bluuebunny/crossref_metadata_2025 huggingface dataset:
Human parathyroid cell proliferation in response to calcium, NPS R‐467, calcitriol and phosphate
Authors: Roussanne M‐C. , Lieberherr M. , Souberbielle J. C. , Sarfati E. , Drüeke T. , Bourdeau A.
Published: March 2003

It remains uncertain how calcium, phosphate and calcitriol regulate parathyroid cell growth. The present study was aimed at examining possible direct effects of these modulators and of the calcimimetic NPS R‐467 on parathyroid cell growth in vitro.

Cell proliferation was determined by [3H]thymidine incorporation and cell cycle antigen Ki 67 expression in a parathyroid cell culture model derived from uraemic patients. The effect of NPS R‐467 on parathyroid hormone (PTH) secretion and intracellular [Ca2+]i response was also examined.

Increasing the [Ca2+] in the medium from 0·5 to 1·7 mM increased DNA synthesis (P < 0·005) and the number of Ki 67‐positive cells (P < 0·005). However, NPS R‐467 (0·01–1 µM) inhibited 3[H]thymidine incorporation by 35% in the presence of 0·5 mM [Ca2+]e. Exposure of cells to Ca2+ or NPS R‐467 led to a rapid increase of intracellular Ca2+, although the pattern of increase differed. Addition of calcitriol (10−10−10−7 M) to the culture medium suppressed [3H]thymidine incorporation dose‐dependently. Finally, high levels of phosphate (3·5 mM) in the medium led to a significant (P < 0·05) increase in [3H]thymidine incorporation.

The observed stimulatory effect of Ca2+ in the medium in vitro appears to be at variance with the inhibitory effect of calcimimetic NPS R‐467 in vitro. In an attempt to solve these apparent discrepancies, and based on the notion of a reduced calcium‐sensing receptor (CaR) expression in parathyroid tissues of uraemic patients, we hypothesize that Ca2+ may regulate parathyroid cell proliferation via two different pathways, with predominant growth inhibition in cases of high CaR expression or activation, but prevailing stimulation of proliferation in cases of low CaR expression.
Glutathione and α‐lipoate in diabetic rats: nerve function, blood flow and oxidative state
Authors: Van Dam P. S. , Van Asbeck B. S. , Van Oirschot J. F. L. M. , Biessels G. J. , Hamers F. P. T. , Marx J. J. M.
Published: March 2003

Background Increased oxidative stress is considered to be a causal factor in the development of diabetic complications, among which peripheral neuropathy. The pathophysiology of nerve dysfunction in diabetes has been explained both by reduced endoneurial microcirculation and alterations in endoneurial metabolism. It is unclear whether antioxidants primarily improve nerve blood flow or normalise systemic or endoneurial oxidative metabolism. Therefore, we evaluated the effects of the antioxidants glutathione and α‐lipoic acid on both nerve microcirculation and the antioxidative capacity and lipid peroxidation in experimentally diabetic rats.

Materials and Methods Streptozotocin‐diabetic rats were treated with different doses of α‐lipoic acid, reduced glutathione or placebo, and were compared with nondiabetic controls. We measured systemic and endoneurial antioxidants, malondialdehyde and whole blood hydrogen peroxide. Furthermore, we evaluated sciatic and tibial motor and sensory nerve conduction velocity, caudal nerve conduction velocity, and assessed sciatic nerve blood flow and vascular resistance by Laser‐Doppler flowmetry.

Results We observed a rise in erythrocyte glutathione by 27 % (P < 0·05), and a trend towards decreased plasma malondialdehyde in α‐lipoic acid, but not in glutathione‐treated animals in comparison with the placebo group. Simultaneously, sciatic nerve blood flow and vascular resistance were improved by daily α‐lipoic acid administration by 38% (P < 0·05). Peripheral nerve conduction velocity and endoneurial glutathione were not significantly influenced by antioxidant treatment.

Conclusions Only minor beneficial effects of α‐lipoic acid on nerve blood flow and oxidative state occur at the given doses; these effects were insufficient to improve nerve conduction deficits.
Characterization of platelet‐derived growth factor‐induced p38 mitogen‐activated protein kinase activation in vascular smooth muscle cells
Authors: Yamaguchi H. , Igarashi M. , Hirata A. , Tsuchiya H. , Susa S. , Tominaga M. , Daimon M. , Kato T.
Published: March 2003

Background The mitogen‐activated protein (MAP) kinase super‐family plays a crucial role in cell growth and differentiation and even in programmed cell death in response to diverse extracellular stimuli. The platelet‐derived growth factor (PDGF)‐BB is well known to promote the proliferation of vascular smooth muscle cells (VSMC) via extracellular‐regulated protein kinases (ERKs), leading to the development of cardiovascular diseases. However, it has not yet been clarified whether PDGFs that include other isoforms can activate the other parallel signal transduction pathways, c‐jun NH2‐terminal protein kinase (JNK) and p38 MAP kinase (p38), in VSMC. In this study, we investigated the effect of PDGFs on p38 activation in cultured rat VSMC.

Materials and methods After stimulation by PDGFs with SB‐203580 or PD‐98059, the cells were solubilized, and the expressions of MAP kinases, MAP kinase kinases (MKKs), phosphorylated DNA‐binding proteins, and cyclooxigenases (COXs) were examined by immunoblot analysis.

Results PDGFs activated p38 phosphorylation dose‐dependently, and the phosphorylations were specifically inhibited by SB‐203580 but not by PD‐98059. PDGFs also activated the phosphorylation of MKK 3/MKK 6 but not that of either stress‐activated protein kinase/ERK kinase or JNK. PDGFs affected the activation of a cyclic AMP response‐element binding protein, which was inhibited by SB‐203580. However, the activating transcription factor‐2 was not activated by PDGFs. Interestingly, the stimulation of PDGFs for 72 h enhanced the level of COX‐2, and these levels were decreased by SB‐203580.

