Morpho-functional modifications of human neutrophils induced by aqueous cigarette smoke extract: comparison with chemiluminescence activity.

Cigarette smoking plays an important role as a cause of morbidity and mortality in humans, involving respiratory, cardiovascular, digestive and reproductive systems. Tobacco smoke contains a large number of molecules, some of which are proven carcinogens. Although not fully understood, polymorphonuclear leukocytes seem to play a crucial role in the mechanisms by which tobacco smoke compounds are implicated in smoke-related diseases. In this paper the effects of an aqueous cigarette smoke extract on the expression of adhesion molecules of polymorphonuclear leukocytes together with the changes in the cell morphology have been related to the chemiluminescence activity. The results obtained show that polymorphonuclear leukocytes treated with aqueous cigarette smoke extract are significantly impaired, as suggested by the changes of chemiluminescence activity, of membrane receptors (CD18, CD62), myeloperoxidase expression and of cell morphology. Altogether the present data indicate that treated polymorphonuclear leukocytes are ineffectively activated and therefore unable to phagocytize zymosan particles.

New developments in anthracycline-induced cardiotoxicity.

Anthracyclines are among the most effective anticancer drugs ever developed. Unfortunately, their clinical use is severely limited by the development of a progressive dose-dependent cardiomyopathy that irreversibly evolves toward congestive heart failure, usually refractory to conventional therapy. The pathophysiology of anthracycline-induced cardiomyopathy remains controversial and incompletely understood. The current thinking is that anthracyclines are toxic per se but gain further cardiotoxicity after one-electron reduction with ROS overproduction or two-electron reduction with conversion to C-13 alcohol metabolites. ROS overproduction can probably be held responsible for anthracycline acute cardiotoxicity, but not for all the aspects of progressive cardiomyopathy. Intramyocardial formation of secondary alcohol metabolites might play a key role in promoting the progression of cardiotoxicity toward end-stage cardiomyopathy and congestive heart failure. In this review we also discuss recent developments in: a) the molecular mechanisms underlying anthracycline-induced cardiotoxicity; b) the role of cytosolic NADPH-dependent reductases in anthracycline metabolism; c) the influence of genetic polymorphisms on cardiotoxicity outcome; d) the perspectives on the most promising strategies for limiting or preventing anthracycline-induced cardiotoxicity, focusing on controversial aspects and on recent data regarding analogues of the natural compounds, tumor-targeted formulations and cardioprotective agents.

Oxygen transport in extreme environments.

Evolution has adopted different strategies to solve the problem of transporting oxygen to respiring tissues, according to needs dictated by the environment. A thermodynamic analysis of haemoglobins of organisms living in extreme polar environments (mammals and fish) provides elegant examples of such adaptations.

Band 3 protein function in teleost fish erythrocytes: effect of oxygenation-deoxygenation.

During vertebrate evolution, structural changes in red blood cells (RBC) and hemoglobin (Hb), have probably resulted in the importance of blood carbon dioxide transport. The chloride/bicarbonate exchange across the RBC membrane, which is an integral part of the blood CO(2) transport process in vertebrates, has been examined on two different species of teleost fish, Euthynnus alletteratus and Thunnus thynnus, at several oxygenation states of erythrocyte HOS (high-oxygenation state, about 90 % of saturation) and LOS (low-oxygenation state, about 15 % of saturation). The results were compared with those observed in human RBC under the same experimental conditions and with the chicken (Gallus gallus) erythrocytes, which have particular modifications at the N-terminus of the band 3 protein (B3). In fish the kinetic measurements have shown a different anion transport in several oxygenation states of erythrocytes, indicating that also at lower levels of vertebrate evolution there exists a modulation of the anionic flow affected by oxygen. The functional correlation of anion transport to changes of parts of the hemoglobin sequence responsible for alterations in the interactions with the cytoplasmic domain of band 3 protein (cdb3) allowed us to suggest a hypothesis about fish physiology. The highest values of kinetic measurements observed in fish have been attributed to the metabolic need of the RBC in response to the removal of CO(2) that in teleosts is also of endogenous origin.

