bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of platelet density and volume measurements to estimate the severity of pre‐eclampsia
Authors: Järemo P. , Lindahl T. L. , Lennmarken C. , Forsgren H.
Published: March 2003

This study evaluated whether it is possible to estimate the severity of pre‐eclampsia through in vitro measurements of platelet and granulocyte parameters.

Eighteen pre‐eclamptic women in the third‐trimester of pregnancy and 11 women in the third‐trimester of normal pregnancies were included in the study. Three to 12 months after delivery, 15 patients with pre‐eclampsia and all the subjects with normal pregnancies were re‐examined. Before delivery, peak platelet density was determined using a specially designed apparatus. Before and 3–12 months after delivery the following were measured: platelet counts, mean platelet volume and neutrophil and monocyte counts. Furthermore, circulating P‐selectin, interleukin‐6 and myeloperoxidase were determined to estimate platelet, monocyte and granulocyte activities, respectively.

Compared to their results after delivery, pre‐eclamptic females demonstrated lower platelet counts (P < 0·001) and raised mean platelet volumes (P < 0·01). Both pre‐eclamptic women (P < 0·01) and normal pregnancies (P < 0·05) demonstrated elevated soluble P‐selectin at pregnancy. Then pre‐eclamptic women had advanced neutrophil counts (P < 0·01) but normal pregnancies showed a similar phenomenon (P < 0·001). Interleukin‐6 remained normal during pregnancy. Plasma myeloperoxidase levels were lower both in pre‐eclampsia (P < 0·05) and in normal pregnancies (P < 0·001). In pre‐eclampsia elevated blood pressure was related to higher mean platelet volumes (P < 0·05). Furthermore, a group of pre‐eclamptic females whose platelets had disturbed density distribution displayed elevated mean platelet volumes (P < 0·01).

The present work demonstrates considerable platelet alterations in pre‐eclampsia. We failed to show granulocyte involvement in the pathogenesis of the disease. Severe pre‐eclampsia is related to elevated mean platelet volumes. The latter parameter is associated with disturbed density distribution. It appears possible to estimate disease severity from measurements of platelet density and volume.
11β‐Hydroxysteroid‐dehydrogenase isoforms: tissue distribution and implications for clinical medicine
Authors: Diederich S. , Quinkler M. , Burkhardt P. , Großmann C. , Bähr V. , Oelkers W.
Published: March 2003

11β‐hydroxylation is essential for glucocorticoid and mineralocorticoid activity of a steroid. The enzyme catalyzing this reaction is termed 11β‐hydroxysteroid‐dehydrogenase (11β‐HSD). Two isoenzymes of 11β‐HSD have been characterized in human tissues. Whereas 11β‐HSD‐I works mainly as a reductase, 11β‐HSD‐II only functions as an oxidizing (inactivating) enzyme for physiological glucocorticoids. Thus, the tissue distribution of both enzymes plays a crucial role for the specific glucocorticoid status of an organ. This review summarizes our knowledge of tissue distribution of both 11β‐HSD isoenzymes, their physiological function and pathophysiological role in certain clinical abnormalities, and their relevance to the metabolism of synthetic glucocorticoid and mineralocorticoid compounds.
Nongenomically initiated steroid actions
Authors: Falkenstein E. , Wehling M.
Published: March 2003

The classical theory of steroid hormone action comprises binding to an intracellular receptor followed by modulation of transcriptional and translational events. These cumbersome model explains the characteristic latency of these genomic steroid effects. Over the past two decades, increasing evidence for rapid nongenomic effects of steroids, incompatible with the traditional model, has accumulated. These alternative steroid effects have been described for all classes of steroids and a multitude of species and tissues with different mechanisms of action.
How hydrocortisone substitution influences the quality of life and the bone metabolism of patients with secondary hypocortisolism
Authors: Wichers M. , Springer W. , Bidlingmaier F. , Klingmüller D.
Published: March 2003

Background

Even in the setting of chronic glucocorticoid substitution in hypocortisolaemic patients, severe side‐effects will eventually occur when the dosage is inappropriately high. This study evaluates the effect of usual hydrocortisone substitution dosages on the well‐being of the patients and on parameters of the bone metabolism to establish an optimum substitution dosage.

Design

In a double blind study nine patients with secondary hypocortisolism, being divided in three groups of three, received different doages of hydrocortisone (15, 20, 30 mg per day). Well‐being was assessed using three different, validated questionnaires. Markers of bone metabolism were measured in blood and urine.

Results

The patients' quality of life was not impaired even at low dosages of hydrocortisone (15 or 20 mg per day). Of all laboratory parameters only osteocalcin significantly changed, decreasing at higher dosages.

Conclusions

Our study shows that a risk of bone loss may be avoided with a substitution dosage of 20 mg or even 15 mg hydrocortisone per day, without influencing the well‐being of the patient.
Metabolism of glucocorticoids and mineralocorticoids in patients with adrenal incidentalomas
Authors: Maser‐Gluth C. , Reincke M. , Allolio B. , Schulze E.
Published: March 2003

Background

Adrenal incidentalomas are mostly nonfunctioning adrenocortical adenomas (NFI). However, in 5%–12% of the patients a preclinical Cushing's syndrome (PCS) with autonomous cortisol production by the tumour is present. Since urinary free cortisol excretion is not sensitive enough to determine subclinical hypercortisolism, in the present study more sensitive indicators of daily cortisol production were measured.