Conclusion These results have clarified that PDGFs activate the p38 cascade via an MKK 3/6 pathway, independently of the ERK cascade, and subsequently regulate the level of COX‐2 in rat VSMC, providing that PDGFs influence the inflammatory process in the vascular wall.
Loop diuretics alter the diurnal rhythm of endogenous parathyroid hormone secretion. A randomized‐controlled study on the effects of loop‐ and thiazide‐diuretics on the diurnal rhythms of calcitropic hormones and biochemical bone markers in postmenopausal women
Authors: Rejnmark L. , Vestergaard P. , Heickendorff L. , Andreasen F. , Mosekilde L.
Published: March 2003

Background Thiazide diuretics (TD) reduce urinary calcium, bone loss and fracture risk. Loop diuretics (LD) may have opposite effects. These effects could depend on induced rhythmic changes in bone and calcium homeostasis.

Design After a run‐in period of 7 days, we studied (in a factorial design) the diurnal rhythms of plasma levels of calcium, phosphate, parathyroid hormone (PTH), 1,25‐dihydroxyvitamin D and osteocalcin, as well as renal excretions rates of calcium, phosphate, and cross‐linked N‐terminal telopeptide of type 1 collagen (NTx) in 50 postmenopausal women randomized to treatment with either a thiazide diuretic (TD; bendroflumethiazide, n = 14), a loop diuretic (LD; bumetanide, n = 13), LD plus TD (bendroflumethiazide plus bumetanide, n = 11), or placebo (n = 12).

Results In all four groups, all measured quantities showed a diurnal variation. LD caused a steep increase, with a subsequent decrease, in urinary calcium and plasma PTH. The mean 24 h plasma PTH concentration was increased (8·5 ± 0·9 mmol L−1) compared with placebo (4·4 ± 0·4 mmol L−1), whereas net 24 h renal calcium excretion did not differ from that of the placebo group due to a rebound hypocalciuria. Compared with placebo, diurnal rhythms of plasma phosphate and osteocalcin were changed with an increase during daytime and a decrease during the night. TD did not alter the diurnal rhythm of any of the measured quantities. However, the 24‐h renal calcium excretion decreased, whereas the mean 24‐h plasma calcium concentration increased without PTH suppression. LD plus TD caused changes similar to those observed with LD alone.

Conclusion One daily dose of LD increases parathyroid activity with alterations in the diurnal pattern of osteocalcin. This could indicate a potential anabolic effect of LD.
Serum chromogranin A as a screening test for gastric enterochromaffin‐like cell hyperplasia during acid‐suppressive therapy
Authors: Sanduleanu S. , De Bruïne A. , Stridsberg M. , Jonkers D. , Biemond I. , Hameeteman W. , Lundqvist G. , Stockbrügger R. W.
Published: March 2003

Background Serum chromogranin A (CgA), a marker of neuroendocrine neoplasia, increases during profound gastric acid inhibition, possibly reflecting the trophic effect of gastrin on the enterochromaffin‐like (ECL) cells.

Aims This study investigated the clinical value of serum CgA as a screening test for gastric fundic enterochromaffin‐like (ECL) cell hyperplasia during acid‐suppressive therapy.

Method A consecutive series of 230 dyspeptic patients referred for upper gastrointestinal endoscopy was investigated in a cross‐sectional design. They were 154 patients on continuous medium‐term (6 weeks to one year) or long‐term (longer than one year) acid inhibition with either proton pump inhibitors (PPIs, n = 117) or histamine2‐receptor antagonists (H2RAs, n = 37) for gastro‐oesophageal reflux disease, and 76 nontreated subjects, with normal endoscopic findings (control group). Fasting blood samples were analysed for gastrin and CgA. Gastric biopsy specimens (oxyntic mucosa) were examined for histological evaluation of gastritis (Sydney classification) and of ECL cell hyperplasia (Solcia classification).

Results Serum CgA levels correlated positively with serum gastrin, following a quadratic function (r = 0·78, P < 0·0001). Elevated serum CgA values during long‐term acid inhibition correlated with the presence and severity of fundic ECL cell hyperplasia. Multivariate analysis identified hypergastrinaemia (P < 0·0001), duration of acid inhibition (P < 0·0001), H. pylori infection (P = 0·008), ECL cell hyperplasia (P = 0·012), and body gland atrophy (P = 0·043) as independent predictors of elevated serum CgA. In subjects on long‐term acid inhibition (n = 123), serum CgA was equally sensitive but more specific than serum gastrin for the detection of ECL cell hyperplasia (sensitivity, 91·3% for both; specificity, 73% vs. 43%, P < 0·0001).

Conclusions During long‐term gastric acid inhibition, serum CgA levels reflect the presence and severity of fundic ECL cell hyperplasia. Serum CgA is therefore a useful screening test for gastric ECL cell proliferative changes within this context.
Interactions between major histocompatibility complex class II surface expression and HIV: implications for pathogenesis
Authors: Kamp W. , Breij E. C. W. , Nottet H. S. L. M. , Berk M. B.
Published: March 2003

Although it has been almost 20 years since the first cases of acquired immunodeficiency syndrome (AIDS) were documented, the pathogenesis is still not completely understood. Interactions between major histocompatibility complex (MHC) Class I and human immunodeficiency virus (HIV), resulting in down‐regulation of MHC‐I surface expression, have been reported to contribute to pathogenesis by suppressing the host's immune response. Interactions between MHC Class II and HIV have also been described, but it is unclear how these contribute to the pathogenesis. MHC‐II surface expression on HIV‐infected monocytes and monocytic cell lines has been described to be increased as well as decreased when compared to uninfected control monocytes. HIV‐specific mechanisms appear to down‐regulate MHC‐II expression on blood monocytes during HIV‐1 infection, whereas host mechanisms up‐regulate MHC‐II expression in response to infection of blood monocytes as well as brain macrophages. A balance between these two may determine MHC‐II expression levels in individual patients.

