A specific prediction equation is necessary to estimate peak oxygen uptake in obese patients with metabolic syndrome.

PURPOSE: The aims were to: (1) compare peak oxygen uptake ([Formula: see text]peak) predicted from four standard equations to actual [Formula: see text]peak measured from a cardiopulmonary exercise test (CPET) in obese patients with metabolic syndrome (MetS), and (2) develop a new equation to accurately estimate [Formula: see text]peak in obese women with MetS. METHODS: Seventy-five obese patients with MetS performed a CPET. Anthropometric data were also collected for each participant. [Formula: see text]peak was predicted from four prediction equations (from Riddle et al., Hansen et al., Wasserman et al. or Gläser et al.) and then compared with the actual [Formula: see text]peak measured during the CPET. The accuracy of the predictions was determined with the Bland-Altman method. When accuracy was low, a new prediction equation including anthropometric variables was proposed. RESULTS: [Formula: see text]peak predicted from the equation of Wasserman et al. was not significantly different from actual [Formula: see text]peak in women. Moreover, a significant correlation was found between the predicted and actual values (p < 0.001, r = 0.69). In men, no significant difference was noted between actual [Formula: see text]peak and [Formula: see text]peak predicted from the prediction equation of Gläser et al., and these two values were also correlated (p = 0.03, r = 0.44). However, the LoA95% was wide, whatever the prediction equation or gender. Regression analysis suggested a new prediction equation derived from age and height for obese women with MetS. CONCLUSIONS: The methods of Wasserman et al. and Gläser et al. are valid to predict [Formula: see text]peak in obese women and men with MetS, respectively. However, the accuracy of the predictions was low for both methods. Consequently, a new prediction equation including age and height was developed for obese women with MetS. However, new prediction equation remains to develop in obese men with MetS.

[An atypical presentation of atherosclerosis in psoriasis: "Porcelain aorta"]. / Présentation particulière de l'athérome au cours du psoriasis : un cas d'« aorte porcelaine ¼.

BACKGROUND: Several recent epidemiological studies have shown an increase in cardiovascular morbidity and mortality in patients with psoriasis; such increase is greater in the event of severe and early psoriasis. PATIENTS AND METHODS: We report the case of a 42-year-old patient with severe skin psoriasis ongoing since childhood and presenting with porcelain aorta, a little-known sign of atherosclerosis. This is the first publication reporting this association. DISCUSSION: Porcelain aorta results from atherosclerotic calcification of the aortic arch. For long asymptomatic, it can manifest itself in various complications. This observation highlights the importance of cardiovascular risk assessment and of screening for complications thereof in patients presenting psoriasis.

Clinical characteristics and outcomes of COMPASS eligible patients in France. An analysis from the REACH Registry.

BACKGROUND: Following the publication of the COMPASS trial, the European Medicines Agency has approved a regimen of combination of rivaroxaban 2.5mg twice daily and a daily dose of 75-100mg acetylsalicylic acid (ASA) for patients with coronary artery disease (CAD) or symptomatic peripheral artery disease (PAD) at high risk of ischemic events. However, the applicability of such a therapeutic strategy in France is currently unknown. AIMS: To describe the proportion of patients eligible to COMPASS in France, their baseline clinical characteristics and the rate of major adverse cardiovascular events, using the REACH registry. METHODS: From the the REduction of Atherothrombosis for Continued Health (REACH) registry database, a large international registry of patients with, or at risk, of atherothrombosis, we analyzed patients included in France with either established CAD and/or PAD and fulfilling the inclusion and exclusion criteria of the COMPASS trial. The ischemic outcome was a composite of cardiovascular (CV) death, myocardial infarction (MI), or stroke, and serious bleeding were defined as haemorrhagic stroke or bleeding leading to hospitalization or transfusion. RESULTS: Among more than 65000 patients enrolled in REACH, 2.012 patients were evaluable and enrolled in France. Among them, 1194 patients (59.3%) were eligible to COMPASS. The main reasons for exclusion of the COMPASS trial, were high bleeding risk (59.1%), anticoagulant use (43.4%), requirement for dual antiplatelet therapy within 1 year of an ACS or PCI (24.7%). In the "COMPASS eligible population", the rate of MACE (CV, MI and stroke) at 4 years follow-up was 13.4% [11.3-15.8], and serious bleeding was 2.5% at 4 years [1.6-3.4]. Patients with polyvascular disease (n=219) had the highest rate of MACE, compared with patients with CAD only and PAD only (19.1% [13.9-26.1] vs. 11.6% [9.1-14.8] vs 13.2% [9.2-18.8], P<0.0001, respectively). CONCLUSION: The COMPASS therapeutic strategy in France appears to be applicable to more than half of CAD or PAD patients. This population appears at high residual risk of atherothrombotic events, and patients with polyvascular disease experienced the highest rate of events.

