Self-paced cycling performance and recovery under a hot and highly humid environment after cooling.

AIM: This study investigated the effects of pre- and post-cooling on self-paced time-trial cycling performance and recovery of cyclists exercising under a hot and highly humid environment (29.92 °C-78.52% RH). METHODS: Ten male cyclists performed a self-paced 20-min time trial test (TT20) on a cyclo-ergometer while being cooled by a cooling vest and a refrigerating headband during the warm-up and the recovery period. Heart rate, power output, perceived exertion, thermal comfort, skin and rectal temperatures were recorded. RESULTS: Compared to control condition (222.78 ± 47 W), a significant increase (P<0.05) in the mean power output during the TT20 (239.07 ± 45 W; +7.31%) was recorded with a significant (P<0.05) decrease in skin temperature without affecting perceived exertion, heart rate, or rectal temperature at the end of the TT20. However, pace changes occurred independently of skin or rectal temperatures variations but a significant difference (P<0.05) in the body's heat storage was observed between both conditions. This result suggests that a central programmer using body's heat storage as an input may influence self-paced time-trial performance. During the recovery period, post-cooling significantly decreased heart rate, skin and rectal temperatures, and improved significantly (P<0.05) thermal comfort. CONCLUSION: Therefore, in hot and humid environments, wearing a cooling vest and a refrigerating headband during warm-up improves self-paced performance, and appears to be an effective mean of reaching skin rest temperatures more rapidly during recovery.

Involvement of melanocortin receptor accessory proteins (MRAPs) in the function of melanocortin receptors.

The melanocortin system integrates different agonists, competitive or inverse agonists, and receptors. Recent investigations have also discovered a specific system of melanocortin receptor accessory proteins (MRAPs) that are involved in the regulation of the functional expression of these receptors. MRAP1 mutations are responsible for type 2 familial glucocorticoid deficiency (FGD2), a rare autosomal disorder characterized by high plasma adrenocorticotropin hormone (ACTH) levels but severe cortisol deficiency. ACTH binds melanocortin 2 receptor (MC2R), a G protein-coupled receptor, in the adrenal gland to promote corticosteroid synthesis. In the absence of MRAP1, MC2R cannot translocate from the endoplasmic reticulum to the plasma membrane and ACTH-induced signaling is extinguished. A second MRAP protein, called MRAP2, also modulates MC2R activity. MRAPs also interact with the other melanocortin receptors, adjusting their pharmacological properties. In this paper, we briefly review the MRAP system and its interaction with melanocortin receptors.

Stimulating effect of growth hormone on type IV collagen production by endothelial cells cultured in normal and high glucose.

Collagen IV accumulation is characteristic of diabetic angiopathy. To test the possible contribution of GH, we studied its effects on collagen IV production by human umbilical vein endothelial cells at 5.5 and 16.7 mmol/l glucose. GH (100 ng/ml) markedly increased collagen IV level in the culture supernatant and in the insoluble extracellular matrix and cell fraction at both glucose concentrations. This stimulating effect of GH was additional to that of high glucose. It was more pronounced on collagen IV than on total protein synthesis. GH increased free latent gelatinase activity slightly at normal and markedly at high glucose. Using GF109203X, a PKC inhibitor, we observed that high glucose, but not GH, activated PKC. These two factors stimulating collagen IV production appear to work through different pathways, favoring an additivity of their effects. This supports the contribution of high plasma GH in diabetic vascular basement membrane thickening.

The estrogen receptor of the gastropod Nucella lapillus: modulation following exposure to an estrogenic effluent?

The molecular targets of estrogenic endocrine disrupting chemicals have been studied in detail in vertebrates. The lack of basic endocrine knowledge impairs similar approaches for invertebrates. Evidence indicates that the signalling pathways of invertebrates may also be a target of estrogenic chemicals (ECs). In fact, the exposure to effluents containing ECs has been reported to impact mollusc reproduction. Despite the reported estrogen independence of the mollusc nuclear estrogen receptor (ER), its role in EC-induced toxicity has not been investigated in vivo. Therefore, we have cloned the ER of the gastropod Nucella lapillus and evaluated the effects of a mixture of estrogenic chemicals (sewage effluent) on its expression in the ovary. Here, we show that the exposure to a raw domestic/industrial effluent, impact ER expression with a simultaneous reproductive maturation. These results highlight the need to further investigate the role of ER on the reproductive process in prosobranch gastropods and whether this signalling pathway is prone to disruption by ECs.