Altogether, HIV seems to be able to benefit from both low and high levels of MHC‐II surface expression. The first results in reduced immune surveillance of the host, allowing the virus to replicate faster; the second increases infectivity of the virus as a result of higher MHC‐II density on macrophages and virion particles.
Endogenous anti‐inflammatory response after coronary injury in a porcine model
Authors: Fantidis P. , Pérez de Prada T. , Fernández‐Ortiz A. , Sanmartín M. , Alfonso F. , Hernández R. , Escaned J. , Bañuelos C. , Sabaté M. , Macaya C.
Published: March 2003

Background Corticotropin‐releasing hormone (CRH)/adrenocorticotropic hormone (ACTH)/cortisol is the major anti‐inflammatory system. After percutaneous translumenal angioplasty, an inflammatory process is triggered. We investigate whether CRH/ACTH/cortisol axis is activated after deep vessel wall injury (DVWI).

Materials and methods Plasma and leukocyte CRH and ACTH, serum cortisol and IL‐1β, and leukocyte cAMP were measured (ELISA) in 16 pigs after anaesthesia (baseline), 60 min into anaesthesia without causing vascular injury and 90 min after DVWI of the left anterior descending (LAD) coronary artery induced by percutaneous directional atherectomy (Atherocath GTO 7F; DVI, Inc., Temecula, USA). Biochemical variables were also measured at baseline, 60 and 180 min into anaesthesia in six additional pigs without coronary intervention.

Results MANOVA showed that CRH/ACTH/Cortisol, cAMP and IL‐1β production was not modified during anaesthesia. Post‐DVWI plasma CRH (0·077 ± 0·046 ng mL−1), and cellular cAMP (0·14 ± 0·067 pmol 10−6 cells) increased significantly (P = 0·001) with respect to their baseline values (CRH = 0·036 ± 0·013 ng mL−1; cAMP = 0·081 ± 0·034 pmol 10−6). There was also a statistically significant increase (P = 0·02) in post‐DVWI IL‐1β (from 46·6 ± 12·8 to 64·05 ± 13·5 pg mL−1), and in serum cortisol (P = 0·05) compared to its baseline values (8·98 ± 3·2 µgr dL−1 vs. 6·57 ± 2·3 µgr dL−1, respectively).

Conclusion In our experimental model, coronary vessel wall injury‐activated CRH/ACTH/cortisol axis caused a significant increase in plasma CRH, cortisol and cellular cAMP levels, which may influence the response of coronary arteries to injury.
Polymorphisms in the TNF‐α and TNF‐receptor genes in patients with coronary artery disease
Authors: Allen R. A. , Lee E. M. , Roberts D. H. , Park B. K. , Pirmohamed M.
Published: March 2003

Background Coronary artery disease (CAD) is both multifactorial and polygenic in nature. Atheroma formation, the pathological hallmark of CAD, is an inflammatory process, with pro‐inflammatory cytokines, such as tumour necrosis factor‐α (TNF‐α), having a major role in its pathogenesis. We have therefore investigated whether polymorphisms in the TNF‐α (− 238 and − 308), TNF receptor 1 (position − 609 and + 10, intron 6) and TNF receptor 2 (position + 422, codon 198) genes show an association with CAD.

Materials and methods Patients with angiographically proven single vessel (n = 58) and multivessel (n = 122) CAD were compared to patients with angiographically proven normal coronary arteries (n = 79) and volunteers without clinical evidence of CAD (n = 250). Genotyping was performed by PCR‐RFLP analysis. For the TNF‐α polymorphisms, a meta‐analysis of all published studies was also undertaken.

Results No significant differences in allele or genotype frequencies were found between the normal coronary artery group or healthy volunteers and patients with CAD for any of the polymorphisms. There was also no difference in allele frequency between patients with single‐ and multivessel disease. For the − 308 and − 238 TNRα gene polymorphisms, a meta‐analysis of our data and previously published studies failed to demonstrate any significant association with CAD.

Conclusions Polymorphisms in the TNF‐α promoter region and TNF‐receptor genes are not associated with the development of CAD.
Renal proximal tubular cell growth and differentiation are differentially modulated by renotropic growth factors and tyrosine kinase inhibitors
Authors: Ernst F. , Hetzel S. , Stracke S. , Czock D. , Vargas G. , P. Lutz M. , Keller F. , Jehle P. M.
Published: March 2003

Background The renotropic growth factors (GFs), hepatocyte GF (HGF), epidermal GF (EGF), and insulin‐like GF‐I (IGF‐I) accelerate renal regeneration in animal models after toxic or ischemic injury. These GFs initiate their biological effects on renal tubular cells by interaction with specific transmembrane receptor tyrosine kinases.

Materials and methods In the proximal tubular cell line PT‐1, the biological effects of HGF, EGF, and IGF‐I and the growth‐inhibitory effects of different tyrosine kinase inhibitors (TKIs) were investigated. Receptor binding and tyrosine kinase phosphorylation were determined by ligand binding studies and Western blot analysis.

Results HGF, EGF, and IGF‐I bound with nanomolar affinity to their specific cell membrane receptor tyrosine kinases. In contrast to EGF or IGF‐I, HGF induced a variety of cell morphological changes, including cell scattering, formation of tubular structures, and expression of long microvilli on the apical cell membrane. HGF was a 10‐fold more potent and more effective growth promoter than EGF or IGF‐I. Among the TKIs tested, the mitogenic effect of HGF could be more specifically inhibited by emodin and tyrphostin, that of EGF by methyl‐2,5‐dihydroxycinnamate, lavendustin A, and genistein, and that of IGF‐I by geldanamycin.

