Cyclolinopeptide A (CLA) mediates its immunosuppressive activity through cyclophilin-dependent calcineurin inactivation

The immunosuppressive cyclic nonapeptide cyclolinopeptide A inhibits calcium-dependent, but not calcium-independent, activation of T lymphocytes comparably to the actions of cyclosporin A and FK506. The concentration required for complete inhibition, however, is 10 times higher than that of cyclosporin A. In addition, we demonstrate that calcineurin, a phosphatase which plays an important role in T lymphocyte signalling, is inhibited in vitro by cyclolinopeptide A by a mechanism dependent on the peptidyl-prolyl cis-trans isomerase (PPIase) cyclophilin A but not FKBP12. Direct binding of cyclolinopeptide A to cyclophilin A was confirmed using tryptophan fluorescence studies and PPIase assays. These results represent a third example of the production of a natural product that neutralises calcineurin by a mechanism dependent on the primary binding to a PPIase.     

8-HYDROXY-2'DEOXYGUANOSINE LEVELS AND ANTIOXIDANT STATUS IN RAT LIVER FED WITH OLIVE AND CORN OIL DIETS: EFFECT OF ASCORBIC ACID SUPPLEMENATION

DNA damage and antioxidants status were determined in liver of rat fed with olive and corn oil diets with and without ascorbic acid supplementation. In order to elucidate the role of fat intake, the study included a control and hyperlipidic diet. Liver antioxidant activities were significantly influenced by dietary fat and intake levels. In general, control groups fed with corn oil diets exhibited reduced liver antioxidant (SOD, catalase, and GSH-PX) and GSH levels compared with rats fed on olive oil diets. These activities were lower in rats consuming hyperlipidic diets relative to the control groups. Ascorbic acid supplementation resulted in a slight decrease of antioxidant activities both in the control and hyperlipidic diets with the exception of GSH that showed high levels in rats fed on an olive oil diet supplemented with ascorbic acid. The results of oxidative DNA damage as measured by the induction of 8-hydroxy deoxyguanosine (8-OHdG) clearly confirmed that corn diet (rich in polyunsaturated fatty acids) induced DNA damage in a dose- dependent manner. No induction of 8-OHdG was detected for the diet containing olive oil (monounsaturated diet). Ascorbic acid had no effect on rat fed on an olive oil diet. In contrast, for corn diets the ascorbic acid showed     

Bioactivity of human growth hormone in serum: validation of an in vitro bioassay

GH, in clinical practice, is determined by RIA, but RIA estimates may not accurately reflect serum GH bioactivity. The available measures of GH bioactivity lack either sensitivity, specificity, or a physiologically relevant end point. The objective of this research was to develop a physiologically relevant GH bioassay which would not only measure the bioactivity of purified GH preparations, but would also have sufficient sensitivity to measure GH bioactivity in human serum. The method consisted of incubating murine 3T3-F442A adipocytes in serum-free medium containing BSA, 14C-glucose, and increasing concentrations of GH or test materials for 24 h, followed by measurement of conversion of glucose to lipid. Interference by nonspecific serum factors was reduced by the addition of 10 micrograms/liter insulin, 25 nM dexamethasone, and 37 nM estradiol to the medium. In the presence of 10 micrograms/liter insulin, 50 micrograms/liter insulin-like growth factor-1 did not alter the ability of GH to suppress lipid accumulation. Epinephrine and glucagon could suppress lipid accumulation but only at concentrations greatly in excess of the physiological range in serum. Twenty two thousand dalton hGH produced dose-dependent suppression of lipid accumulation which was linear between 0.625 and 10 micrograms/liter (r = 0.926; P = 0.0001) with a half-maximal response of 3.0 +/- 0.2 micrograms/liter (n = six experiments). The intra- and interassay coefficients of variation were 7% and 19%, respectively. The assay was specific for GH since addition of human PRL produced suppression of lipid accumulation only at concentrations where contamination of the preparation by GH became a significant factor. ACTH also suppressed lipid accumulation but only at doses of 1000 micrograms/liter or greater. Human placental lactogen and hLH, hFSH, and hTSH did not cross-react with GH in this assay. Addition of human serum did not alter the slope of ED50 of the GH dose-response curve. Pools of serum from prepubertal and pubertal boys and girls, subjects treated with arginine or insulin, a diabetic girl, and a boy with gigantism who had a serum GH content of 80 micrograms/liter by RIA and 40 micrograms/liter by bioassay, produced dose response curves parallel to that of the GH standard curve. Serum from patients with hypopituitarism did not produce significant suppression of lipid accumulation in any assay. Recovery of 5 micrograms/liter GH added to human serum was 94%. Twenty thousand dalton GH also suppressed lipid accumulation in this assay, but was 2-fold less potent than 22,000 dalton GH.(ABSTRACT TRUNCATED AT 400 WORDS)     

