content did not differ between the groups. Bone area was greater in the BB genotype at all sites. This was statistically significant in the forearm (P  =  0.026). We conclude that BB genotype is associated with lower bone density in men, which may be due to larger bone size rather than reduced bone mass.
Synthesis and release of phosphatidylcholine by isolated porcine gastric mucous cells in primary culture
Authors: Bernhard W. , Schulte H. , Piller M. , Sewing K.‐F.
Published: November 2003

Phosphatidylcholine (PC) is the major phospholipid of the hydrophobic gastric mucosal barrier and is chiefly released from mucous cells into the gastric mucus. Whereas the mucosa contains highly unsaturated PC, gastric mucus predominantly contains palmitoyl‐oleoyl‐PC and palmitoyl‐linoleoyl‐PC, indicating a selective release of these PC species into the gastric lumen. In order to understand gastric PC metabolism, we investigated synthesis and release of PC in cultivated porcine gastric mucous cells, using dual labelling with [methyl‐3H]‐choline and [1‐14C]‐palmitate, in the presence of 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), indomethacin and prostaglandin E2 (PGE2). Linear incorporation of [methyl‐3H]‐choline and [1‐14C]‐palmitate into PC was achieved for at least 8 h. In contrast to type II pneumocytes TPA increased PC synthesis in gastric mucous cells but not its release. Indomethacin did not influence PC synthesis, but it decreased the release of newly synthesized PC. PGE2 antagonized the effect of indomethacin on PC release. We conclude that PC release by isolated porcine gastric mucous cells is regulated in a manner different from type II pneumocytes. PC release is impaired by indomethacin and this impairment is restored by PGE2.
Butyrate enhances major histocompatibility complex class I, HLA‐DR and ICAM‐1 antigen expression on differentiated human intestinal epithelial cells
Authors: SIAVOSHIAN S. , BLOTTIÈRE H. M. , BENTOUIMOU N. , CHERBUT C. , GALMICHE J. P.
Published: November 2003

Besides its metabolic role, butyrate, a by‐product of colonic fermentation, can modulate colonocyte proliferation and the expression of various molecules. In inflammatory bowel diseases, epithelial cells express HLA class II molecules and may behave as antigen‐presenting cells. This study was performed to characterize the effect of butyrate on major histocompatibility complex expression by human colonocytes in comparison with interferon‐γ. Five cell lines displaying different differentiation features were analysed for antigen expression by flow cytofluorimetry. All lines expressed class I antigens, whereas only SW 1116 cells express HLA‐DR. On these cells, butyrate and interferon‐γ strongly enhanced HLA‐DR and ICAM‐1 expression, whereas a mild increase in class I antigens was noted. Moreover, an increase in class I antigens was observed on two other differentiated cell lines, and it was synergistic with interferon‐γ. Butyrate, by its modulation of HLA‐DR, ICAM‐1 and HLA class I expression, may act on antigen presentation and, thus, influence some inflammatory processes.
Adrenalitis and the adrenocortical response of resistant and susceptible mice to acute murine cytomegalovirus infection
Authors: PRICE P. , OLVER S. D. , SILICH M. , NADOR T. Z. , YERKOVICH S. , WILSON S. G.
Published: November 2003

Murine cytomegalovirus (MCMV) induces adrenalitis in BALB/c mice but does not compromise adrenal function, assessed by levels of circulating adrenocorticotropic hormone (ACTH) and by the response to challenge with synthetic ACTH. Levels of corticosterone increased 2 days after infection in mice of this strain, consistent with previously established interactions between mediators of acute inflammation and activation of the hypothalmus–pituitary–adrenal axis. Moreover, an adrenocortical response was critical to survival of BALB/c (but not C57BL/6) mice 3 days after infection, as pharmacologically or surgically adrenalectomized BALB/c mice died when given doses of virus up to fivefold lower than they could normally tolerate. However, death could not be prevented by the administration of soluble cytokine receptors to inhibit the action of interleukin 1 (IL‐1) or tumour necrosis factor alpha (TNFα). The corticosteroid response did not mediate MCMV‐induced thymic atrophy. As the above traits were all less evident in C57BL/6 mice, a common genetic basis is discussed.
Elevated serum transforming growth factor β1 level in primary lung cancer patients with finger clubbing
Authors: HIRAKATA Y. , KITAMURA S.
Published: November 2003

The mechanism causing finger clubbing in patients with lung cancer (LC) is still unclear. We compared age, cigarette consumption, data on blood gas analysis and pulmonary function tests among patients with LC with clubbing (n = 30) and without clubbing (n = 28) and among patients with pulmonary emphysema (PE) with (n = 11) and without clubbing (n = 17). We also examined serum concentrations of transforming growth factor β1 (TGFβ1) and insulin‐like growth factor‐I (IGF‐I) in the patients and healthy volunteers (n = 21). There were no differences in age or cigarette consumption. LC groups showed normal levels of PaO2 and PaCO2, suggesting that neither hypoxaemia nor hypercapnia caused clubbing in these patients. The level of serum TGFβ1 in patients with LC with clubbing was significantly higher than in other groups (P < 0.005), whereas levels of IGF‐I did not differ among the groups. Our data suggest that TGFβ1 may play a role in the mechanism of clubbing in patients with LC.
A method for the isolation and preparation of surfactant from tracheobronchial aspirates in infants and children for quantitative and pulsating bubble analysis
Authors: RAYMONDOS K. , MARTIN‐CARRERA I. , BERNHARD W. , POETS C. , VON DER HARDT H.
Published: November 2003