Conclusions In contrast to EGF and IGF‐I, HGF stimulated both growth and differentiation of renal proximal tubular cells, demonstrating the amazing biological potency of this renotropic growth factor. Selective TKIs may be a promising approach to modulate diseases with abnormalities in protein kinase signalling pathways such as renal cell carcinoma.
PON1 L55M polymorphism is not a predictor of coronary atherosclerosis either alone or in combination with Q192R polymorphism in an Italian population
Authors: Arca M. , Ombres D. , Montali A. , Campagna F. , Mangieri E. , Tanzilli G. , Campa P. P. , Ricci G. , Verna R. , Pannitteri G.
Published: March 2003

Abstract Background  The present study evaluated the role of the PON1 L55M polymorphism independently and in conjunction with the Q192R polymorphism on the risk of coronary atherosclerosis in an Italian population.

Materials and methods  Three hundred and ninety‐one subjects with significant coronary stenosis (> 50%) (coronary artery disease‐positive; CAD+), 196 subjects with normal coronary arteries (< 10% stenosis) (CAD−) and 178 healthy controls were screened using a combination of polymerase chain reaction and restriction enzyme digestion.

Results  In the pooled population, the frequencies of L and M alleles were 0·63 and 0·37, respectively; the most common haplotypes were QQ/LM (24·2%) and QR/LL (21·8%) and a strong linkage disequilibrium between L/55 and R/192 alleles was observed (D′ = −0·91; P < 0·0001). CAD+ subjects did not show any significant differences in the distribution of PON1–55 genotypes as compared to CAD− subjects and population controls (χ2 = 1·5, P = 0·8). After controlling for other risk factors, the low‐concentration M allele was not associated with a significant change of CAD risk (OR 1·02; 95% CI 0·80–1·29; P = 0·87). Moreover, the L55M polymorphism did not show any interaction with other risk factors such as smoking, diabetes, hypertension, low levels of high‐density lipoprotein (HDL) or high ratios of low‐density to high‐density lipoproteins. The combination of L55M with the Q192R polymorphism did not show any effect on CAD risk. However, a marginal decrease in myocardial infarction risk was detected when QQ/MM carriers (OR 0·51; 95% CI 0·26–0·99; P = 0·048), but not LL/RR carriers, were compared with subjects not homozygous for an L or R allele.

Conclusions  These findings did not indicate a major effect of the PON1 L55M polymorphism, either alone or in combination with the Q192R polymorphism, on CAD risk. Additional studies are needed for a better evaluation of the role of the 55/192 PON1 genotypes in combination on myocardial infarction risk.
A small reduction in glomerular filtration is accompanied by insulin resistance in type I diabetes patients with diabetic nephrophathy
Authors: Svensson M. , Yu Z‐W. , Eriksson J. W.
Published: March 2003

Abstract Background Insulin sensitivity and insulin clearance are compromised in end‐stage renal disease but it has not been fully established whether they are altered in earlier stages of diabetic nephropathy.

Design We studied three groups of patients with type 1 diabetes; 10 with no sign of nephropathy, 11 with albuminuria (> 20 µg min−1) but normal glomerular filtration rate (GFR) and eight with a small reduction in GFR, (43–73 mL min−1 1·73 m−2). The groups were matched for age (range 36–61 years), body mass index (BMI), diabetes duration and glycaemic control. The euglycaemic hyperinsulinaemic clamp technique was utilized to study insulin sensitivity (M‐value) and metabolic clearance rate for insulin. Needle biopsies from abdominal subcutaneous fat tissue were obtained to study insulin binding, insulin degradation, insulin‐stimulated glucose uptake and anti‐lipolysis in adipocytes in vitro.

Results Patients with reduced GFR were more insulin‐resistant (M‐value 5·7 ± 0·7 mg kg LBM−1 min−1) than those without nephropathy (9·6 ± 0·7, P = 0·001) and those with only albuminuria (8·9 ± 1·2, P = 0·044). In all subjects taken together there was a strong association between insulin sensitivity and GFR (r = 0·46, P = 0·012). Patients with reduced GFR displayed no significant difference in insulin clearance (12·2 ± 1·6 mL kg−1 min−1) compared to controls (13·8 ± 1·3) but a slightly lower insulin clearance than patients with only albuminuria (16·6 ± 1·0, P = 0·027). There were no significant differences between patient groups in the adipocyte studies in vitro, i.e. with respect to insulin binding, insulin degradation and the effects of insulin on glucose uptake and lipolysis. This is compatible with humoral factors causing whole‐body insulin resistance and in the group with reduced GFR, we found that serum parathyroid hormone, interleukin‐6 and tumour necrosis factor‐α levels were elevated whereas the morning cortisol was decreased.

Conclusions In type 1 diabetes, the appearance of albuminuria does not seem to alter insulin sensitivity and clearance. A marked insulin resistance but no consistent impairment in insulin clearance seems to accompany progression to a stage with a slight reduction in GFR. These alterations are not accompanied by general defects in insulin target cells. Instead, alterations in the regulation of insulin‐antagonistic hormones and cytokines could potentially contribute to the development of insulin resistance in diabetic nephropathy.
Increased TGFβ1 plasma level in patients with lung cancer: potential mechanisms
Authors: Barthelemy‐Brichant N. , David J. L. , Bosquée L. , Bury T. , Seidel L. , Albert A. , Bartsch P. , Baugnet‐Mahieu L. , Deneufbourg J. M.
Published: March 2003

Background Plasma transforming growth factor β1 (TGFβ1) levels are elevated in patients with lung cancer. As TGFβ1 is mainly found in platelets and as nonmalignant pulmonary diseases (NMPD) are frequently associated with lung cancer, we investigated the potential contribution of platelet degranulation and/or of a concomitant NMPD to the increased plasma levels of TGFβ1 reported in patients with lung cancer.