Assessment of a polyelectrolyte multilayer film coating loaded with BMP-2 on titanium and PEEK implants in the rabbit femoral condyle.

UNLABELLED: The aim of this study was to evaluate the osseointegration of titanium implants (Ti-6Al-4V, noted here TA6V) and poly(etheretherketone) PEEK implants induced by a BMP-2-delivering surface coating made of polyelectrolyte multilayer films. The in vitro bioactivity of the polyelectrolyte film-coated implants was assessed using the alkaline phosphatase assay. BMP-2-coated TA6V and PEEK implants with a total dose of 9.3µg of BMP-2 were inserted into the femoral condyles of New Zealand white rabbits and compared to uncoated implants. Rabbits were sacrificed 4 and 8weeks after implantation. Histomorphometric analyses on TA6V and PEEK implants and microcomputed tomography on PEEK implants revealed that the bone-to-implant contact and bone area around the implants were significantly lower for the BMP-2-coated implants than for the bare implants. This was confirmed by scanning electron microscopy imaging. This difference was more pronounced at 4weeks in comparison to the 8-week time point. However, bone growth inside the hexagonal upper hollow cavity of the screws was higher in the case of the BMP-2 coated implants. Overall, this study shows that a high dose of BMP-2 leads to localized and temporary bone impairment, and that the dose of BMP-2 delivered at the surface of an implant needs to be carefully optimized. STATEMENT OF SIGNIFICANCE: The presentation of growth factors from material surfaces currently presents significant challenges in academia, clinics and industry. Applying osteoinductive factors to different types of implants, made of metals or polymers, may improve bone repair in difficult situations. Here, we show the effects of an osteoinductive coating made of polyelectrolyte multilayer films on two widely used materials, titanium TA6V alloys and PEEK implants, which were implanted in the rabbit femoral condyle. We show that a too high dose of BMP-2 delivered from the screw surface has a negative short-term effect on bone regeneration in close vicinity of the screw surface. In contrast, bone formation was increased at early times in the empty spaces around the screw. These results highlight the need for future dose-dependence studies on bone formation in response to osteoinductive coatings.

Ultrastructural aspects of the liver perisinusoidal space in diabetic patients with and without microangiopathy.

To determine whether abnormalities of the perisinusoidal space of Disse are present in the liver of diabetic patients with microangiopathy, an ultrastructural stereologic study of the space of Disse was performed in six insulin-treated diabetics with severe performed in six insulin-treated diabetics with severe proliferative retinopathy and six insulin-treated diabetics with normal fluorescein angiography, six patients with familial unconjugated hyperbilirubinemia were studied as controls. No patient had clinical and/or biochemical hepatic abnormalities and none suffered from any of the pathologic conditions known to be associated with collagenization of the perisinusoidal space. In control patients, the space of Disse of liver sinusoids contained occasional small deposits of collagen fibers. The relative volume of these fibers per unit of sinusoid represented 2.63 +/- 0.82%. In all diabetic patients with retinopathy, marked deposition of collagen fibers within the perisinusoidal space was constantly observed, a finding confirmed by ultrastructural stereologic analysis which showed that the relative volume of collagen fibers per unit of sinusoid represented 7.33 +/- 1.44% and differed significantly from control patient values (P less than 0.001). On the contrary, the relative volume of collagen fibers within the space of Disse in diabetic patients without retinopathy (3.95 +/- 2.96%) did not differ significantly from control patient values. These findings demonstrate that collagenization of the space of Disse is positively correlated with the presence of diabetic microangiopathy. Ultrastructural examination of the liver sinusoids might constitute a sensitive and useful approach for detecting the early changes of the microcirculation in diabetic patients.