Design

(1) Tetrahydrocortisol, tetrahydrocortisone, urinary free cortisone together with urinary free cortisol were measured in 35 patients with adrenal incidentalomas (29 NFI and six PCS) and in 35 healthy controls. (2) Since little is known about daily aldosterone production, aldosterone metabolite excretions were measured. (3) As recently reported, ACTH stimulation revealed an increased response of precursors of the glucocorticoid and mineralocorticoid pathway. To find out which steroidogenic enzymes have altered activities, a 1–24ACTH stimulation test (250 μg i.v.) was carried out in 25 patients and 18 healthy controls with determination of multiple steroids. (4) Finally, since it was assumed that 21‐hydroxylase deficiency or even 11b‐hydroxylase deficiency may be involved in adrenal tumourigenesis, the prevalence of germline CYP21B and CYP11B1 mutations were studied in the same patients, who had underwent the ACTH stimulation test.

Results

(1) Glucocorticoid metabolites were within the normal range in all but three patients with NFI. As a group, the patients had subtle alterations in cortisol metabolism. Tetrahydrocortisol excretion was elevated in NFI and PCS compared with normal subjects (2á1 ± 0á2 and 2á5 ± 0á5 vs. 1á5 ± 0á1 mg 24 h−1; P < 0á05). Accordingly, the twofold elevation of the tetrahydrocortisol/free cortisol ratio indicates an increased 5β‐reduction of cortisol in the liver. (2) Tetrahydroaldosterone and aldosterone‐18‐glucuronide excretions were not different to controls. (3) In patients with incidentalomas an increased response to ACTH was seen for 17‐hydroxyprogesterone (595 ± 133 vs. 160 ± 25 ng dL−1), 21‐desoxycortisol (105 ± 25 vs. 29 ± 9 ng dL−1) and 11‐desoxycortisol (401 ± 40 vs. 293 ± 17 ng dL−1). (4) In only one of 25 patients, a heterozygous deletion in exon 3 of the CYP21B gene was detected.

Conclusions

(1) In conclusion, even the excretion of the main glucocorticoid metabolites is not a marker sensitive enough to distinguish between NFI and PCS. However, it is also possible that alterations in cortisol secretion are qualitative rather than quantitative. (2) Zona glomerulosa function is not influenced. (3) The elevation of 21‐desoxycortisol argues against an impairment of 11β‐hydroxylase and favours a decreased activity of 21‐hydroxylase. All others had wild‐type sequences of both genes. (4) In conclusion, neither 21‐hydroxylase deficiency nor 11β‐hydroxylase deficiency are predisposing factors for adrenal tumourigenesis.
Pro‐inflammatory cytokines in patients with essential hypertension
Authors: Peeters A. C. T. M. , Netea M. G. , Janssen M. C. H. , Kullberg B. J. , Van der Meer J. W. M. , Thien T.
Published: March 2003

Background

It has been suggested that abnormalities in the immune response play a role in the pathogenesis of essential hypertension (EH). The aim of this study was to assess circulating concentrations and ex vivo production of the pro‐inflammatory cytokines tumour necrosis factor‐α(TNF‐α) and interleukin‐1β (IL‐1β), and of the anti‐inflammatory cytokines IL‐1 receptor antagonist (IL‐1ra) and IL‐6 , in patients with EH and compare them with healthy volunteers.

Patients and methods

Plasma cytokine concentrations were measured in EH patients and control volunteers by specific radioimmunoassays and ELISA. Ex vivo cytokine production was assessed after stimulation of whole‐blood with lipopolysaccharide.

Results

Circulating concentrations of TNF, IL‐1 and IL‐6 did not differ between EH patients and controls. In contrast, IL‐1ra circulating levels were higher in EH patients. Hypertensive patients had an increased IL‐1 and IL‐6 production capacity when whole blood was stimulated ex vivo with lipopolysaccharide, while TNF production was lower. IL‐1ra production capacity did not differ between patients and controls.

Conclusions

Patients with EH have an altered profile of pro‐and anti‐inflammatory cytokines, consistent with monocyte activation in the circulation. The importance of these changes for the pathogenesis of EH and/or its secondary complications remains to be elucidated.
The alpha‐amino group of l‐arginine mediates its antioxidant effect
Authors: Wallner S. , Hermetter A. , Mayer B. , Wascher T. C.
Published: March 2003

Antioxidant effects may constitute part of the possible antiatherogenic effects of the amino acid l‐arginine. These antioxidant properties were further characterized in a model of lipoprotein oxidation.

Oxidation of lipoproteins in unfractionated human serum was continuously monitored by a fluorescent probe. The antioxidant effects of l‐arginine, N‐α‐acetyl‐arginine and vitamin E in combination with l‐arginine were measured after initiation of free radical generation with either copper or 2,2′‐azobis(2‐amidinopropane) hydrochloride (AAPH). The half‐time of the fast propagation rate for copper‐induced lipoprotein oxidation increased after incubation with l‐arginine in a dose‐dependent manner (P < 0·01). N‐α‐acetyl‐arginine did not show such effects. Vitamin E and l‐arginine show different effects on copper‐induced oxidation, the former increasing only lag‐time, the latter increasing only propagation rate, and do not have reciprocal effects. In contrast to copper‐induced oxidation, l‐arginine increased the lag‐time of AAPH‐induced lipoprotein oxidation (P < 0·01), with no effect on the propagation rate at physiological concentrations. Again, N‐α‐acetyl‐arginine did not show any antioxidant effects.

Our experiments provide further evidence that mechanisms other than serving as a substrate for the NO‐synthase could be involved in the antiatherosclerotic effect of l‐arginine. In addition, our experiments clearly show, that the antioxidant effect of l‐arginine is due to a chemical moiety different from that serving as the substrate for NO biosynthesis.
Effect of N‐acetylcysteine treatment on NO2‐impaired type II pneumocyte surfactant metabolism
Authors: Müller B. , Oske M. , Hochscheid R. , Seifart C. , Barth P. J. , Garn H. , Von Wichert P.
Published: March 2003

Inhalation of nitrogen dioxide (NO2) is known to alter the composition of the bronchoalveolar lavage (BAL) and to impair the surfactant metabolism of type II pneumocytes. However, information is sparse as to whether application of the widely used antioxidant N‐acetylcysteine (NAC) is capable of preventing or reducing these alterations. The aim of the study was to investigate if in vivo administration of NAC to NO2‐inhaling rats protected BAL parameters and physiology of type II pneumocytes from impairment.