Materials and Methods Blood samples were collected in duplicate from 30 healthy subjects, 14 patients suffering from NMPD and 37 patients with lung cancer. The platelet count was determined and the samples were processed to obtain plasma. One sample was collected in EDTA (EDTA plasma) and the other in a mixture inhibiting platelet degranulation (PIM plasma). TGFβ1 concentrations and β‐thromboglobulin (βTG) levels, an index of platelet degranulation, were measured in both plasma samples.

Results TGFβ1 and βTG plasma levels measured in PIM plasma were lower than those obtained in EDTA plasma. With respect to PIM plasma, both TGFβ1 and βTG levels were higher in patients with lung cancer than those with NMPD and in healthy individuals. In patients with NMPD, only TGFβ1 levels were increased as compared to healthy controls, βTG levels being similar.

Conclusion Methods for collecting and processing blood samples are critical in determining reliable circulating TGFβ1 levels. Increased TGFβ1 plasma levels observed in patients with lung cancer are related, at least partly, to concomitant NMPD and also to platelet degranulation as proved by increased βTG levels.
Endocrine abnormalities in healthy first‐degree relatives of type 2 diabetes patients – potential role of steroid hormones and leptin in the development of insulin resistance
Authors: Jansson P‐A. , Eliasson B. , Lindmark S. , Eriksson J. W.
Published: March 2003

Background First‐degree relatives of type 2 diabetes patients are at risk of developing diabetes and they display several metabolic and hormonal perturbations. The interplay between insulin resistance, steroid hormones and circulating leptin is, however, still not fully explored in this group.

Design Thirty‐three healthy first‐degree relatives of type 2 diabetic patients (relatives; M/F 19/14) were compared to 33 healthy subjects without a family history of diabetes (controls) and the groups were matched for gender, age and body mass index (BMI). We performed euglycaemic hyperinsulinaemic clamps and blood was sampled for hormone analyses.

Results Relatives exhibited decreased insulin sensitivity (index of metabolic clearance rate of glucose; MCRI) but when genders were analysed separately, this difference was significant only in males (11·3 ± 1·3 vs. 15·0 ± 1·5 units, means ± SEM, P = 0·030). In male relatives morning cortisol and testosterone levels were lower, whereas leptin was higher than in male controls (P = 0·018, 0·008 and 0·063, respectively). In male relatives plasma testosterone levels were significantly associated with insulin sensitivity (r = 0·48, P = 0·040). Circulating leptin levels were inversely correlated with insulin sensitivity in all subject groups (r‐values –0·49 to –0·66; P < 0·05, except in female control subjects P = 0·063). These associations were present also when age and BMI or waist : hip ratio were included in stepwise multiple regression analyses.

Conclusion Male subjects genetically predisposed for type 2 diabetes display several endocrine abnormalities including leptin, cortisol and testosterone levels. Dysregulation of these hormones may be important in the development of insulin resistance and type 2 diabetes.
Blood glucose pre‐prandial baseline decreases from morning to evening in type 2 diabetes: role of fasting blood glucose and influence on post‐prandial excursions
Authors: Trovati M. , Ponziani M. C. , Massucco P. , Anfossi G. , Mularoni E. M. , Burzacca S. , Tassone F. , Perna P. , Traversa M. , Cavalot F.
Published: March 2003

Background  To know the relationships between pre‐ and postprandial blood glucose (BG), i.e. BG profile shape, is a requisite for an appropriate therapy for type 2 diabetic patients. In non diabetic subjects, pre‐breakfast, pre‐lunch and pre‐dinner BG are similar, so that BG postprandial excursions are superimposed on a stable BG preprandial baseline. We aimed to clarify: (a) whether BG preprandial baseline is stable also in type 2 diabetes and (b) whether fasting BG (FBG) influences the slope of BG preprandial baseline and the relationships between pre‐ and postprandial BG.

Design  We evaluated self‐measured BG profiles of 237 type 2 diabetic patients on diet alone (M/F, 152/85; age 58·6 ± 0·7 years; years from diagnosis 4·8 ± 0·6; BMI 28·0 ± 0·3 kg m−2): 536 profiles containing preprandial BG (corresponding HbA1c 6·8 ± 0·06%) and 208 profiles containing both pre‐ and postprandial BG (corresponding HbA1c 6·8 ± 0·09%). The profiles, measured by nurses, of 866 type 2 diabetic patients on diet alone were also considered (corresponding HbA1c 6·7 ± 0·04%).

Results  In self‐measured profiles containing only preprandial BG: (i) FBG (6·77 ± 0·07 mmol L−1) is higher than pre‐lunch BG (6·09 ± 0·07 mmol L−1, P = 0·0001) and pre‐dinner BG (5·84 ± 0·06 mmol L−1, P = 0·0001); (ii) the delta value between FBG and predinner BG is correlated with FBG (r = 0·57, P = 0·0001), the highest FBG, the steepest the fall of BG preprandial baseline throughout the day. This trend is confirmed in profiles measured by nurses. In profiles containing both pre‐ and postprandial BG: (i) there is a trend to preprandial BG fall (P = 0·0001) and to postprandial BG increase (P = 0·0001) from morning to evening; (ii) postprandial excursions are influenced and sometimes masked by the slope of BG preprandial baseline, thus, in profiles with FBG ≤ 6·7 mmol L−1 all postprandial values are higher than FBG (P = 0·0001), whereas in profiles with FBG > 7·8 mmol L−1, postprandial values are not significantly higher than FBG.