Fas/Fas-Ligand pathway is impaired in patients with type 2 diabetes. Influence of hypertension and insulin resistance.

OBJECTIVES: In type 2 diabetic patients with no cardiac history or symptoms, 1) to evaluate whether the soluble forms of Fas (sFas) and Fas-ligand (sFasL), involved in apoptosis, may be markers of silent coronary disease or related to hypertension or microangiopathic complications; 2) to examine the effect of short-term glycemic control on sFas and sFasL. METHODS: (1) sFas and sFasL were measured with the ELISA method in 44 asymptomatic diabetic patients, 33 with hypertension, and with a normal myocardial scintigraphy (n=14), with silent myocardial ischemia (SMI) and without (n=15) or with (n=15) significant coronary stenoses; and in 14 controls; (2) sFas and sFasL were measured in 15 poorly controlled diabetic patients before and after 7 days of CSII treatment. RESULTS: (1) sFas and sFasL differed in the four groups of patients (p=0.003 each). sFas was significantly higher in the patients with SMI without (p=0.035) and with coronary stenoses (p=0.002) than in the control group. sFasL was lower in the three groups of diabetic patients (p<0.05 each) than in control group. In the diabetic population, sFas correlated positively with hypertension (p=0.021), and sFasL negatively with hypertension (p=0.027) and HOMA index in the non-insulin treated patients (p=0.049); (2) sFas did not differ before or after CSII, and there was a marginal decrease in sFasL. CONCLUSION: Fas-mediated apoptosis is involved in type 2 diabetes and might be associated with hypertension and/or its vascular consequences. sFasL might be affected by insulin resistance. sFas and sFasL are not effective markers of SMI.

Synthesis and characterization of [Fe(BPMEN)ACC]SbF6: a structural and functional mimic of ACC-oxidase.

A mononuclear Fe(II) complex bearing 1-aminocyclopropane-1-carboxylic acid (ACCH) was synthesized and characterized. X-ray crystallography demonstrated that ACC binds to the Fe(II) ion in a bidentate mode constituting the first structural mimic of the expected binding of ACC to the Fe(II) center of the ethylene forming enzyme ACC-oxidase (ACCO). [Fe(BPMEN)ACC]SbF6 also constitutes a functional biomimetic complex of ACCO, as it reacts with hydrogen peroxide producing ethylene.

Gallium(III)- and calcium(II)-catalyzed Meyer-Schuster rearrangements followed by intramolecular aldol condensation or endo-Michael addition.

The first gallium- and calcium-catalyzed Meyer-Schuster rearrangements are described. Under substrate control, the incipient conjugated ketones can be trapped intramolecularly by ß-keto esters or amides to yield cyclic products after aldol condensation or endo-Michael addition. An interesting additive effect that promotes the latter tandem process with calcium has been found.

Renal and microvascular effects of an aldose reductase inhibitor in experimental diabetes. Biochemical, functional and ultrastructural studies.

Aldose reductase inhibitors, and particularly sorbinil, have been reported to prevent glomerular basement membrane thickening (GBMT) and albuminuria development in diabetic rats, but contradictory observations have been published. The aim of this study was to answer the following questions (i) is the corrective effect of sorbinil on GBMT, if confirmed, associated with an effect on collagen metabolism alterations? (ii) Is it associated with an effect on microvascular functional alterations? We therefore studied the influence of sorbinil on glucosyl-galactosyl-hydroxylysyl-glucohydrolase activity (GGHG; EC 3.2.1.107 which is involved in the catabolism of collagen disaccharide units), 3- and 4-hydroxyproline content and GBMT by ultrastructural morphometry in the kidney cortex of streptozotocin-diabetic rats after 5 months of disease. In parallel, the effects on albumin renal clearance and another functional alteration, the microvascular response to norepinephrine, were evaluated. We confirmed a corrective effect of sorbinil on both renal albumin clearance and GBMT. In the diabetic rats, sorbinil diminished the 3-hydroxyproline (but not the 4-hydroxyproline) content, whether expressed per mg protein or per total kidney cortex relative to body weight. Sorbinil reduced GGHG activity measured in the dialysed 10,000 g supernatant whether expressed per mg protein or per total kidney cortex; this activity has been shown to be increased in diabetes. Sorbinil also corrected the microvascular response to norepinephrine which is altered in diabetes.