Influence of gemfibrozil on sulfate transport in human erythrocytes during the oxygenation-deoxygenation cycle.

The effects of gemfibrozil (GFZ), an antihyperlipidemic agent, on the anionic transport of the human red blood cells (RBC) during the oxygenation-deoxygenation cycle were examined. Gemfibrozil clearly plays a role in the modulation of the anionic flux in erythrocytes; in fact it causes a strong increment of anions transport when the RBCs are in the high-oxygenation state (HOS). Such an effect is remarkably reduced in the low-oxygenation state (LOS). With the aim of identifying the dynamics of fibrate action, this effect has been investigated also in human ghost and chicken erythrocytes. These latter, in fact, are known to possess a B3 (anion transporter or Band 3) modified at the cytoplasmic domain (cdb3) which plays a significant role in the metabolic modulation of red blood cells. The results were analyzed taking into account the well-known interactions between fibrates and both conformational states of hemoglobin i.e. the T state (deoxy-conformation) and the R state (oxy-conformation). The effect of gemfibrozil on anionic influx appears to be due to a wide interaction involving a "multimeric" Hb-GFZ-cdb3 macromolecular complex.

Different structural behaviors evidenced in thaumatin-like proteins: a spectroscopic study.

Three proteins belonging to the thaumatin-like proteins family were compared in this study from a structural point of view: zeamatin, a new recently isolated PR-5 from Cassia didymobotrya and the commercial sweet-thaumatin. The former two proteins possess antifungal activities while commercial thaumatin is well known to be a natural sweetener. Intrinsic fluorescence studies have evidenced that the three proteins behave differently in unfolding experiments showing different structural rigidity. All the three proteins are more stable at slight acidic buffers, but sweet-thaumatin has a major tendency to destructurate itself. Similar observations were made from circular dichroism studies where a structural dependence relationship from the pH and the solvent used confirmed a hierarchic scale of stability for the three proteins. These structural differences should be considered to be significant for a functional role.

Salivary thiols and enzyme markers of cell damage in periodontal disease.

OBJECTIVES: Recent studies describe the potential use of biochemical markers in the evaluation of the severity of periodontitis; moreover, patients suffering from periodontitis frequently complain of halitosis (breath malodour), mainly depending on volatile compounds (e.g. hydrogen sulphide, methyl mercaptan, etc.) produced by anaerobic metabolism of oral bacteria and involving sulphur-containing amino acids. In this study, salivary sulphur compounds, such as cysteine, cysteinylglycine and glutathione and some markers of cellular damage (lactate dehydrogenase and aspartate amino transferase), were measured in periodontitis patients and correlated with the periodontal probing pocket's depth. DESIGN AND METHODS: Twenty-two periodontitis patients and forty control subjects were studied for the salivary activities of lactate dehydrogenase and aspartate aminotransferase and cysteine, cysteinylglycine and glutathione concentrations. The periodontitis patients were divided into two subgroups based on the severity of periodontal disease, expressed as median periodontal probing pocket depth (> or <5 mm). Enzyme activities were measured by using an automated clinical analyzer; cysteine, cysteinylglycine and glutathione concentrations were measured by HPLC equipped with fluorescence detector. RESULTS: A statistically significant increase of the salivary parameters level (cysteine, cysteinylglycine, glutathione, aspartate aminotransferase and lactate dehydrogenase) was found in the patient subgroup with periodontal probing pocket depth >5 mm, the salivary cysteine concentrations showing the most significant correlation. CONCLUSIONS: Salivary cysteine, a direct precursor of hydrogen sulphide, could be considered reliable markers for the oral tissue damage severity in periodontitis patients.

Alterations of energy metabolism and glutathione levels of HL-60 cells induced by methacrylates present in composite resins.