Suppression of tuftsin activity by the partial sequences of adenovirus type 2 proteins

OBJECTIVE: This study follows the sequential changes in anti-lipopolysaccharide antibodies in infected patients with and without septic shock. SUMMARY BACKGROUND DATA: A relation between high endogenous levels of anti-LPS antibodies and protection against bacteremia and septic shock in at-risk patient groups has been observed. However, information on the daily follow-up and kinetics of apparition or disappearance of anti-LPS antibody activities and their relations with the protective properties of the different immunoglobulin classes has not been clearly investigated. METHODS: Two hundred and five septic surgical patients were studied during their stay in the intensive care unit during a period of 3 years. Among these patients, septic shock developed in 54 and 47 died. A sensitive ELISA was used to study circulating IgM and IgG antibodies to the core glycolipid (CGL) region of Salmonella minnesota R595. The activities were measured each day when sepsis occurred and every hour during septic shock. RESULTS: Anti-CGL IgM activity was found in 32% of the septic patients. This response, however, most often appeared to be transient. A strong correlation was observed between the occurrence of septic shock and the absence of anti-CGL IgM activity on admission to the ICU (p < 0.02). Anti-CGL IgG activity was detected in 82% of the patients and better correlated with outcome for patients with high or rising activities during their hospitalization (p < 0.0005). In patients with septic shock or irreversible organ failure, a fall in the anti-CGL IgG activity was observed before death, suggesting that the IgG antibodies were consumed during this acute event. Therefore, the anti-CGL IgG activity measured by ELISA could be used as a marker of the evolution of the illness. CONCLUSIONS: Our observations demonstrate the interest to follow-up the evolution of the anti-CGL antibodies during sepsis. The fall of these antibodies during septic shock and in patients who died was an additional argument to perform, as an additive form, passive antibody therapy to decrease lethality in this group of patients.     

Dark current suppression in HOT LWIR HgCdTe heterostructures operating in non-equilibrium mode

Typically,infrared detectors require cryogenic cooling to limit dark current w hich is directly dependent on Auger generation-recombination mechanism and highly influential in Hg Cd Te-narrow band gap material.The Auger suppressed architectures have an advantage over conventional detectors allow ing operation at elevated temperatures200 K.Architecture w ith combination of exclusion and extraction heterojunctions has been proposed to low er Auger contribution.The paper presents a new long-w ave(≈10μm)infrared Hg Cd Te architecture w ith graded gap/doping interfaces and extra barrier located in exclusion heterojunction to suppress dark current for high operating temperature conditions.Proper barrier implementation reduces dark current by more than 20 A/cm2for room temperature operation.     

Oculoplethysmography. Evaluation of patients with transient ischemic attacks from internal carotid artery disease

Oculoplethysmography was used to evaluate 66 patients with transient ischemic attacks prior to cerebral angiography. Fifty-eight (87.9%) symptomatic internal carotid arteries had anatomically significant stenosis. Only 69 per cent of these 58 arteries had positive OPG test. Thirty-one per cent of the arteries were well compensated hemodynamically with collaterals and had a false negative test. A negative OPG test does not rule out an anatomically significant internal carotid artery stenosis.     

Peptides related to FKBP 39-45 loop possess immunostimulative potency

Taking into account the sequential homology existing between thymopoietin II, the DNA-binding domain of p53 protein and FKBP (FK-506 binding protein), a series of fragments of human and bovine FKBP containing a fragment Ser39-Pro45 were synthesized. In the humoral in vitro test all the peptides act as stimulators. Whereas in the in vivo test peptides derived from bovine FKBP show an immunostimulative and those from human FKBP an immunosuppressive activity. However, after blocking the Asp residue by a Bzl group the peptide V appears to be an immunostimulator. The data obtained suggest that these peptides can influence the immune system by blocking the FKBP receptor.