Conclusion  In type 2 diabetes, the shape of BG profiles changes in relation to FBG, because it deeply influences the slope of BG preprandial baseline on which postprandial excursions are superimposed. Thus, before planning treatment policies, not only the extent of fasting and postprandial hyperglycaemia, but also the shape of profiles should be considered, to safely correct hyperglycaemia without inducing hypoglycaemia.
The effect of the Interleukin‐6–174G > C promoter gene polymorphism on endothelial function in healthy volunteers
Authors: Brull D. J. , Lesson C. P. M. , Montgomery H. E. , Mullen M. , DeDivitiis M. , Humphries S. E. , Deanfield J. E.
Published: March 2003

Aims  Atherosclerosis is a chronic inflammatory condition, manifest in its early stages by endothelial dysfunction. Interleukin‐6 (IL6) plays a key role in driving this process through stimulation of acute phase protein synthesis. We have examined the effect of the IL6 gene −174G > C promoter polymorphism on endothelial function in a group of healthy subjects.

Methods  248 adults aged 20–28 years participated. Polymerase chain reaction was performed for the −174G > C polymorphism. Brachial artery diameter was measured at rest and after forearm cuff occlusion by high‐resolution ultrasound. Responses were represented as absolute flow mediated dilatation (FMDA).

Results  Overall there was a trend towards greater FMDA for genotype CC, P = 0·14. No effect was seen in women; however, in men, following multivariate analysis, there was a significant association between genotype and FMDA, P = 0·04. In addition, a significant detrimental effect of smoking on FMDA was only seen in males of genotype CC (P < 0·05) when compared to nonsmokers of the same genotype.

Conclusion  IL6–174G > C promoter polymorphism influences endothelial function in healthy male subjects. The detrimental effect of smoking on endothelial function is most clearly seen in men of genotype –174 CC, suggesting a genotype‐specific interaction with smoking.
Elective coronary angioplasty with 60 s balloon inflation does not cause peroxidative injury
Authors: Cedro K. , Marczak E. , Czerwosz L. , Herbaczynska‐Cedro K. , Rużyllo W.
Published: March 2003

Background The aim of this study was to evaluate the ongoing controversial issue of whether ischemia/reperfusion during elective coronary angioplasty evokes myocardial peroxidative injury.

Design We measured indicators of free radical damage to lipids (free malondialdehyde) and proteins (sulphydryl groups) in coronary sinus blood in 19 patients with stable angina who were undergoing elective angioplasty for isolated stenosis of the proximal left anterior descending coronary artery. Ischemia induced by 60 s balloon inflations was confirmed by lactate washout into coronary sinus after deflation, with immediate and 1 min samples. Peroxidative injury was assessed from washout of (a) malondialdehyde measured directly by high performance liquid chromatography and (b) reduced sulphydryl groups, inverse marker of protein oxidative stress.

Results Mean lactate concentration immediately after each deflation increased by 120–150% of the initial value, confirming ischemia and showing that blood originated largely from the ischemic region. Lack of myocardial production of malondialdehyde was confirmed by (a) no arteriovenous differences in individual basal concentrations (aortic, range 0·33–12·03 nmol mL−1, mean 7·82; coronary sinus blood, range 0·52–15·82 nmol mL−1, mean 8·18), and (b) after deflations, mean concentrations were not significantly different from preocclusion value. There was no decrease in concentration of sulphydryl groups throughout angioplasty.

Conclusion Elective coronary angioplasty with 60 s balloon inflations is a safe procedure that does not induce peroxidative myocardial injury as assessed by methods used in the present study.
Tumour cell–dendritic cell fusion for cancer immunotherapy: comparison of therapeutic efficiency of polyethylen‐glycol versus electro‐fusion protocols
Authors: Lindner M. , Schirrmacher V.
Published: March 2003

Background  Fusion of tumour cells with dendritic cells (DC) is a powerful new technology to increase tumour vaccine immunogenicity. The aim of this study was to compare fusion protocols with syngenic DCs with respect to the efficiency of polyethylen‐glycol‐(PEG) and electric pulse‐mediated fusions for induction of protective anti‐tumour immune responses. As a model we chose a low immunogenic and metastatic murine mammary carcinoma cell line, which mimics clinically relevant tumour features.

Methods

FACS‐staining, chromium release assay, therapeutic immunization, adoptive transfer.

Results  We show that the parental line with low cell surface expression of MHC molecules as well as a lacZ transfectant becomes highly immunogenic upon fusion with DCs. This was true for PEG‐ as well as for electro‐fused cells. Immunization with products of DCs and tumour cells cocultivated for 16 h without the fusing agent PEG also caused induction of profound anti‐tumour immunity, while this was not the case when using parental tumour cells or their lacZ transfectants as vaccines. Immune protection against the parental tumour cells after vaccination with fused cells was long‐lasting and could be transferred via immune spleen cells into immuno‐incompetent nude (nu/nu) mice.

Conclusion  Fusion products of DA3hi mammary carcinoma cells and DCs produced by an electric pulse were similar to those produced by PEG fusion with regard to vaccine potency in prophylactic antitumour immunization assays in vivo. Therefore, both techniques seem to be promising for clinical application.
Morning cortisol production in coronary heart disease patients
Authors: Fantidis P. , Perez De Prada T. , Fernandez‐Ortiz A. , Carcia‐Touchard A. , Alfonso F. , Sabaté M. , Hernández R. , Escaned J. , Bauelos C. , Macaya C.
Published: March 2003

Background The circadian cycle of the endogenous anti‐inflammatory system (EAIS) is characterized by a morning increase in cortisol production. Circulating interleukin‐6 (IL‐6) activates the EAIS. A circadian variation in the onset of myocardial infarction, sudden death, stable angina (SA) and unstable angina (UA) has been reported. The aim of this study was to determine morning cortisol production in coronary heart disease (CHD) patients.