A method is presented for the investigation of surfactant function after isolation and preparation of pulmonary surfactant from tracheobronchial aspirates of mechanically ventilated infants and children. This method involved purification of surfactant from contaminating non‐surfactant phospholipids and mucus by sodium bromide density gradient centrifugation. The surfactant concentration in undiluted fluids (3.5±0.8mgmL−1; mean±SD) was calculated by extrapolating from the urea concentration in aspirates and serum. Phospholipid concentration was adjusted to approximately 3mgmL−1 and the surface activity was determined by means of a pulsating bubble surfactometer. Mean minimal and maximal tension values of all cycles were calculated after reaching steady state. Measurements obtained from surfactant isolated with this method showed a high reproducibility: the coefficient of variation for minimal surface tension was 6.1%. Therefore this method enables functional surfactant analysis in tracheobronchial aspirates.
Effects of vasopressin on human renal arteries
Authors: MEDINA P. , VILA J. M. , MARTINEZ M. C. , ALDASORO M. , CHUAN P. , LLUCH S.
Published: November 2003

The effects of vasopressin were studied in isolated rings from branches (2–3mm in external diameter) of human renal arteries obtained from 18 patients undergoing nephrectomy for non‐obstructive neoplasia. In arterial rings under resting tension, vasopressin produced concentration‐dependent and endothelium‐independent contractions with an EC50 of 9.1×10−10molL−1. The vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)AVP (10−6molL−1) displaced the control curve to vasopressin 564‐fold to the right in a parallel manner. In precontracted arterial rings and previously treated with the V1 antagonist (10−6molL−1) vasopressin caused endothelium‐independent relaxation. The relaxation to vasopressin was reduced significantly by indomethacin (10−6molL−1) and unaffected by the V1/V2 receptor antagonist desGly d(CH2)5‐d‐Tyr(Et)ValAVP (10−6molL−1) or by NG‐nitro‐l‐arginine methyl ester (10−4molL−1). These observations indicate that vasopressin is primarily a constrictor of human renal arteries by V1‐receptor stimulation. Vasopressin causes prostaglandin‐mediated dilatation of human renal arteries only if V1‐receptor blockade is present. The effects of vasopressin on human renal arteries may be relevant in those clinical situations characterized by increased plasma vasopressin levels.
Prospective cross‐over comparisons of three low‐density lipoprotein (LDL)‐apheresis methods in patients with familial hypercholesterolaemia
Authors: SCHAUMANN D. , WELCH‐WICHARY M. , VOSS A. , SCHMIDT H. , OLBRICHT C. J.
Published: November 2003

We prospectively compared effectiveness, selectivity and biocompatibility of three LDL‐apheresis methods, immunoadsorption (IMAL), dextran sulphate adsorption (DSAL) and heparin‐induced extracorporeal LDL precipitation (HELP). Seven patients with familial hypercholesterolaemia were treated twice with each method in random sequence. Reduction in atherogenic lipoproteins was without significant difference: LDL −60% to −75%, VLDL −20% to −30%, triglycerides −20% to −42%. High‐density lipoprotein (HDL)‐cholesterol was reduced by IMAL only (−27%, P<0.05); DSAL and HELP did not decrease HDL. Total plasma protein reduction was 13–15% with each method, indicating unselectivity. Albumin was significantly decreased by IMAL (−15%, P<0.05) but not by the other methods. DSAL and HELP reduced fibrinogen (−40%, −58%, P<0.0001) and other clotting factors. IMAL had almost no effect on coagulation. The white blood cell count did not change. C3 and C4 complement were decreased (−20% to −46%) by all methods. C5a complement did not increase in systemic blood, but was increased in the extracorporeal circulation of IMAL (+200%) and HELP (+150%). Plasma PMN elastase rose in all methods (+200%) indicating neutrophile degranulation. In conclusion, in this short‐term study of a small patient population, effectiveness of the three LDL‐apheresis methods was similar, but selectivity and biocompatibility were different. The therapeutic relevance of these differences for long‐term treatment remains to be elucidated.
Vasodilator responses to nitric oxide are enhanced in mesenteric arteries of portal hypertensive rats
Authors: HEINEMANN A. , STAUBER R. E.
Published: November 2003