For this purpose, rats were exposed to 720 p.p.m. h−1 NO2, that was applied continuously, intermittently or repeatedly. During inhalation one group of rats received saline and the other group received NAC antioxidant (200 mg kg−1, intraperitoneally) once a day.

The BAL protein and phospholipid content increased most in the continuously and repeatedly NO2‐exposed rats when compared to the controls, while the intermittent exposure did not change these parameters. Application of NAC led to a marked decrease of the protein elevation for the continuously and intermittently exposed groups, but exhibited no influence on the BAL phospholipid. Surprisingly, all NO2 exposure modes elevated the glutathione content (reduced and oxidized) in the BAL. Application of NAC clearly decreased the content of both forms of glutathione in the continuously and the repeatedly NO2‐exposed groups. Phospholipid synthesis, measured by choline uptake into type II cells, was increased most after continuous NO2 inhalation. The NAC reduced this increase moderately. Whereas choline uptake by type II cells was obviously stimulated by NO2, the stimulated secretion of phosphatidylcholine from these cells was decreased by this oxidant. Only continuous exposure reduced this activity markedly. The NAC clearly restored the impaired secretion activity in the cells from the continuously NO2‐exposed animals.

Since the efficacy of NAC in the prevention of NO2‐induced impairments in the surfactant system is striking mainly in the continuously exposed group, we suggest that administration of NAC to NO2‐induced lung injury partially restores altered BAL components and the impaired physiology of type II pneumocytes.
Effects of bile salts and aliphatic ionic surfactants on human lymphocyte proliferation
Authors: Podevin P. , Correia L. , Montet J C. , Conti F. , Chéreau C. , Calmus Y. , Poupon R.
Published: March 2003

Background The molecular mechanisms involved in the immunosuppressive properties of bile salts are partly unknown.

Methods The aim of the study was to compare the effects of bile salts to those of various compounds with a steroid structure, or straight‐chain hydrocarbons of different lengths and polar groups in the human mixed lymphocyte reaction.

Results We showed a significant correlation between the effects of bile salts and a low critical micellar concentration, a high surface activity index, and the absence of conjugation. In addition to mixed lymphocyte reaction (MLR) inhibition, chenodeoxycholate (CDC) inhibit ConA‐induced IL2 production without any effect on IL2 R expression. Fusidate, a negatively charged steroid, with physical properties comparable to those of deoxycholate, had similar effects. Cetyltrimethylammonium bromide (CTAB), which exhibited a very low critical micellar concentration, inhibited mixed lymphocyte reaction in an extent comparable to cyclosporin A. In contrast, aliphatic compounds with critical micellar concentrations in the same range as bile salts but with a lower molecular area had no effect.

Conclusion Amphiphilic negatively charged molecules inhibit T‐cell proliferation to an extent that is dependent upon their hydrophobicity. These results may be explained, at least in part, by a modification in the cell membrane lipid bilayer structure.
Suppression of superantigen‐induced lung injury and vasculitis by preadministration of human urinary trypsin inhibitor
Authors: Onai H. , Kudo S.
Published: March 2003

We examined whether the lung injury produced in rats by intraperitoneal injection of the superantigen, staphylococcal enterotoxin B (SEB), could be inhibited by intravenous preadministration of human urinary trypsin inhibitor (UTI), which exhibits multipotent inhibitory effects on serine proteinases such as plasmin, chymotrypsin, or human leukocyte elastase or cathepsin G, since preliminary experiments showed the ability of UTI to bind lipopolysaccharides and bacterial toxins.

For ligand blotting analysis, four kinds of toxins were run on a slab gel and the binding of UTI to the toxins was visualized by immunoblotting. Lung tissue from 26 rats was used for immunohistochemistry using a mouse antirat CD 45 mAb and an antirat macrophage mAb. Lung tissue from 31 rats was used for measurement of myeloperoxidase activity before and after intraperitoneal injection of SEB, after infusion of PBS, UTI, PBS‐SEB or UTI‐SEB combination. Ten of the 26 rats described above were used for electron microscopy. Rat sera were used for measurement of TNF‐α. Statistical analysis was performed using the Mann–Whitney U‐test.

Intraperitoneal injection of SEB caused an increase in the number of punctate areas of haemorrhage on the surface of the lung with time, and histological examination revealed lung injuries with different extents, vasculitis where inflammatory cells were concentrated, and infiltration of numbers of eosinophils into the alveolar septa. However, preadministration of UTI for rats markedly attenuated lung injury and vasculitis induced by intraperitoneal injection of SEB. This revealed, from a marked reduction in the number of inflammatory cells and the extent of injury, a marked inhibition of serum TNF‐α production and reduction of myeloperoxidase content of rat lungs compared to controls.

UTI may have defensive effects to infection by suppressing the early responses of stimulated cells to activated stimulus such as SEB as well as the release of stimulant‐mediated cytokines via trapping of bacterial toxins.
Anabolic effects of rhIGF‐I/IGFBP‐3 in vivo are influenced by thyroid status
Authors: Svanberg E. , Healey J. , Mascarenhas D.
Published: March 2003

Background There are close interrelationships between hormones that regulate bone formation and protein biosynthesis. For example, growth hormone and thyroid hormones can influence plasma levels of insulin‐like growth factor‐I (IGF‐I). A patient's status regarding hormones other than IGF‐I may thus indirectly modify the efficacy of IGF‐I treatment. The aim of the current study was to determine if a statistical method could be used to identify key endocrine variables controlling an individual's response to IGF‐I treatment.