Materials and methods Serum cortisol and IL‐6 were measured in 129 patients with either SA (n = 65) or UA (n = 64) and 40 healthy volunteers. Blood samples were taken between 9 : 00 h and 12 : 00 h. The upper normal range of cortisol (25 µg dL−1) was used as a reference to classify patients.

Results Forty‐eight patients had elevated cortisol levels (ECL) (32·5 ± 5·4 µg dL−1), while 81 patients had normal cortisol levels (NCL) (15·7 ± 5·9 µg dL−1). In NCL patients, IL‐6 levels (26·6 pg mL−1, ranged from 0·2 to 183.7) were significantly higher (P < 0·004) than in ECL patients (9·70 pg mL−1, range 0·07–56·5). Forty‐eight patients with UA belonged to the NCL group of patients, while only 16 UA patients belonged to the ECL group (χ2 = 0·000). Thirty‐two patients with SA belonged to the ECL group, and 33 to the NCL group (χ2 = 0·08).

Conclusions Patients with ‘inappropriately’ normal morning cortisol production had high IL‐6 levels. ‘Inappropriately’ normal cortisol, detected in 75% of UA and 50% of SA patients, may be insufficient for limiting inflammation. These findings have novel clinical implications and suggest new therapeutic approaches in the treatment of these patients.
Physical training increases heart rate variability in healthy prepubertal children
Authors: Mandigout S. , Melin A. , Fauchier L. , N’Guyen L. D. , Courteix D. , Obert P.
Published: March 2003

Background The aim of the present study was to evaluate the effect of an endurance training program on heart rate variability (HRV) in prepubertal healthy children and to determine the relationships between HRV components and training‐induced cardiac adaptations.

Methods Nineteen prepubertal children (aged 10–11 years old) took part in this study: 12 children were assigned to participate in a 13‐week endurance training program (3 × 1 h week−1; intensity, > 80% HRmax) and 7 children served as a control group. Before and after the 13‐week study period, all the children were tested for maximal oxygen uptake (V O2max), HRV was measured by spectral and time domain analysis of 5 h night ECG recordings, and left ventricular (LV) cardiac morphology and function were assessed by means of Doppler‐Echocardiography.

Results V O2max increased significantly (+15·5% ± 12·1; P < 0·01) after the training program. All the frequency domain components (absolute values) increased after training except the low (LF) to high (HF) frequency ratio. Also, LF and HF did not change when expressed relative to total power. For the time domain components, only N–N intervals, the standard deviation of all N–N and the average of all 5 min standard deviations of N–N increased after training. Our training program induced also an increase in LV internal diameter and mass as well as an enhancement in early diastolic passive LV filling with a concomitant reduction in late diastolic active LV filling. These cardiac morphological and functional adaptations did not correlate however, with the autonomous nervous system modifications due to training.

Conclusion Our study shows that an endurance training program had a positive effect on aerobic potential, morphological and functional cardiac parameters and on nocturnal global HRV in healthy prepubertal children without inducing sympathetic and parasympathetic modifications.
Rate‐dependency of calcitonin secretion in response to increased plasma Ca2+
Authors: Wang W. , Lewin E. , Olgaard K.
Published: March 2003

Background  Calcitonin (CT) is a polypeptide hormone secreted from C‐cells of the thyroid gland in response to hypercalcemia. The physiological contribution of CT to calcium homeostasis has not been completely clarified. The present study therefore further characterized the sigmoidal relationship between plasma ionized calcium (P‐Ca2+) and CT in normal rats, and examined the possibility of rate‐dependency of CT secretion in response to changes in P‐Ca2+.

Design  Hypercalcaemia was induced by an infusion of calcium gluconate at rate of 4·5 × 10−2 mmol h−1rat−1i.v. (n = 8) and hypocalcaemia was induced by an EGTA infusion at a rate of 4·5 × 10−2 mmol h−1rat−1 (n = 7) in one protocol: the ‘slow’ protocol. In another protocol an increased rate of infusion of calcium gluconate or EGTA was used to induce a more rapid change in P‐Ca2+. Calcium gluconate was infused at a rate of 6·0 × 10−2 mmol h−1 rat−1 (n = 6) and EGTA infused at a rate of 7·5 × 10−2 mmol h−1rat−1 (n = 7): the ‘rapid’ protocol.

Results  The infusions of both the ‘slow’ and ‘rapid’ protocols resulted in linear changes in P‐Ca2+, but with significantly different slopes (P < 0·01). The Ca2+/CT curves of both protocols were represented by sigmoidal curves. The ‘rapid’ increase of P‐Ca2+ resulted in a higher maximal CT secretion (2032 ± 215 pg mL−1) than the ‘slow’ increase of P‐Ca2+ (1213 ± 85 pg mL−1; P < 0·001), despite similar minimal and maximal levels being obtained in P‐Ca2+ in the two protocols. Thus, a significantly greater CT response was obtained with a more rapid increment in P‐Ca2+.

Conclusion  The relationship between P‐Ca2+ and CT is represented by a sigmoidal curve, as previously shown. The CT response depended, however, not only upon the concentration of P‐Ca2+ obtained but also upon the rate of increase in P‐Ca2+, demonstrating rate‐dependency as another significant physiological relation between Ca2+ and CT.
Current and adolescent levels of cardiopulmonary fitness are related to large artery properties at age 36: the Amsterdam Growth and Health Longitudinal Study
Authors: Ferreira I. , Twisk J. W. R. , Van Mechelen W. , Kemper H. C. G. , Stehouwer C. D. A.
Published: March 2003

Background High levels of cardiopulmonary fitness (VO2max) are associated with reduced risk of cardiovascular morbidity and mortality, but little is known to what extent this is related to the effects of cardiopulmonary fitness on atherosclerosis and arterial stiffness. Moreover, the time course of these relationships needs to be elucidated. We sought to investigate (i) the cross‐sectional relationship between VO2max and carotid atherosclerosis and carotid and femoral arterial stiffness at age 36, as well as (ii) the relationship between VO2max during adolescence (13–16 years) and the same arterial properties at age 36 (prospective analyses).