Abstract. Nitric oxide (NO) is discussed as a mediator of the splanchnic hyperaemia in portal hypertension. We assessed the vasorelaxation by the NO‐dependent vasodilator acetylcholine, the NO donor 3‐morpholino‐sydnonimine (SIN‐1) and forskolin, a stimulator of the adenylate cyclase pathway in potassium‐preconstricted isolated perfused mesenteric arteries of portal vein‐ligated and sham‐operated rats. Dilator responses to acetylcholine and SIN‐1 were significantly enhanced in vessels of portal vein‐ligated rats as compared to sham‐operated rats, whereas no difference was found in forskolin‐induced vasodilatation. This suggests enhanced reactivity of the vasculature to NO in experimental portal hypertension.
Characterization of a soluble form of neutral endopeptidase‐24.11 (EC 3.4.24.11) in human serum: enhancement of its activity in serum of underground miners exposed to coal dust particles
Authors: SOLEILHAC J.‐M. , LAFUMA C. , PORCHER J.‐M. , AUBURTIN G. , ROQUES B. P.
Published: November 2003

A previous epidemiological study has reported the elevation of a serum metalloendopeptidase activity for underground coalminers exposed to chronic inhalation of coal mine dust particles. In this work, we have unambiguously characterized this activity as neutral endopeptidase (EC 3.4.24.11) using five different criteria. The apparent molecular weight of 100 000 g mol−1 calculated for the serum peptidase using Western blots or direct binding of the neutral endopeptidase 24.11 inhibitor [125I]‐RB104 to the enzyme in acrylamide gels, suggests that the soluble form of this ectoenzyme is not generated by a post‐translational cleavage of the membrane‐bound form, as is the case for the closely related ectoenzyme, angiotensin‐converting enzyme. The circulating endopeptidase very likely results from a shedding process. The increase in serum neutral endopeptidase 24.11 activity of underground miners compared with surface miners (5.7‐fold, P<0.01) is not correlated with systemic inflammation parameters, but seems to reflect the chronic pulmonary inflammatory state induced by coalmine dust exposure, and so may be a marker of lung injury.
Human and porcine smooth muscle cells share similar proliferation dependence on the mevalonate pathway: implication for in vivo interventions in the porcine model
Authors: MARTÍNEZ‐GONZÁLEZ J. , BADIMON LINA
Published: November 2003

Proliferation of smooth muscle cells (SMCs) plays an important role in vascular pathobiology by being involved in the development of coronary atherosclerosis and restenosis. Competitive inhibitors of 3‐hydroxy‐3‐methylglutaryl‐coenzyme A (HMG‐CoA) reductase have shown antiproliferative properties on different cell types. We have assessed the relative effectiveness of three HMG‐CoA reductase inhibitors (compactin, lovastatin and pravastatin) in blocking serum‐induced replication of human and porcine SMCs. No effects were seen on DNA synthesis in porcine or human SMCs at the reported therapeutic lipid‐lowering concentrations. The effectiveness of statins in blocking SMC proliferation was similar in both species; the IC50 values for porcine cells were 12.2μmolL−1, 12.6μmolL−1 and 1.16mmolL−1 for lovastatin, compactin and pravastatin respectively. Inhibition of SMC proliferation was reversed by addition of mevalonate but not by low‐density lipoprotein (LDL)‐cholesterol. Statins showed high antiproliferative efficiency against purified growth factors involved in human restenosis (1nmolL−1 platelet‐derived growth factor (PDGF), 1nmolL−1 epidermal growth factor (EGF), 10UmL−1α‐thrombin). The porcine model seems to be a suitable system, closely resembling the human model, for assaying in vivo new strategies, formulations and delivery systems targeted to the mevalonate pathway to inhibit local SMC response to percutaneous transluminal coronary angioplasty.
Biosynthesis of prostacyclin and thromboxane A2 during chronic hypoxaemia in children with cyanotic congenital heart disease
Authors: LEONHARDT A. , MAGSAAM J. , GOLDNER M. , KÜHL P. G. , SEYBERTH H. W.
Published: November 2003

The high risk of vaso‐occlusive events in children younger than 4 years with cyanotic congenital heart disease and polycythaemia has been attributed to increased thromboxane (Tx) A2 formation. In older children with cyanotic congenital heart disease, however, the risk of vaso‐occlusive events is much lower. We therefore hypothesized that the formation of TxA2 and prostacyclin is not disturbed in this age group. We measured urinary excretion of stable index metabolites of in vivo TxA2 and prostacyclin formation by gas chromatography–mass spectrometry in nine children (age 5.9–14.4, median 8.7 years) with cyanotic congenital heart disease, and in nine healthy, age‐matched control subjects. The patients excreted less 2,3‐dinor‐TxB2 (systemic TxA2 formation, P=0.03), 2,3‐dinor‐6‐keto‐PGF1α (systemic prostacyclin formation, P=0.03) and TxB2 (renal TxA2 formation, P=0.01) than the control subjects. We conclude that in children older than 5 years with cyanotic congenital heart disease, endogenous synthesis of TxA2 and prostacyclin is not stimulated. This result may explain the lower risk of vaso‐occlusive events in this age group as compared with younger children. In addition, our results suggest that chronic hypoxaemia may affect the in vivo formation of TxA2 and prostacyclin and the metabolic disposition of TxB2.