Design Biochemical profiles from the somatotropic, thyroid and adrenal axes were determined on two separate occasions in two different study cohorts. Each cohort was divided into four groups: placebo, low, medium and high dose of recombinant human IGF‐I/IGF binding protein‐3 (rhIGF‐I/IGFBP‐3). The relative changes in collagen C‐terminal peptide (CICP) levels were explained as a function of the basal endocrine profile of each treated individual. This relationship was further examined in an experimental rat model, where undernourished rats were rendered hypothyroid by propylthiouracil and subsequently treated with rhIGF‐I/IGFBP‐3.

Results The results of our statistical analysis in both cohorts indicated that each subject's response to rhIGF‐I/IGFBP‐3 administration was controlled in part by the individual's thyroid status prior to drug administration (r = 0·78 for both cohorts). The results from the animal study revealed that IGF‐I treatment stimulated muscle protein synthesis by 35 ± 9% (P = 0·05) in euthyroid rats but not in hypothyroid rats.

Conclusion The relationship between endocrine axes is not simple. An improved understanding of the interactions between neuroendocrine systems may facilitate the design of efficient drug regimens in the treatment of diseases such as osteoporosis and muscle wasting.
Myocardial gene expression of leukaemia inhibitory factor, interleukin‐6 and glycoprotein 130 in end‐stage human heart failure
Authors: Eiken H. G. , Øie E. , Damås J. K. , Yndestad A. , Bjerkeli V. , Aass H. , Simonsen S. , Geiran O. R. , Tønnessen T. , Christensen G. , Frøland S. S. , Gullestad L. , Attramadal H. , Aukrust P.
Published: March 2003

Background Studies in different animal models and plasma analyses in humans suggest that members of the interleukin‐6 (IL‐6) cytokine family may be involved in the pathogenesis of congestive heart failure (CHF). Accordingly, we have examined IL‐6‐related cytokines in chronic CHF in humans by analysing gene and protein expression in myocardium derived from patients with end‐stage heart failure and donor hearts.

Methods Gene expression of cytokines/receptors of the IL‐6 family was documented in myocardial samples using cDNA array hybridization and RNase protection assays. Immunohistochemistry was used to detect leukaemia inhibitory factor (LIF), IL‐6 and glycoprotein 130 (gp130) in myocardial tissues.

Results Myocardial gene activity was documented for the majority of IL‐6 family cytokines and their receptors. Immunohistochemical analysis localized IL‐6, LIF and their common receptor subunit gp130 to myocytes and vascular smooth muscle cells. LIF mRNA levels were enhanced in the left ventricles of CHF patients relative to the left ventricles of donor hearts (patients 4·6 ± 4·7 vs. donors 0·3 ± 0·3, P < 0·005). Myocardial IL‐6 and gp130 mRNA levels were not statistically different between patients and donors, but in contrast to LIF mRNA expression in heart explants, gp130 mRNA levels were significantly higher in left atrium compared with left ventricle in both patients and donors.

Conclusions Both mRNA and proteins of gp130 and its ligands IL‐6 and LIF are expressed in both nonfailing and failing human myocardium. The elevated LIF mRNA levels in left ventricles from patients with end‐stage heart failure suggest a role for LIF in the pathogenesis of CHF.
Hypouricemia and hyperuricemia in type 2 diabetes: two different phenotypes
Authors: Bo S. , Cavallo‐Perin P. , Gentile L. , Repetti E. , Pagano G.
Published: March 2003

Background and Design Conflicting data exist about uric acid levels in type 2 diabetes mellitus, as low levels were found in diabetic patients, while elevated serum uric acid is a feature of hyperinsulinemia and impaired glucose tolerance. The present study was addressed to evaluate the relation between uric acid and metabolic parameters, creatinine clearance and albumin excretion rate in a cohort of type 2 diabetic patients.

Results Hyperuricemic patients were older and had higher values of body mass index (BMI), systolic and diastolic blood pressure, triglycerides, albumin excretion rate, C‐peptide and prevalence of hypertension, metabolic syndrome and macroalbuminuria and lower values of high‐density lipoprotein (HDL)‐cholesterol, creatinine clearance and glycated haemoglobin (HbA1c). The correlations between uric acid levels and triglycerides, BMI, systolic blood pressure, albumin excretion rate, C‐peptide, creatinine clearance, HDL‐cholesterol and HbA1c remained significant in a multiple regression analysis after adjustment for age, sex and duration of diabetes. After performing multiple logistic regression analyses, uric acid levels were independently associated with hypertension [odds ratio (OR) = 1·8; 95% confidence interval (CI) 1·6–2], after adjustment for age, sex, duration of diabetes and macroalbuminuria (OR = 1·5; 95% CI 1·1–2·0), after adjustment for age, sex, HbA1c levels, creatinine clearance, duration of diabetes and blood pressure levels and the metabolic syndrome (OR = 1·6; 95% CI 1·5–1·8), after adjustment for age, sex and creatinine clearance.

Conclusions In type 2 diabetes, hyperuricemia seems to be associated with the insulin‐resistant syndrome and with early onset or increased progression to overt nephropathy, while hypouricemia is associated with worse metabolic control, hyperfiltration and a late onset or decreased progression to overt nephropathy.
N‐acetyl‐L‐cysteine exerts direct anti‐aggregating effect on human platelets
Authors: Anfossi G. , Russo I. , Massucco P. , Mattiello L. , Cavalot F. , Trovati M.
Published: March 2003

Background N‐acetyl‐l‐cysteine, a thiol compound, has been shown to potentiate the inhibition of platelet aggregation exerted by organic nitrates and to increase the anti‐aggregating effect of l‐arginine, which promotes endogenous synthesis of nitric oxide (NO) acting as substrate of platelet constitutive nitric oxide synthase (NOS). It is not known whether this thiol can exert direct effects on platelet aggregability.