Different functions are required for initiation and maintenance of immortalization of rat embryo fibroblasts by SV40 large T antigen.

We have used two different, but complementary assays to characterize functions of SV40 T antigen that are necessary for its ability to immortalize rat embryo fibroblasts. In accordance with previous work, we found that several functions were required. These include activities that map to the p53 binding domain and the amino terminal 176 amino acids which contain the J domain as well as the CR1 and CR2 domain required for binding and sequestering the RB family of pocket proteins. Moreover, we found that even though activities dependent only upon the amino terminus were sufficient for immortalization they were unable to maintain it. This suggests that immortalization by these amino terminal functions requires either additional events or immortalization of a subset of cells within the heterogeneous rat embryo fibroblast population. We further found that an activity dependent upon amino acids 17 - 27 which remove a portion of the CR1 domain and the predicted alpha-1 helix of the J domain was not necessary to maintain growth but was required for direct immortalization suggesting that at least one of the functions required initially was not required to maintain the immortal state. This represents the first demonstration that some of the functions required for maintenance of the immortal state differ from those required for initiation of immortalization.

New approaches for the reconstitution and functional assay of membrane transport proteins. Application to the anion transporter of human erythrocytes.

The human red blood cell anion transport protein, band 3, was isolated and reconstituted into lipid vesicles. The main feature of the new reconstitution is the replacement of native lipids and of solubilizing detergent by externally added lipids, while band 3 protein is immobilized on a gel matrix. The vesicles formed upon detergent removal and sonication are unilamellar and sealed, and band 3 protein is the major polypeptide detectable in them. The method consists of: (a) solubilization of alkali-treated red blood cell membranes by Triton X-100; (b) binding of glycophorin and band 3 protein to diethylaminoethyl (DEAE)-cellulose in Triton X-100 solution, followed by high ionic strength elution; (c) band 3 protein complexation to organomercurial Sepharose; (d) exchange of the Triton X-100 with the dialyzable detergent octylglucopyranoside, while band 3 protein is complexed to the column; (e) elution of band 3 by cysteine (5 mM) in the presence of octylglucopyranoside; (f) addition of lipids (asolectin or egg phosphatidylcholine) to the protein-detergent suspension; and (g) dialysis of the mixture against 1% bovine serum albumin to remove the detergent completely. The vesicles were assayed for anion transport capacity by a novel procedure which is based on the fluorescent substrate N-(2-aminoethylsulfonate)7-nitrobenz-2-oxa-1,3-diazole (NBD-taurine) and on anti-NBD-antibodies as quenchers of extravesicular NBD-taurine fluorescence. Efflux of NBD-taurine from vesicles was monitored in a continuous mode as a decrease in intravesicular fluorescence. The band 3-mediated flux was approx. 50% inhibitable by externally added disulfonic stilbenes, indicating the random distribution of band 3 protein in reconstituted vesicles. Both the specific transfer rate (i.e., nmol substrate/mg protein per min) of band 3 and its energy of activation (Ea) in the artificial lipid milieu were similar to those obtained with the native system. Glycophorin incorporation into this milieu had no significant effect on the associated anion transport properties.

L is for lytic granules: lysosomes that kill.