OBJECTIVES: Methacrylic compounds such as 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA) and bisphenol A glycerolate (1 glycerol/phenol) dimethacrylate (Bis-GMA) are largely present in auto- or photopolymerizable composite resins. Since the polymerization reaction is never complete, these molecules are released into the oral cavity tissues and biological fluids where they could cause local adverse effects. The aim of this work was to verify the hypothesis that the biological effects of HEMA, TEGDMA and Bis-GMA - at a non-cytotoxic concentration - depend on the interaction with mitochondria and exert consequent alterations of energy metabolism, GSH levels and the related pathways in human promyelocytic cell line (HL-60). METHODS: The biological effects of methacrylic monomers were determined by analyzing the following parameters: GSH concentration, glucose-6-phosphate dehydrogenase (G6PDH) and glutathione reductase (GR) activity, oxygen and glucose consumption and lactate production along with cell differentiation and proliferation. RESULTS: All monomers induced both cellular differentiation and decrease in oxygen consumption. Cells treated with TEGDMA and Bis-GMA showed a significant enhancement of glucose consumption and lactate production. TEGDMA and HEMA induced GSH depletion stimulating G6PDH and GR activity. CONCLUSIONS: All the monomers under study affect the metabolism of HL-60 cells and show differentiating activity. Since alterations in cellular metabolism occurred at compound concentrations well below cytotoxic levels, the changes in energy metabolism and glutathione redox balance could be considered as potential mechanisms for inducing clinical and sub-clinical adverse effects and thus providing useful parameters when testing biocompatibility of dental materials.

Slight association between type 1 diabetes and "ff" VDR FokI genotype in patients from the Italian Lazio Region. Lack of association with diabetes complications.

BACKGROUND: Vitamin D receptor (VDR) mediates the effects of vitamin D. Our paper evaluates the FokI and BsmI VDR genotypes in 246 Caucasian (Italian from Lazio Region) T1DM patients compared with 246 Caucasian healthy controls, sharing age and gender and regional provenience with the patients. In addition, T1DM patients without complications were compared with those carrying three complications. METHODS: Genotyping has been obtained by RFLP-PCR technique. RESULTS: A slight significant association of T1DM with FokI homozygous "f" genotype was observed. No association was observed with the presence of multiple complications by a multivariate analysis. CONCLUSION: T1DM patients showed slightly increased prevalence of "ff" VDR genotype.

Protective effect of rhubarb derivatives on amyloid beta (1-42) peptide-induced apoptosis in IMR-32 cells: a case of nutrigenomic.

Amyloid beta (1-42) peptide is considered responsible for the formation of senile plaques that accumulate in the brains of patients with Alzheimer's disease (AD). In the last years considerable attention has been focused on identifying natural food products, such as phytochemicals that prevent or almost retard the appearance of amyloid beta (1-42)-related neurotoxic effects. In this study, human neuroblastoma cells (IMR-32) was used as system model to evaluate the protective role of rhaponticin (3,3',5-trihydroxy-4'-methoxystilbene 3-O-d-glucoside) a stilbene glucoside extracted from rhubarb roots (Rhei rhizoma) and rhapontigenin, its aglycone metabolite, against amyloid beta (1-42)-dependent toxicity. The obtained results show that rhapontigenin maintains significant cell viability in a dose-dependent manner and it exerts a protective effect on mitochondrial functionality, as evidenced by mitochondrial oxygen consumption experiments. A similar behaviour, but to a lesser extent, has been shown by rhaponticin. The protective mechanism mediated by the two stilbenes could be related to their effect on bcl-2 gene family expression. Bax, a pro-apoptotic gene, resulted down-regulated by the treatment with rhaponticin and rhapontigenin compared with the results obtained in the presence of amyloid beta (1-42) peptide. Conversely, bcl-2, an anti-apoptotic gene, highly down-regulated by amyloid beta (1-42) treatment, resulted expressed in the presence of stilbenes similarly to that shown by control cells. The obtained results support the hypothesis that amyloid beta (1-42)-induced neurotoxicity occurs via bax over-expression, bcl-2 down-regulation, firstly indicating that rhaponticin and its aglycone moiety may alter this cell death pathway. Based on these studies, we suggest that rhaponticin and its main metabolite could be developed as agents for the management of AD.