Materials and methods 14 healthy male volunteers provided platelet samples to investigate whether N‐acetyl‐l‐cysteine directly influences platelet function and intraplatelet levels of 3′,5′ cyclic guanosine monophosphate (cGMP), which represents the second messenger involved in NO‐induced antiaggregation. Some experiments were repeated in the presence of NOS inhibitor NG‐monomethyl‐l‐arginine (L‐NMMA), of nitric oxide‐sensitive guanylyl cyclase inhibitor 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ), of the selective cGMP phosphodiesterase inhibitor zaprinast and of calcium ionophores (A23187, ionomycin).

Results N‐acetyl‐l‐cysteine at 3000–6000 µmol L−1 decreases the responses of human platelets both in platelet‐rich plasma (aggregation induced by adenosine 5‐diphosphate) and in whole blood (aggregation induced by collagen). The anti‐aggregating effect was prevented by preincubation with L‐NMMA and guanylyl cyclase inhibitor ODQ. In resting platelets, N‐acetyl‐l‐cysteine increased the levels of cGMP starting from a concentration of 3000 µmol L−1. Permeabilized platelets exhibited an increased sensitivity to the anti‐aggregating effect of N‐acetyl‐l‐cysteine. Also, cGMP phosphodiesterase inhibition or the increase in calcium availability, enhanced N‐acetyl‐l‐cysteine effects on platelets.

Conclusion N‐acetyl‐l‐cysteine exerts direct anti‐aggregating effects through an increased bioavailability of platelet nitric oxide.
Mitochondrial DNA deletion associated with the reduction of adenine nucleotides in human atrium and atrial fibrillation
Authors: Tsuboi M. , Hisatome I. , Morisaki T. , Tanaka M. , Tomikura Y. , Takeda S. , Shimoyama M. , Ohtahara A. , Ogino K. , Igawa O. , Shigemasa C. , Ohgi S. , Nanba E.
Published: March 2003

Background Structural changes in the number, size, and shape of mitochondria (mt) have been observed in the atrial muscles of patients with atrial fibrillation (AF) and of animals with rapid atrial pacing, however, it is not known whether the mitochondrial function is impaired in human atrium with AF.

Materials and Methods We determined adenine nucleotides concentrations and mtDNA deletions in 26 human right atria obtained at the time of cardiac surgery, using HPLC and PCR amplification, and studied the relationship between mtDNA deletions and clinical manifestations, the haemodynamic parameters of the patients and adenine nucleotide concentrations in their atrium.

Results The age and the prevalence of AF were significantly higher in the patients with a mtDNA deletion of 7·4 kb than in those without a deletion; there were no significant differences regarding haemodynamic parameters between the two groups. The concentrations of ATP, ADP, AMP and total adenine nucleotides in the right atrium were significantly lower in the patients with mtDNA deletions than the patients without a deletion. In a gender‐ and diseased‐matched population, the mtDNA deletion was still significantly associated with age and a decreased concentration of adenine nucleotides in the atrium. Using quantitative PCR analysis, the proportion of mtDNA deletion to normal mtDNA of the atrium, was estimated to be 0·3–2% in four cases.

Conclusion These results suggest that the deletion of mtDNA associated with ageing or AF can lead to a bioenergetic deficiency due to an impaired ATP synthesis in the human atrium; however, no conclusion can be made whether mtDNA deletion were the result or the cause of an impaired ATP synthesis, ageing, hemodynamic deterioration, or AF.
Leucine suppresses acid‐induced protein wasting in L6 rat muscle cells
Authors: Bevington A. , Brown J. , Walls J.
Published: March 2003

Background Metabolic acidosis induces protein wasting in skeletal muscle cells, accompanied by decreased glycolysis and compensatory increased consumption of other metabolic fuels, implying that protein wasting arises from fuel starvation and might be rectified by fuel supplements.

Design To test this hypothesis, total protein and protein degradation (release of 14C‐phenylalanine) were measured in L6 skeletal muscle cells cultured in Eagle's Minimum Essential Medium at pH 7·1–7·5 for 3 days with metabolic inhibitors or metabolic fuel supplements.

Results Inducing metabolic fuel starvation with inhibitors (1 mmol L−1 2‐deoxyglucose or 0·1 mmol L−1 KCN [potassium cyanide]) failed to stimulate protein degradation or net protein wasting under nonacidaemic conditions (pH 7·5). Conversely metabolic fuel supplements (1 mmol L−1 octanoate, pyruvate or alanine) failed to increase the protein content of the cultures at any pH tested, in spite of significant consumption of the fuels by the cells. Only leucine (1–3 mmol L−1) increased protein content and suppressed protein degradation in opposition to the catabolic effect of acidaemia (pH 7·1).

Conclusion Leucine exerts a beneficial anabolic effect on cultured skeletal muscle cells in the face of metabolic acidaemia. The failure of other metabolic fuels to do this, and of the metabolic inhibitors to exert a catabolic effect, suggests that leucine acts as a specific modulator of protein turnover and not as a nonspecific source of carbon for oxidation as a fuel.
Induction and treatment of the antiphospholipid syndrome – lessons from animal models
Authors: Shoenfeld Y. , Blank M. , Sherer Y.
Published: March 2003

The diagnosis of antiphospholipid syndrome (APS) is based on a combination of clinical and serological criteria. This review summarizes the literature regarding animal models of APS. Animal models of this syndrome help to elucidate pathogenic roles of the characteristic antiphospholipid antibodies in pregnancy morbidity, vascular thrombosis, neurologic disease and atherosclerosis. Furthermore, these models also provide measures to evaluate novel therapies for APS. These include bone‐marrow transplantation, intravenous immunoglobulin, anticoagulation, interleukin‐3, in addition to other therapies. Experimental induction and treatment of APS largely contributes to our understanding of the disease and to better management of its clinical characteristics.
Homocysteine levels in patients treated with lipid apheresis: effect of a vitamin therapy
Authors: Julius U , Pietzsch J. , Gromeier S. , Schorr H. , Herrmann W.
Published: March 2003

Background Patients treated with lipid apheresis already suffer from familial hypercholesterolemia and severe coronary heart disease: any additional risk factor is dangerous for these patients. Hyperhomocysteinemia has been recognized as an independent risk factor for atherosclerotic disease. We checked the frequency of hyperhomocysteinemia in lipid apheresis patients and measured the effect of a vitamin therapy.