CTL are important cells in the immune system which are able to recognise and directly destroy virally infected, tumorigenic or foreign cells. The proteins which mediate this destruction are packaged into specialised secretory granules, termed lytic granules, which are secreted in response to target cell recognition. Curiously these specialised secretory granules also contain all the lysosomal hydrolases, and in CTL the lytic granules serve two separate functions: as a lysosome within the cell, and as a secretory granule when a target cell is recognised. These "secretory lysosomes", which serve important roles in both protein degradation within the cells as well as regulated secretion of proteins from the cells, are also found in other cell types, all of which are derived from the hemopoietic lineage. This observation raises the possibility that cells of the hemopoietic lineage possess specialised sorting and secretory mechanisms which allow the lysosomes to be used as secretory organelles. Studies on Chediak Higashi syndrome support this idea, since in this naturally occurring genetic mutation, cells with secretory lysosomes are unable to secrete their granules while other conventional secretory cells are able to do so. Further studies on the mechanisms which regulate secretion of lytic proteins from CTL should identify the proteins involved in this unusual secretory pathway. Some aspects of the differences between conventional and "secretory" lysosomes remain unresolved. How the biogenesis of the secretory lysosome differs from that of a conventional secretory granule is unclear. While conventional secretory cells sort proteins destined for the granule by a selective condensation in the TGN, the secretory lysosomes seem to use a combination of lysosomal and other sorting signals. Our preliminary studies suggest that haemopoietic cells possess specialised sorting mechanisms which allow the correct sorting of the secreted products to the lysosome, and that these signals are different from those found in conventional secretory (e.g. neurosecretory) cells. This finding and the observation that fibroblast lysosomes can undergo calcium-mediated exocytosis suggests that the unusual secretory system found in haemopoietic cells may be a result of specialised sorting mechanisms in these cells. In this case the Chediak lesion may turn out to be a sorting defect.

Orientation of transmembrane polypeptides as revealed by antibody quenching of fluorescence.

We describe here a new method, based on fluorescent techniques, for the determination of the orientation of membrane protein molecules present in vesicles. The method consists of: (a) attachment of a fluorescein derivative to sugar residues of glycoproteins and glycolipids in the cell membrane, and (b) the use of anti-fluorescein antibody, a highly efficient quencher of fluorescein fluorescence, for the quantitative evaluation of sidedness of transmembrane orientation of protein molecules in vesicles. Since antibody molecules do not permeate membranes, quenching is limited exclusively to sites exposed at the external surface of the vesicles. Addition of antibody to a fluorescently-labeled cell suspension results in a full and immediate quenching of the fluorescent signal. The method is highly sensitive (pM protein concentration), rapid and readily applicable to various vesicle preparations. With this method we assessed the orientation of vesicles derived from red blood cell membranes (ghosts) in isotonic medium and followed their inversion from right-side-out to inside-out orientation upon incubation in alkaline, low ionic strength medium.

Oriented reconstitution of red cell membrane proteins and assessment of their transmembrane disposition by immunoquenching of fluorescence.

The two major membrane glycoproteins of human red cells, glycophorin and band 3, the anion exchange protein, were isolated from cells exofacially labeled with fluorescein and reconstituted into vesicles with defined transmembrane disposition. Uniform orientation of polypeptides was accomplished by two procedures: Vesicles with single protein units were obtained by a one-step dilution of a protein/detergent suspension with a vast excess of phospholipid. Vesicles with uniform orientation of protein were selected by affinity chromatography on derivatized Sepharoses (organomercurial, wheat germ agglutinin, aminoethyl or diethylaminoethyl). Vesicles with multiple protein units with uniform orientation were generated by vectorial immobilization of detergent solubilized proteins on the above affinity matrices and in situ formation of proteoliposomes by detergent substitution for phospholipid. The proteoliposomes were released from the column by addition of excess free ligand. The orientation of band 3 and glycophorin in the reconstituted vesicles was first assessed by immunofluorescence quenching, using anti-fluorescein antibodies, to quantitatively quench fluorescein residues exposed on the outer surface of vesicles. Further assessment was achieved by chromatographing the vesicles through various affinity and ionic matrices. Vesicle populations of higher than 90% homogeneity in protein orientation (right-side-out or inside-out) were obtained with both procedures. The above methods provide a convenient experimental tool for the oriented reconstitution of proteins and the evaluation of their transmembrane disposition.

Proteases and cell-mediated cytotoxicity.

Cytotoxic T lymphocytes and natural killer cells represent the body's primary defense against viral-infected and tumorigenic cells. The classically described mechanism by which these cells induce target cell death is granule mediated: cytolytic granules within the killer cell are directionally exocytozed toward the target cell, and the granule contents inflict a "lethal hit" on the target cell. A second mechanism of cytotoxicity is now known to exist, and utilizes cell surface receptors on the target cell, for which the ligand is expressed on the killer cell. Receptor oligomerization results in the recruitment of cytoplasmic proteins to the receptors and the transduction of a death signal to the target cell. In both granule- and receptor-mediated cytotoxicity, the target cell dies through a defined series of steps, which together are termed apoptosis. Recent work on apoptosis has defined a family of cysteine proteases, the caspases, which appear to be involved in the initiation of apoptosis in response to a number of stimuli. This review focuses on studies that link these proteases to target cell death induced by cytotoxic cells.