Purification and characterization of an antifungal thaumatin-like protein from Cassia didymobotrya cell culture.

A 23-kDa antifungal thaumatin-like protein was isolated and purified from Cassia didymobotrya (Fres.) cell cultures for the first time. The protein was secreted in the culture medium, but it could be also isolated after elution of whole cells with a 0.5 M CaCl(2) solution. Treatment of the cells with laminarin oligosaccharides or salicylic acid, but not with NaCl, resulted in enhancement of expression of the protein. A rapid purification protocol was used based on cationic exchange chromatography. The protein, with a highly basic character (pI 10), has an exact molecular mass of 23034 Da, as determined by MALDI-ToF mass spectrometry analysis. N-terminal sequencing of the intact polypeptide and the sequencing of two internal tryptic peptides indicated significant identity with other thaumatin-like proteins (TLP). The protein exerted antifungal activity towards some Candida species showing EC(50) values comparable to those of other antifungal TLPs. The collected data lead to classify this TLP as a new PR-5 protein.

Increased levels of IGF-1 and beta2-microglobulin in epithelial lining fluid of preterm newborns developing chronic lung disease. effects of rhG-CSF.

UNLABELLED: Insulin-like growth factor-1 (IGF-1) is involved in regulating the Th-1/Th-2 balance, favoring the development of the Th-2 compartment which enhances fibrosis, one of the main characteristics of Chronic Lung Disease (CLD) in premature newborns. Limited data is available concerning a possible association between early epithelial lining fluid (ELF) concentrations of IGF-1 (total and free forms), IGF-binding protein-3 (IGFBP-3), beta2-microglobulin and subsequent development of CLD in preterm neonates. If neutropenic, preterm neonates are frequently treated with recombinant human granulocyte colony stimulating factor (rhG-CSF). The objective of the study was to correlate ELF concentrations of IGF-1 and beta2 microglobulin during the first week of life both in non-neutropenic and in rhGCSF-treated neutropenic preterm neonates, with subsequent development in CLD. Thirty preterm neonates with Respiratory Distress Syndrome (6 with neutropenia) were studied. Eleven out of 24 non-neutropenic preterm infants (46%) and all of the six neutropenic subjects (100%) developed CLD. With the exception of first day values, there was a clear similarity in the behaviors of assayed molecules between non-neutropenic and neutropenic patients developing CLD. Non-neutropenic patients without CLD showed significantly lower values of free IGF-1 and beta2M both on days 1 and 3. Total IGF-I and cell counts were different only on the 3rd day. CONCLUSIONS: 1) the mechanisms leading to CLD might be mediated by high levels of IGF-family molecules soon after birth 2) beta2M could be a marker of increased bronchoalveolar lavage fluid cellularity with potential inflammatory properties 3) G-CSF treatment induces an increased synthesis of IGF-1 molecules by cells recruited in the lung, with possible enhancement of the fibrogenic mechanisms.

In vitro comparison of the cytotoxicity of two orthodontic composite resins.

AIM: Several studies have reported that dental resin-based materials release substances with biological activity: for this reason in this study we evaluated the in vitro cytopathic effects of a self-curing and a light-curing orthodontic composite resins by a cytotoxicity test. METHODS: The cytotoxic potential of specimens, prepared according to the manufacturer instructions, was evaluated using the thiazolyl blue tetrazolium bromide (MTT) assay on the mouse fibroblast cell line (3T3 Swiss) with 2 cells-material contact systems: the 24 h extracts method and the indirect toxicity method. RESULTS: The results obtained in this study elicit a close agreement between the 2 procedures; from the data obtained in the reported experimental conditions, it was possible to establish that the examined chemical-cured material is more cytotoxic than the light-cured one. CONCLUSIONS: From a clinical point of view, the photo-polymerizable resins are undoubtedly more useful in the daily practice, because of the larger precision of the bonding obtainable by the greater period available for setting the brackets before their lock. The results obtained in this study, even considering the limits of the in vitro tests, represent a further favourable feature of the light-curing composite resins. However, further investigations about the influence of polymerization methods of the materials on the biological effects are suggested to contribute to the determination of the best clinical operative conditions.