Relation between pancreatic islet cellular infiltration and plasma fibrinogen or alpha 1-acid glycoprotein levels in spontaneously and streptozotocin-diabetic rats: an increase in these protein levels is not necessary for inducing microcirculatory erythrocyte velocity alteration.

Plasma levels of fibrinogen, alpha 1-acid glycoprotein (AG) and albumin, pancreatic insulitis quantitative scores, and erythrocyte velocity in the mesoappendix microvessels were measured in BB diabetic (BBD) and streptozotocin-diabetic rats (WSTZ) in order to answer the following questions: (a) Does hyperfibrinogenemia or increase in AG plasma level occur in BBD and WSTZ rats, and if so, are these alterations secondary to the hyperglycemia or to an inflammatory process such as insulitis? (b) Is there a decrease in microcirculatory flow in the BBD and WSTZ rats, and if so, is it secondary to the hyperfibrinogenemia and/or the hyperglycemia? Insulitis was present in the BBD rats after 5 weeks of disease (with a score of 2.9 +/- 0.1 vs. 1.4 +/- 0.6 in the normoglycemic controls), but absent in WSTZ rats after 5 months of disease (1.2 +/- 0.06 vs. 1.1 +/- 0.06). Increase in fibrinogen and AG plasma levels was observed in the BBD rats only and appears linked to the insulitis. The major acute phase protein AG level is increased in BBD rats already on the first day of appearance of glycosuria. In the WSTZ rats, without insulitis, chronic hyperglycemia alone did not induce an increase in fibrinogen and AG plasma levels. A decreased microcirculatory erythrocyte velocity has been found in both BBD and WSTZ rats. Thus an increase in fibrinogen or AG plasma levels is not necessary for inducing a decrease in erythrocyte velocity. Hyperglycemia is probably the main factor responsible for the decrease in microcirculatory flow in the BBD and WSTZ rats.

Effect of long-term treatment with a purified micronized flavonoid fraction on pancreatic mononuclear cell infiltration in diabetic BB rats.

Bio Breeding (BB) rats develop a genetically determined insulin-dependent diabetes, because of the early destruction of pancreatic beta cells of Langerhans islets, massively infiltrated by inflammatory mononuclear cells. S 5682, registered as Daflon, 500 mg, is a purified micronized flavonoid fraction (90% diosmin, 10% hesperidin), which has been shown to possess antiinflammatory properties, including anti-free radical activity, effects on vascular permeability, venous tone, and perivenous inflammation. We studied the effect of S 5682 on the course of pancreatic insulitis in diabetic BB rats. All the diabetic BB rats were hyperglycemic, with an increase of plasma levels of fructosamine, alpha-1 acid glycoprotein, and fibrinogen, and a dramatic decrease of C-peptide level. These parameters were not modified by S 5682. Pancreas histologic studies showed that in S 5682-treated diabetic BB rats, lymphocytic infiltration of Langerhans islets was less important and frequent than in untreated diabetic BB rats. By quantitative analysis, a highly significant difference was observed for insulitis, as well as perivasculitis, between S 5682-treated and untreated diabetic BB rats. This inhibitory effect of S 5682 on pancreatic mononuclear cell infiltration may be useful for a complementary treatment to decrease the development of insulitis in human insulin-dependent diabetes mellitus.

Increased levels of soluble Fas in serum from diabetic patients with neuropathy.

OBJECTIVE: The aim of this study was to investigate circulating soluble Fas (sFas) and Fas ligand (sFasL), two transmembrane glycoproteins involved in apoptosis, in the serum of diabetic patients. MATERIAL AND METHODS: We assessed sFas and sFasL serum levels in normal controls (n=15), and in both 42 diabetic patients without complications, or with predominant retinopathy or neuropathy, using sFas and sFasL specific ELISA method. RESULTS: sFasL serum levels were less than 0.1 ng/ml in normal controls and in each group of diabetic patients. In diabetic patients with a predominant neuropathy, sFas serum levels were significantly increased not only when compared with normal controls (13.5 +/- 3.6 ng/ml vs 7.1 +/- 1.1 ng/ml, p<0.001), but also when compared with patients without complications (vs 9.1 +/- 1.8 ng/ml, p<0.001) or with a predominant retinopathy (vs 8.7 +/- 1.9 ng/ml, p<0.001). CONCLUSIONS: These preliminary data suggest that a dysregulation of the Fas system in peripheral neuronal cells may be involved in the increase of sFas observed in diabetic patients with neuropathy.