Materials and Methods Sixteen heterozygous patients (10 males, 6 females) were studied, who were being treated by three different apheresis procedures. Homocysteine was measured using an enzyme conversion immunoassay. Cystathionine and methylmalonic acid were assessed by gas chromatography/mass spectrometry. Serum levels of folic acid, vitamin B12, and vitamin B6 were also determined. The patients received a vitamin therapy (3 mg folate, 60 µg cyanocobalamine, 10 mg pyridoxine hydrochloride daily) for 12 weeks.

Results In 9 out of 16 patients, plasma homocysteine levels were found to be elevated (> 12 µmol L−1). Cystathionine concentrations were also increased, especially in those patients with elevated homocysteine. Methylmalonic acid levels were not elevated. Serum folic acid, vitamin B6, and vitamin B12 concentrations were initially in the normal range and not correlated to plasma homocysteine. The vitamin therapy reduced the plasma homocysteine concentrations in all patients significantly by 33%. Among those patients with elevated homocysteine levels, the optimal range < 12 µmol L−1 for homocysteine was rarely reached.

Conclusions In patients treated with lipid apheresis, a hyperhomocysteinemia can be frequently seen. The constellation of both elevated homocysteine and cystathionine levels points to the existence of tissue vitamin deficiencies, folate and vitamin B‐6, which were improved by vitamin supplements. Because methylmalonic acid was mostly normal, a vitamin B‐12 deficiency was not proven.
Assessment of the left ventricular diastolic reserve in essential hypertension: the acute saline load test
Authors: Triposkiadis F. , Moyssakis I. , Makris T. , Hatzizaharias A. , Hadjinikolaou L. , Kyriakidis M.
Published: March 2003

Objectives

The aim of this study was to evaluate the significance of the development of a restrictive response to an acute saline load, defined as an increase in the ratio of peak early to peak late diastolic transmitral flow velocity (E/A ratio) associated with a decrease in the deceleration time, in patients with mild to moderate untreated hypertension.

Background

Recognised abnormal patterns of transmitral diastolic flow include, from ‘best’ to ‘worst’: prolonged relaxation, pseudonormalisation, and restrictive physiology. The common denominator of these transitions is the constellation of an increase in the E/A ratio associated with a decrease in deceleration time.

Patients and Methods

Sixteen normal control subjects (6 males, 10 females, age 51·6 ± 6·9 years) and 24 patients with mild to moderate untreated hypertension (12 males, 12 females, age 46·8 ± 7·5 years) underwent supine blood pressure measurement with sphygmomanometry, biochemical studies, and transthoracic M‐mode, 2D, and Doppler echocardiography before and after an acute saline load (7 mL kg−1, maximum 500 mL, NaCl 0·9% within 15 min IV).

Results

The baseline E/A ratio was lower (0·90 ± 0·14 vs. 1·04 ± 0·18; P < 0·01) and the deceleration time was longer (158·8 ± 19·4 vs. 135 ± 8·9 ms; P < 0·01) in patients with hypertension compared with normotensive controls. However, no patient with hypertension exhibited a transmitral flow velocity pattern compatible with typical prolonged relaxation. A restrictive response to the acute saline load was observed in 12 (50%) of the hypertensive and none of the control subjects. Hypertensive patients with a restrictive response to the acute saline load had a lower baseline E velocity (54·8 ± 8·7 cm s−1 vs. 66 ± 6·4 cm s−1; P = 0·003), a lower baseline E/A ratio (0·83 ± 0·13 vs. 0·97 ± 0·12; P = 0·015), and a longer deceleration time (167·5 ± 15·4 ms vs. 150 ± 19·5; P = 0·03) than hypertensive patients without such a response.

Conclusion

A restrictive response to an acute saline load is indicative of a limited diastolic reserve in patients with mild to moderate untreated hypertension. Further studies are required in order to evaluate the significance of such a response with regards to risk stratification and efficacy of medical treatment in this patient population.
A noninvasive method to collect nasally exhaled air condensate in humans of all ages
Authors: Griese M. , Latzin P. , Beck J.
Published: March 2003

Background The analysis of exhaled breath condensate may provide valuable insights into inflammatory and other metabolic processes of the lungs. However, its collection by active exhalation with conventional methods is cumbersome, demands a substantial level of co‐operation with high motivation and is very difficult or impossible in children younger than about 4–6 years or in the elderly. A comfortable, noninvasive and efficient method is desirable.

Design and patients For collection a high‐performance pump connected to a cold trap and nasal prongs were used. The volume of the condensate collected was assessed in 141 children of all ages and five adults. As an example for a low molecular component, H2O2 a marker of oxidative stress, was determined fluorometrically.

Results On average, in healthy children from 4 weeks to 18 years of age, 84·0 (79·4, 87·3) µL min−1 of nasally exhaled air condensate were collected. The volume obtained was about 45% less in 1–6‐year‐old children, increased linearly with collection time, and averaged about 20–30% of the exhaled water vapour. The concentration of H2O2 in the healthy children was 0·49 (0·48, 0·61) μM and did not depend on age, the time of the day, family, or personal history of atopy and sex.