Brain and testis selective expression of the glutathione S-transferase Yb3 subunit is governed by tandem direct repeat octamer motifs in the 5'-flanking region of its gene.

To gain insight into mechanisms of cell type-specific transcription of class mu-glutathione S-transferase genes, the gene encoding the Yb3 subunit was cloned. Yb3 subunits are selectively expressed at high levels in rat brain and testis but not in liver or kidney. The Yb3 subunit gene spans over 6 kb and consists of 8 exons and 7 introns and a sequence consisting of tandem direct repeat consensus octamer DNA binding motifs separated by a 6 base pair (bp) spacer was identified in its 5'-flanking region. Gel shift assays with a 40 bp segment of DNA containing the two consensus octamer sequences, revealed the presence of specific binding proteins in nuclear extracts of rat brain, testis and C6 glioma cells. DNA binding activity was greatly reduced in liver, kidney and HTC cells. Reporter vectors carrying segments of the 5'-flanking region of the Yb3 subunit gene fused to a luciferase gene were introduced into C6 glioma cells which express high levels of Yb3 subunits, and into HTC cells which do not. The plasmids consisting of the Yb3 gene promoter up to, but not including, the octamer motifs did not support luciferase transcription in the C6 glioma cells, but larger fragments that included the octamer repeat sequences, effectively directed transcription in the C6 glioma cells. With mutated octameric sequences transcriptional activity was greatly reduced, and none of the same Yb3 constructs directed substantial luciferase transcription in the HTC cells. The results show that octamer motifs in the 5'-flanking region of the Yb3 subunit gene are functional and are the principal cis-acting elements that account for its discrete cell type-selective expression. This gene is one of the few known targets for octamer DNA binding transcription factors in brain.

[Posture and gait modulation using sensory or attentional cues in Parkinson's disease. A possible approach to the mechanism of episodic freezing]. / Modulation de la posture et de la marche par des facteurs sensoriels ou attentionnels chez le parkinsonien. Une approche possible du mécanisme des épisodes de freezing.

Parkinsonian patients have difficulties for walking as well as for adapting their posture following a voluntary or automatic movement that will disturb their equilibrium. Furthermore, in Parkinson's disease, the patients can suffer for motor blockades (or freezing) in which the movement is like frozen during its execution. These motor blockades can occur during gait initiation, turning round, as well as during the walking through apertures or small passages, but with a high variability as inter-individual as intra-individual. Cognitive, attentional or sensory stimulation--especially visual information--can interact directly on these motor blockades, either positively inhibiting them or negatively inducing them. The different modulation factors of locomotion as well as posture, in Parkinsonian patient and in healthy elderly, and the special case of the motor blockades in Parkinsonian patients are reviewed here. We also examine the effects of L-DOPA with respect to each of these factors. In the conclusion, the modulation of gait, posture, and freezing are discussed in term of mechanisms involved or hypothesis recently proposed.

The makings of a water crisis.

PIP: Globally, almost all of the water is salty, with only 2.5% being freshwater. Two-thirds of this freshwater is stored in glaciers and permanent snow cover, while one-third consists of groundwater, which is more or less accessible. In 1995, consumption of water reached 2300 cu. km, most of which went to agriculture, industries, and municipalities. The demand for freshwater has more than doubled since the start of the century and the yearly per capita potential availability of renewable freshwater has been declining steadily. At the same time, the proportion of available but polluted water continuously increases, particularly because of changes in the modes of industrial and agricultural production and increasing urbanization. In quantifying freshwater scarcity, the use of the ¿water stress index¿ (the ratio of water withdrawal to water availability) is a conservative estimation of water shortage. Almost all of the developing countries are experiencing scarcity of water resources, and importation of stocks, desalinization, and the use of nonrenewable water resources are deemed necessary. Population growth, economic development, and limitation on the financial and technical know-how further exacerbate this situation. With the existing serious water problems facing one-third of the population, it can be expected that the proportion would most probably double by 2025 if the trends continue.^ieng

BAP37 and Prohibitin are specifically recognized by an SV40 T antigen antibody.

We have identified two cellular proteins that are specifically immunoprecipitated by an anti-SV40 T antigen monoclonal antibody. This antibody, PAb419, recognizes an epitope contained within a region of T antigen which we have recently demonstrated is required for the initiation of immortalization by SV40 T antigen, but is not essential for maintenance of the immortal state. The two proteins were identified as BAP37 and Prohibitin. Recent results suggest Prohibitin may enhance the transcriptional inactivation of E2F by the retinoblastoma family of pocket proteins (pRb, p107, p130). BAP37 and Prohibitin are specifically recognized by PAb419 and PAb210, another anti-SV40 T antigen monoclonal antibody, which has an overlapping epitope, but not by other anti-SV40 T antigen monoclonal antibodies, demonstrating the specificity of the interaction.