Design Cross‐sectional analyses consisted of 351 subjects (183 women) and the prospective analyses of a subpopulation of 154 subjects (79 girls). Arterial properties were assessed noninvasively by ultrasound imaging; VO2max was measured with a maximal running text on a treadmill with direct measurements of oxygen uptake.

Results After adjustment for confounding by other known risk factors, current and adolescent levels of VO2max were independently associated with carotid intima‐media thickness (β = −0·288, P = 0·004 and β = −0·381, P = 0·012) in men, and with the diameter of the femoral artery (β = 0·375, P < 0·001 and β = 0·252, P = 0·026, respectively) in both sexes. Current levels of VO2max were positively associated with the compliance of the carotid and the femoral arteries (β = 0·186, P = 0·023 and β = 0·183, P = 0·033, respectively), and with the distensibility of the carotid (β = 0·162, P = 0·047) but not the femoral artery.

Conclusion We conclude that cardiopulmonary fitness is associated with large artery properties at age 36, and that the roots of this association may already be present in adolescence.
The hormone‐sensitive lipase i6 gene polymorphism and body fat accumulation
Authors: Lavebratt C. , Rydén M. , Schalling M. , Sengul S. , Ahlberg S. , Hoffstedt J.
Published: March 2003

Background The hormone sensitive lipase (HSL) catalyses the breakdown of adipose tissue triglycerides into free fatty acids. The objective of this study was to determine whether HSLi6 microsatellite allele 5 (A5) and/or homozygosity for this allele is associated with body fat in Swedes.

Design A large case–control study on gender‐specific association for several body fat‐related clinical parameters to HSLi6 A5, and to HSLi6 A5 homozygosity, comparing A5 with the other alleles in group. The subjects were 323 obese patients (85 males, 238 females) without other metabolic complication, and 301 nonobese healthy individuals (134 males, 167 females). They were analyzed for various body fat‐related clinical parameters, and HSLi6 genotype.

Results Homozygosity for HSLi6 A5 was a risk factor for obesity, BMI ≥ 30 kg m−2 (Odds ratio = 1·75, 95% CI 1·58–1·93) and body fat mass > 39·6% (Odds ratio = 1·89, 95% CI 1·60–2·23) in women. This genotype was also associated with increased diastolic blood pressure and triglyceride level among nonobese women, and with increased body fat mass and waist/hip ratio among nonobese men.

Conclusion HSLi6 A5 homozygosity is a risk factor for body fat accumulation.
Plasma vitamin E, total antioxidant status and vascular function in young adults
Authors: Leeson C. P. M. , Mann A. , Kattenhorn M. , Deanfield J. E. , Lucas A. , Muller D. P. R.
Published: March 2003

Background Epidemiological studies have reported an inverse relationship between vitamin E status and coronary heart disease. This relationship has not, however, been confirmed by the majority of intervention studies, which have been carried out relatively late in the disease process. The protective effects of vitamin E may be more important earlier in life, before vascular changes have become established. This study investigated whether dietary vitamin E could prevent preclinical arterial changes in young adults relevant to the development of cardiovascular disease.

Materials and methods Measures of vascular function (arterial distensibility and endothelial‐dependent and ‐independent vascular responses) were assessed by noninvasive high resolution ultrasound and related to plasma vitamin E and total antioxidant concentrations in 326 adults, aged 20–28 years.

Results Neither vitamin E (alone or adjusted for lipids) nor total antioxidant status were significantly related to vascular endothelial function or arterial distensibility in either sex. There was no threshold level of vitamin E above which vascular function improved and neither vitamin E nor total antioxidant status interacted with any risk factor, such as smoking or increased low‐density lipoprotein concentrations.

Conclusions Neither plasma vitamin E concentrations nor total antioxidant status achieved by dietary intake during young adulthood were related to vascular endothelial function or arterial distensibility.
Clinical and genetic features underlying the response of patients with bronchial asthma to treatment with a leukotriene receptor antagonist
Authors: Mastalerz L. , Nizankowska E. , Sanak M. , Mejza F. , Pierzchalska M. , Bazan‐Socha S. , Bestynska‐Krypel A. , Cmiel A. , Szczeklik A.
Published: March 2003

Background Treatment with antileukotriene drugs results in clinical improvement in many, though not all, patients with asthma. It can be hypothesized that the subpopulation of asthmatic patients, characterized by aspirin intolerance and cysteinyl‐leukotriene overproduction, might profit most from antileukotriene treatment.

Materials and methods We compared the clinical response to montelukast in two well‐matched groups of patients with mild asthma: 26 aspirin‐intolerant asthmatics (AIAs) and 33 aspirin‐tolerant asthmatics (ATAs). We also searched for possible predictors of the clinical response among the parameters reflecting the expression and production of cysteinyl‐leukotrienes (cys‐LTs). This was an 8‐week, single‐blind, placebo‐controlled trial.

Results Following a 3‐week montelukast 10 mg day−1 treatment compared with placebo, there was a statistically significant reduction in the mean daytime and nocturnal asthma symptoms and β2‐agonist use, as well as a significant improvement in the morning and evening peak expiratory flows and quality of life. Both groups showed a similar significant improvement in the parameters studied. Clinical response did not correlate with the baseline urinary LTE4 excretion level. Improvement of asthma was observed mostly in patients with a low baseline and non‐IL‐5 inducible expression of LTC4 synthase (LTC4S) mRNA in eosinophils. There was a trend toward a better response in carriers of LTC4S allele C, but no relationship to the CC10 genetic polymorphism.

Conclusions No difference in the clinical response to the montelukast treatment was observed between the AIAs and the ATAs.