Case report: systemic hypersensitivity reaction to goserelin acetate.

Women suffering from endometriosis are treated with long-acting analogues of gonadotropin-releasing hormone (GnRH). This is a case of hypersensitivity reaction to a goserelin acetate implant that manifested as an anaphylactic reaction. This is the first report of a hypersensitivity reaction to the GnRH analogue, goserelin acetate (Zoladex, Zeneca Pharmaceuticals, Wilmington, DE).

[Cell cultures. Complementary or alternative methods to animal experimentation]. / Les cultures cellulaires. Méthodes complémentaires ou alternatives à l'expérimentation animale.

In vitro methods, which appeared at the beginning of the century, have had exponential development since one decade for ethical and technological reasons. They can be used for studies concerning intracellular, intercellular or environmental activities. Despite of limiting factors, these techniques offer certain advantages which have to be optimized in order to be validated. They are actually complementary, used for exploratory purposes. In the future, they could replace partially but not completely some in vivo experiments.

A flavonoid fraction purified from Rutaceae aurantiae (Daflon(R)) inhibiting AGE formation, reduces urinary albumin clearance and corrects hypoalbuminemia in normotensive and hypertensive diabetic rats.

AIM: Advanced glycation endproducts (AGEs) have been shown to contribute to alteration of glomerular permselectivity to proteins in diabetes. Oxidative stress is required for AGE formation. Therefore we studied the effect of an antioxidant micronized purified flavonoid fraction (MPFF, Daflon(R) 500 mg), on urinary albumin clearance in diabetic rats. METHODS: Hyperglycaemia was induced by streptozotocin 55 mg/kg IM at days 0 and 7 in normotensive Wistar rats (NWR, diabetes duration 5 months) or hypertensive Wistar Kyoto rats (SHR, diabetes duration 2 months). MPFF was administered at 300 mg/kg/day, from day -2 until sacrifice. RESULTS: After 5 months of diabetes in NWR, MPFF reduced albumin clearance from 729±92 to 392±60 nl/min/kg, p<0.01, and restored albuminemia from 20.4±0.9 to 24.0±1 g/l, p<0.05; albumin fractional clearance was significantly diminished in the flavonoid-treated diabetic rats (0.360±0.037‰ versus 1.335±0.430‰ in the diabetic controls, p<0.001); MPFF did not significantly modify blood glucose and plasma fructosamine levels. After 2 months of diabetes in SHR, MPFF reduced albumin clearance from 243±121 to 101±47 nl/min/kg, p<0.05, and restored albuminemia from 21.1±1.6 to 26.7±2.2 g/l (p<0.05); MPFF also decreased plasma fluorescence characteristic of AGEs (p<0.02). Besides hesperetin, a main metabolite of MPFF recovered in plasma, inhibited in vitro the formation of the crosslinking AGE pentosidine in collagen incubated with high glucose (p<0.001). CONCLUSION: Our results confirm the role of glycoxidative stress in diabetic nephropathy. MPFF might be useful as complementary treatment for preventing diabetic microangiopathy.

Anti-androgenic effects of sewage treatment plant effluents in the prosobranch gastropod Nucella lapillus.