An interleukin-1beta converting enzyme-like protease is a key component of Fas-mediated apoptosis.

Cytotoxic T lymphocytes (CTLs) are able to kill target cells bearing foreign antigen through two distinct mechanisms: granule- and Fas-mediated cytotoxicity. The exact events involved in the induction of target cell apoptosis remain elusive, but research indicates a role for members of the interleukin-1beta converting enzyme (ICE)/Ced-3 family of cysteine proteases. The exact nature of the protease(s) involved is yet to be determined. Here we use activity assays and peptide inhibitors of ICE/Ced-3 proteases to study their role in Fas-mediated killing. We find that while certain inhibitors block DNA fragmentation and chromium release, others do not. Most notably, potent inhibitors of CPP32 and ICE could not inhibit DNA fragmentation during all cases of Fas-mediated cytotoxicity although an "ICE" inhibitor could suppress 51Cr release. Additionally, we find that CPP32 is not cleaved in all target cells during Fas killing. Although ICE activity (as measured by a fluorogenic substrate) is present in cell lysates from anti-Fas-treated cells, we found no pro-IL-1beta-cleaving activity in these lysates. Taken together, our results suggest that an alternate pathway to DNA fragmentation exists, which does not involve CPP32 activity, and that CPP32 and ICE activities are not essential to Fas-mediated killing.

Determination of betaxolol enantiomers by high-performance liquid chromatography. Application to pharmacokinetic studies.

A high-performance liquid chromatographic (HPLC) method is described for the determination of (R)- and (S)-enantiomers of betaxolol in blood and other biological fluids. Separation of the enantiomers is performed after preparation of diastereomeric derivatives with the chiral reagent R(-)-naphthylethylisocyanate by reversed-phase HPLC. Fluorimetric detection allows the quantification of betaxolol enantiomers down to 0.5 ng/ml. This method was used to evaluate the pharmacokinetic profile of the betaxolol enantiomers in three subjects following one single oral dose (20 mg) of racemic betaxolol. No significant difference was observed in blood levels of the isomers.

Activation of the apoptotic protease CPP32 by cytotoxic T-cell-derived granzyme B.

Cytotoxic T lymphocyte (CTL)-mediated cytotoxicity represents the body's major defence against virus-infected and tumorigenic cells, and contributes to transplant rejection and autoimmune disease. During killing, CTL granules are exocytosed, releasing their contents into the intercellular space between the target cell and the effector. Perforin facilitates the entry of cytotoxic cell serine proteases, the granzymes, into the target cell, where they induce apoptotic death by an unknown pathway. Granzyme B is essential for the induction of DNA fragmentation and apoptosis in target cells, yet its substrate is unknown. Identification of the intracellular substrate for granzyme B is therefore the key to understanding the mechanism of CTL-mediated killing. Here we show that granzyme B cleaves and activates CPP32, the precursor of the protease responsible for cleavage of poly(ADP-ribose) polymerase.

Cleavage of CPP32 by granzyme B represents a critical role for granzyme B in the induction of target cell DNA fragmentation.

Cytotoxic T lymphocytes (CTLs) are able to recognize and destroy target cells bearing foreign antigen using one of two distinct mechanisms: granule- or Fas-mediated cytotoxicity. The exact mechanisms involved in the induction of apoptotic cell death remain elusive; however, it seems likely that a family of cysteine proteases related to interleukin-1beta converting enzyme are involved. One family member, CPP32, has been identified as an intracellular substrate for granzyme B, a CTL-specific serine protease responsible for the early induction of target cell DNA fragmentation. Here we use cytolytic cells from granzyme B-deficient mice to confirm that cleavage and activation of CPP32 represents a nonredundant role for granzyme B and that this activation plays a role in the induction of DNA fragmentation in target cells, a signature event for apoptotic cell death. A peptide inhibitor of CPP32-like proteases confirmed the function of these enzymes in fragmentation. 51Cr release was not suppressed under these conditions, suggesting that granzyme B cleavage of CPP32 is primarily involved in the induction of DNA fragmentation and not membrane damage during CTL-induced apoptosis.