Properties of hemoglobin G. Ferrara (beta57(E1) Asn replaced by Lys).

Hemoglobin G. Ferrara is an abnormal human hemoglobin in which an asparagine residue is replaced by a lysyl residue at position beta57 (beta57 Asn replaced by Lys). Oxygen equilibria show that cooperativity and alkaline Bohr effect are maintained to normal levels while the acid Bohr effect appears increased; in addition, a smaller effect of diphosphoglycerate is also observed. Flash photolysis experiments performed as a function of protein concentration show that the fraction of quickly reacting form is always higher than that of human hemoglobin A. This fact, together with the increase of the oxygen affinity observed at acid pH values, may be related to an enhanced dissociation of the molecule into dimers. Several attempts to isolate the native chains by treatment of the protein with p-chloromercuribenzoate were unsuccessful due to the great instability of the isolated variant beta-chains, which precipitated completely during incubation with p-chloromercuribenzoate. Therefore, although the substitution is on the surface of the molecule, there are several properties of hemoglobin G. beta Ferrara which are clearly different from hemoglobin A.

Functional properties of partially oxidized trout hemoglobins.

This paper reports on a study of the effect of partial oxidation on oxygen and carbon monoxide binding by components I and IV of trout hemoglobin. The O2 binding equilibria of the various oxidation mixtures show a decrease in the heme-heme interactions as the number of oxidized sites is increased. However, the large Bohr effect, characteristic of Hb Trout IV, is maintained unchanged. Similarly the time course of CO combination changes on increasing the fractional oxidation, and the autocatalytic character of the CO binding kinetics is lost; however the pH dependence of the apparent "on" constant in the oxidation mixtures is similar to that characteristic of the native molecule. The results of the O2 equilibria and of CO binding kinetics may be interpreted in accordance with the two state concerted model suggesting that in the oxidation intermediates there is an increase in the fraction of the high affinity (R) conformation. Additional experiments on the effect of azide, and fluoride, ferric ligands which produce a change of spin state of the heme iron, suggest that additional second order conformational changes may also come into play.

Properties of trout hemoglobin covalently bound to a solid matrix.

This paper reports the ligand binding properties of the major hemoglobin component from trout (Salmo irideus) covalently bound to a solid matrix (Sepharose or Sephadex). A comparison between the functional properties of this protein in solution and of the protein-matrix complex shows significant changes although the basic properties of the molecule are maintained on covalent binding to Sepharose (or Sephadex). Thus the Root effect, characteristic of Hb trout IV, is still present while the heme-heme interactions are, on the average, smaller in the matrix bound protein as compared to the soluble form. No differences in the O2 binding properties were observed when the protein was coupled to the resin, as the ligand bound or as the ligand free derivative. Although an unequivocal interpretation of the data is made difficult by the lack of information on the number and identity of the groups involved in the coupling, the main changes in the protein functional properties may be related to the chemical modifications "per se" more than to the immobilization imposed to the macromolecule by coupling to the matrix. Structural changes which mainly involve perturbation of the tertiary structure of the molecule may qualitatively rationalize the data.

Reduced sensitivity of O2 transport to allosteric effectors and temperature in loggerhead sea turtle hemoglobin: functional and spectroscopic study.