Conclusions The method described is generally applicable, comfortable, noninvasive, safe and efficient and allows the collection of nasally exhaled air condensate for the evaluation of metabolic processes of the lungs.
ACE and angiotensinogen gene genotypes and left ventricular mass in athletes
Authors: Diet F. , Graf C. , Mahnke N. , Wassmer G. , Predel H. G. , Palma‐Hohmann I. , Rost R. , Böhm M.
Published: March 2003

Background Genetic factors may be important in modifying heart size due to long‐term athletic training. The significance of polymorphisms of genes of the renin–angiotensin system in myocardial mass in a population of athletes participating in different disciplines is not known.

Methods The angiotensin I‐converting enzyme gene insertion/deletion (I/D) polymorphism, angiotensinogen gene M235T polymorphism and angiotensin II type 1 receptor gene A1166C polymorphism were determined in 83 male Caucasian endurance athletes and associated with left ventricular mass.

Results No association with left ventricular mass was found for the polymorphisms of angiotensin I‐converting enzyme gene I/D, angiotensinogen gene M235T and angiotensin II type 1 gene A1166C when studied separately. However, combined analysis of the angiotensin I‐converting enzyme gene I/D polymorphism and angiotensinogen gene M235T polymorphism genotypes suggested an association with left ventricular mass (g m−2) (P = 0·023). Athletes with the angiotensin I‐converting enzyme gene DD/angiotensinogen gene TT genotype combination had greater left ventricular mass compared with all other genotype combinations (179·8 ± 26·1 g m−2 vs. 145·2 ± 27·3 g m−2, P = 0·003).

Conclusions These results suggest an association of combined angiotensin I‐converting enzyme gene I/D polymorphism genotypes, and angiotensinogen gene M235T polymorphism genotypes with left ventricular hypertrophy due to long‐term athletic training. A synergistic effect of angiotensin I‐converting enzyme gene DD genotype and angiotensinogen gene TT genotype on left ventricular mass in endurance athletes appears to occur.
Detection of cytochrome P450 mRNA transcripts in prostate samples by RT‐PCR
Authors: Finnström N. , Bjelfman C. , Söderström T. G. , Smith G. , Egevad L. , Norlén B. J. , Wolf C. R. , Rane A.
Published: March 2003

Background The expression of cytochrome P450 (CYP)‐dependent mono‐oxygenases in the prostate is important, as it will determine the rate of activation of potential carcinogens as well as the metabolism of hormones with implications in diseases of the prostate. In addition, the levels of cytochromes P450 in prostatic tumours may well be determinants of the outcome of therapy involving P450 substrates such as anti‐androgens.

Methods The gene expression of 12 different CYP genes was measured by reverse transcription–polymerase chain reaction (RT‐PCR) in a total of 28 human prostatic tumour and nontumour samples.

Results Intriguingly, a large number of CYP mRNAs were detected in the prostate samples, including CYP1A2, ‐1B1, ‐2C19, ‐2D6, ‐3A4, ‐3A5, ‐3A7 and ‐4B1. CYP1B1 was consistently expressed and CYP3A5 and CYP4B1 were expressed in a majority of the samples tested.

Conclusions These data demonstrate a wide range of CYP genes being expressed in the prostate. The relative importance of these enzymes in the pathogenesis and treatment of prostatic disease remains an important theme for further study.
Oral nitric oxide during plaque deposition
Authors: Carossa S. , Pera P. , Doglio P. , Lombardo S. , Colagrande P. , Brussino L. , Rolla G. , Bucca C.
Published: March 2003

Background Nitric oxide (NO) is one of the most powerful antibacterial compounds. We investigated if NO oral production increases during dental plaque deposition.

Materials and methods Oral NO and salivary nitrite were measured in 31 healthy subjects – 11 smokers and 20 nonsmokers – with natural healthy teeth, in the morning after tooth cleaning (baseline), after withdrawal of oral hygiene for 24 h and again after tooth cleaning.

Results NO and nitrite were significantly higher during plaque deposition than with clean teeth: mean NO values ± SEM were 44·3 ± 4·9 parts per billion (ppb) at baseline, 58·8 ± 3·7 ppb with plaque and 43·6 ± 3·7 ppb after tooth cleaning, P < 0·05; nitrite values were 32·9 ± 5·5 µm at baseline, 66·4 ± 8·2 with plaque and 37·5 ± 5·5 after tooth cleaning, P < 0·01. During plaque deposition, oral NO was significantly directly related to salivary nitrite (r = 0·497, P = 0·002) and so were their respective changes after tooth cleaning (r = 0·577, P < 0·001). Smokers had significantly lower oral NO than nonsmokers, with both clean and dirty teeth (P < 0·001), and higher bacteria counts in the plaque (38·6 ± 11·5 vs. 19·9 ± 2·3, P = 0·046).

Conclusions Oral NO production increases during de novo deposition of dental plaque. NO might be an early host defence mechanism against bacterial proliferation in the plaque. Such a mechanism is inhibited by cigarette smoking.
Hyperhomocysteinaemia and folate deficiency in human immunodeficiency virus‐infected children
Authors: Vilaseca M. A. , Sierra C. , Colomé C. , Artuch R. , Valls C. , Muñoz‐Almagro C. , Vilches M‐A. , Fortuny C.
Published: March 2003

Our aim was the detection of possible deficiencies of folate and cobalamin by the measurement of plasma total homocysteine (tHcy) in 69 human immunodeficiency virus (HIV) ‐infected children on antiretroviral treatment. We studied the relationship of these vitamins and methionine with tHcy values.

Plasma tHcy was determined by high‐performance liquid chromatography with fluorescence detection, folate and cobalamin by competitive protein‐binding chemiluminescence, and methionine by ion exchange chromatography.