Recent studies performed under laboratory conditions have shown that single exposure to high levels of several xenoestrogens is able to induce imposex in at least two neogastropod species. In an attempt to evaluate if xenoestrogens, at environmentally relevant conditions, do contribute to imposex induction, we have tested the effects of a mixture containing xenoestrogens (municipal sewage effluents) on imposex development in the dogwhelk Nucella lapillus. Exposure for 3 months to the raw (0.25% and 1%) and the final sewage effluent (12.5% and 50%) rendered no increase in the severity of imposex. Conversely, as exposure to high concentrations of natural steroids, estradiol and estrone, had previously been shown to partially rescue imposex development under laboratory conditions, we have also tested if exposure to the final sewage effluent could ameliorated the severity of imposex induction by tributyltin (TBT). The results demonstrated that co-exposure to the final sewage effluent leads to a decrease trend in the severity of imposex in the presence of TBT. Within the studied imposex parameters, the Relative Penis Size index (RPSI) was the most affected with a 50% decrease in the effluent 12.5% plus TBT exposed group and 25% decrease in the effluent 50% plus TBT, if compared with the TBT alone. Overall, our results give further support to the use of imposex in N. lapillus as a specific biomarker of TBT contamination. However, in areas of high inputs of sewage effluents, the assessment of TBT contamination by the use of the imposex phenomenon should ideally also include data on the tissue levels of butyltins.

Combining organic photochromism with inorganic paramagnetism--optical tuning of the iron(II) electronic structure.

The crystalline photochromism of a diarylethene pyridyl ligand is applied to the modulation of the electronic environment of a high-spin Fe(II) metal ion.

Study of the effects of interferon a on several human hepatoma cell lines: analysis of the signalling pathway of the cytokine and of its effects on apoptosis and cell proliferation.

BACKGROUND: Interferon alpha (IFNalpha), currently used for the treatment of chronic viral hepatitis, is also known to prevent the development of hepatocellular carcinoma (HCC), the mechanism of this action being still debatable. AIMS: To study thoroughly in human hepatoma cell lines (HHL)--Hep3B, HepG2, HuH7, SKHep1, and Chang-Liver--submitted to rhIFNalpha, the signalling pathway of IFNalpha, the binding activity of the cytokine on specific gamma-activated sequence (GAS) and interferon-stimulated regulatory element (ISRE) nuclear sequences, and its effects on apoptosis and cell proliferation. METHODS: The behaviour of signal transducer and activator of transcription (STAT)1, STAT2, p48(IRF9) and the binding of nuclear proteins were investigated by immunoblot and electro-mobility shift assay. Expression of some IFNalpha-dependent proteins--p21/(WAF1), inducible nitric oxide synthase, IRF1 and 2--were studied by immunoblot. Apoptosis and the cell cycle were studied by morphological and biochemical methods. RESULTS: Transduction of INFalpha was unaltered, although there were some variations in the different HHL. Nuclear protein binding to GAS or ISRE showed that ISRE was mainly involved. Apoptosis did not occur. The cell cycle was slightly modified in HuH7. Three GAS- and/or ISRE-dependent proteins increased, suggesting that IFNalpha may have some biological effects on HHL. CONCLUSIONS: The IFNalpha signalling pathway is functional in several HHL, but the cytokine has no apoptotic effect and a moderate anti-proliferative effect. This suggests that the preventive role of IFNalpha on HCC cannot be explained by an apoptotic and/or an anti-proliferative effect, but possibly by its action on several specific nuclear sequences that protect liver cells from transformation.

Experimental and theoretical charge density of DL-alanyl-methionine.

X-ray diffraction data up to d = 0.50 A resolution have been collected at 100 K for a DL-alanyl-methionine single crystal using a CCD area detector. Multipolar crystallographic refinement was carried out and the electron density of the molecule has been analyzed. The deformation electron density around the S atom reveals two lone pairs with an sp(3) hybridization and agrees with the results of density functional theory calculations. The topological properties of the covalent bonds and of the hydrogen bonds have been investigated. Two weak polar intramolecular interactions of the type C(5) (pentagonal cyclic structure) have unfavorable geometrical parameters for hydrogen bonds and are devoid of critical points. The two electron lone pairs of the carbonyl oxygen appear asymmetric in the experimental deformation density. This could be attributed to the different strength of the hydrogen bond and intramolecular polar interaction involving the carbonyl oxygen. In the ab-initio-derived deformation maps, the asymmetry of the electron doublets is reproduced only very partially.