The functional and spectroscopic (EPR and absorbance) properties of the adult loggerhead sea turtle (Caretta caretta) hemoglobin have been studied with special reference to the action of allosteric effectors and temperature. Present results indicate that turtle Hb displays a very low O2 affinity and a very small sensitivity to allosteric effectors and temperature. Furthermore, the amplitude of the Bohr effect for O2 binding is strongly reduced. In parallel, EPR and absorbance spectroscopic properties of the nitrosylated derivative of turtle Hb suggest that the hemoprotein is in a low-affinity conformation, even in the absence of allosteric effectors. These findings suggest the existence of unusual molecular mechanisms modulating the basic reaction of Hb with O2, which may be linked to specific physiological needs related to the diving behavior of the turtle.

The primary structure of hemoglobin from reindeer (Rangifer tarandus tarandus) and its functional implications.

The primary structures of alpha- and beta-chains of hemoglobin from reindeer (Rangifer tarandus tarandus) were determined. Comparison of the reindeer hemoglobin sequence with those of human and bovine hemoglobins showed 50 and 29 substitutions per alpha beta dimer, respectively. The influence of replacements on the modulation of hemoglobin oxygen affinity by heterothopic ligands and temperature, as well as their importance on the structure-function relationships in hemoglobin are discussed.

Mini-myoglobin: native-like folding of the NO-derivative.

Mini-myoglobin is a polypeptide fragment (residues 32-139) obtained by limited proteolysis of horse heart apomyoglobin and reconstituted with the natural heme. Its functional properties are very similar to those of native myoglobin and therefore it may represent a model for testing the functional role of the protein fragment encoded by the central exon of myoglobin gene (residues 31-105). Here we have investigated some properties of the nitric oxide derivative of mini-myoglobin in comparison with those of NO-myoglobin, to provide more structural information on the heme pocket residues in addition to that already acquired by electron paramagnetic resonance of the cobalt-substituted mini-myoglobin. At pH 7.0, optical and circular dichroism Soret spectra, as well as electron paramagnetic resonance spectra reveal that the heme orientation in the pocket and the coordination state of the ferrous iron in NO-mini-myoglobin are similar to those of the whole protein. The spectra of the NO-mini-myoglobin complex are very sensitive to pH changes at variance to what is observed for the NO-myoglobin derivative in the same pH range (5.5-9.5). In particular, increasing or decreasing pH from 7.0, results in a decrease of the extinction coefficient and of the ellipticity in the Soret region and in a change of the shape of the electron paramagnetic resonance signal. The spectral changes are diagnostic for a transition from a hexa-coordinated (at pH 7.0) to a penta-coordinated heme (at pH 5.5 or 9.5), with the proximal histidine-iron bond either broken or stretched dramatically. Thus, although mini-myoglobin is able to bind NO in a geometry similar to that of the native protein, the resulting NO derivative shows a much higher pH dependence, suggesting that the two lacking side domains are mainly involved in enhancing the stability of the hemoprotein core.

Physicochemical and functional properties of Perinereis cultrifera (Grübe) erythrocruorin.

Perinereis erythrocruorin has the following physicochemical properties: So20,w = 55S, corresponding to a molecular weight around 2.7-10(6); minimum molecular weight (on the basis of the heme content) 23 700 +/- 500; isoelectric point 5.1; alpha-helix content approximately 40%. At alkaline pH values in the oxygenated form the 55-S molecules dissociate into subunits with a weight average sedimentation coefficient of 3S, corresponding to a molecular weight approximately 35 000. Deoxygenation of partially dissociated samples promotes association of the 3-S subunits into a 9S component. The functional properties of Perinereis erythrocruorin are characterized by a low cooperativity in oxygen binding (n 1/2 = 1.5) at neutral pH. Cooperativity increases reversibly towards both the acid and alkaline pH range, irrespective of changes in molecular weight. This finding, taken together with the ultracentrifuge results, suggests that a subunit may represent the functional unit of the protein. The pH dependence of the oxygen affinity can be accounted for in terms of a single oxygen linked group with a pK of 8.