Significant differences were observed between tHcy concentrations in the HIV‐infected patients and the reference values for children of similar ages (P < 0·0001). Folate values were significantly lower in HIV‐infected children compared with our reference paediatric population (P < 0·0001), but cobalamin concentrations were similar between patients and reference values. A significantly negative correlation was found between tHcy and folate (r = − 0·596; P < 0·0001), and a significantly positive correlation between folate and the methionine : tHcy ratio (r = 0·501; P < 0·0001). Plasma tHcy was significantly higher (P = 0·008), while folate values and methionine : tHcy ratios were significantly lower (P = 0·007 and P = 0·042), in patients on protease inhibitor treatment than in patients on other antiretroviral therapies.

The hyperhomocysteinaemia and low methionine : tHcy ratios observed in our group of HIV‐infected children are probably a consequence of the low folate values, which interfere in the remethylation of homocysteine to methionine. Patients on protease inhibitor treatment showed significantly higher plasma tHcy concentrations, and lower folate values and methionine : tHcy ratios, compared with patients on other antiretroviral therapies. Hyperhomocysteinaemia is associated with the risk of premature stroke, which may have adverse consequences in the evolution of disease.
Increased cytokine release by leucocytes in survivors of stroke at young age
Authors: Grau A. J. , Aulmann M. , Lichy C. , Meiser H. , Buggle F. , Brandt T. , Grond‐Ginsbach C.
Published: March 2003

Enhanced stimulus‐induced release of pro‐inflammatory cytokines by leucocytes may contribute to the pathogenesis of ischaemic stroke.

We investigated the lipopolysaccharide‐induced release of interleukin‐1β (IL‐1β), IL‐6, IL‐8, and tumour necrosis factor‐α (TNF‐α) in whole blood from 20 patients with a history of ischaemic stroke under the age of 50, 20 patients with a history of cervical artery dissection (CAD) and 21 age‐ and sex‐matched healthy control subjects.

Release of IL‐8 was higher (P = 0·006) and release of TNF‐α and IL‐6 tended to be higher (P < 0·1) in young stroke patients than in control subjects. No increased release existed in CAD patients. Vascular risk factors or history of infection before stroke did not modify IL‐8 production. A common T(250) → A polymorphism in the IL‐8 gene promotor was newly identified but did not correlate with the variability of IL‐8 release. The C(260) → T polymorphism in the gene of the monocytic LPS‐receptor CD14 – a risk factor for myocardial infarction – was not associated with increased cytokine release.

We conclude that high inducible release of IL‐8 – and possibly of TNF‐α and IL‐6 – may contribute to the odds of ischaemic stroke in young adults.
Insulin resistance affects the regulation of lipoprotein lipase in the postprandial period and in an adipose tissue‐specific manner
Authors: Panarotto D. , Rémillard P. , Bouffard L. , Maheux P.
Published: March 2003

Aims Insulin is a potent stimulator of adipose tissue lipoprotein lipase (LPL). Logically, the postprandial period is therefore a privileged time of the day for the regulation of LPL by insulin in this tissue. It is not clear to what extent a defect such as insulin resistance could affect this regulation and contribute to postprandial, as well as fasting, hypertriglyceridaemia. The aim of the present protocol was to study the relationship between insulin resistance and LPL in adipose tissue and in plasma, in the particular context of the postprandial period.

Methods For this study, 26 adult nondiabetic individuals (12 women and 14 men) with a wide range of whole‐body insulin‐mediated glucose uptake (as assessed with an insulin suppression test) were studied. An abdominal subcutaneous fat biopsy on one occasion, and post‐heparin plasma on another occasion, were obtained 4 h into a standardized meal profile administered in the fasting state.

Results Postprandial triglyceride excursions (evaluated by the incremental area under the curve during the metabolic meal profile) were inversely correlated to adipose tissue LPL mRNA levels (ρ = −0·43, P < 0·03) as well as to adipose tissue LPL heparin‐releasable activity (ρ = −0·58, P < 0·01). Steady‐state plasma glucose (SSPG) concentrations during the insulin suppression test, a reflection of the degree of insulin resistance, were also negatively correlated to adipose tissue LPL mRNA (ρ = −0·50, P < 0·02) and activity (ρ = −0·56, P < 0·01). There was no correlation between plasma post‐heparin LPL activity/mass and postprandial triglycerides nor with insulin resistance.

Conclusion Regulation of adipose tissue LPL is significantly affected in insulin‐resistant individuals in the postprandial period. This presumed impaired effect of insulin on LPL postprandially could be an important contributor to the atherogenic dyslipidaemia described in insulin resistance syndrome.
Matrix metalloproteinase‐9 is elevated in serum of alcohol abusers
Authors: Sillanaukee P. , Kalela A. , Seppä K. , Höyhtyä M. , Nikkari S. T.
Published: March 2003

Background Moderate alcohol consumption has been shown to protect against coronary heart disease. However, excessive alcohol use has been suggested to have detrimental effects on the cardiovascular system. We examined whether there is an association between alcohol abuse and circulating levels of matrix metalloproteinase‐9 (MMP‐9), which has been linked to unstable coronary heart disease and arterial inflammation.

Design Serum MMP‐9 concentrations were compared between 40 male alcoholics (mean age 42 years) with ethanol consumption > 1000 g week−1 and 40 social drinker males with an ethanol consumption of < 200 g week−1 (mean age 45 years).

Results The mean serum MMP‐9 concentration was significantly higher in sera of alcoholics compared to control subjects (70·9 ± 47·7 g L−1 and 43·1 ± 19·2 g L−1, respectively; P = 0·001). Within the alcoholic group, MMP‐9 concentration did not correlate with age, gamma glutamyl transferase, carbohydrate‐deficient transferrin, aspartate aminotransferase, alanine aminotransferase or alkaline phosphatase.

Conclusion Our finding of elevated MMP‐9 concentrations in sera of chronic alcohol abusers helps understand the mechanisms of cardiovascular risk among these subjects.