Efficacy of a new medical device based on colloidal silver and carbossimetyl beta glucan in treatment of upper airways disease in children.

AIM: Nasal congestion is the main symptom in common upper respiratory diseases in childhood. Intranasal administration of sympatheticomimetics decongestants is commonly adopted for this symptom. The Italian Drug Agency stated a warning against the use of these drugs in children under 12 years of age. The aim of this study is to evaluate the efficacy on nasal symptoms and the safety of a new medical device based on colloidal silver and carbossimetyl beta glucan compared with saline solution treatment in a group of children (0-12 years) affected by viral rhinitis. METHODS: Hundred consecutive outpatient children (0-12 year old), affected by common cold syndrome with evident nasal obstruction were randomly assigned to two type of intervention: group 1. receiving colloidal silver and carbossimetyl beta glucan; group 2. receiving saline solution. Each subject underwent clinical history and objective examination of rhinosinusal district at enrollment. Upper respiratory pathologie-related symptoms were specifically evaluated by using the Canadian Acute Respiratory Illness and Flu Scale (CARIFS). RESULTS: A significant improvement of CARIFS score was observed into the two groups. The score improvement of these two treatment was confirmed in all the age sub-group. We observed a statistically significant difference in mean post-treatment CARIFS score and CARIFS globas VAS (Visual Analogic Scale) in children of group 1 compared with children in group 2 (2.28 ± 1.58 vs. 5.08 ± 3.39; P<0.001 and VAS: 1.87 ± 1.38 vs. VAS: 3.34 ± 2.19; P=0.012, respectively). At the end of treatment, 90% of subjects in group 1 resulted completely recovered, whereas 10% experienced some degree of complications (otitis, tracheitis, bronchitis). In group 2 a complete recovering was achieved in 66 % of subjects, the remaining 34 % developed complications. Tolerability profiles were similar in the two groups with no statistical differences in side effects in all age subgroups. CONCLUSION: Despite both treatments reached significative improvements in CARIFS global score and VAS and in physical examination of nasal mucosa and secretion at the end of the therapy, colloidal silver and carbossimetyl beta glucan showed a better performance with a significant difference in mean post-treatment CARIFS global score and CARIFS VAS compared to treatment with saline solution.

Contribution of artificial neural networks to the classification and treatment of patients with uninvestigated dyspepsia.

OBJECTIVES: To verify whether symptoms reported by patients with uninvestigated dyspepsia might be helpful in either classifying functional from organic dyspepsia (1st experiment), or recognising which Helicobacter pylori infected patients may benefit from eradication therapy (2nd experiment). METHODS: We compared the performance of artificial neural networks and linear discriminant analysis in two experiments on a database including socio-demographic features, past medical history, alarming symptoms, and symptoms at presentation of 860 patients with uninvestigated dyspepsia enrolled in a large observational multi-centre Italian study. RESULTS: In the 1st experiment, the best prediction for organic disease was given by the Sine Net model (specificity of 87.6% with 13 patients misclassified) and the best prediction for functional dyspepsia by the FF Bp model (sensitivity of 83.4% with 56 patients misclassified). The highest global accuracy of linear discriminant analysis was 65.1%, with 150 patients misclassified. In the 2nd experiment, the highest predictive performance was provided by the SelfDASn model: all infected patients who became symptom-free after successful eradicating treatment were correctly classified, whereas nine errors were made in forecasting patients who did not benefit from such a therapy. The highest global performance of linear discriminant analysis was 53.2%, with 37 patients misclassified. CONCLUSIONS: In patients with uninvestigated dyspepsia, artificial neural networks might have potential for categorising those affected by either organic or functional dyspepsia, as well as for identifying all Helicobacter pylori infected dyspeptic patients who will benefit from eradication.

Structural insight into Parkinson's disease treatment from drug-inhibited DOPA decarboxylase.

DOPA decarboxylase (DDC) is responsible for the synthesis of the key neurotransmitters dopamine and serotonin via decarboxylation of L-3,4-dihydroxyphenylalanine (L-DOPA) and L-5-hydroxytryptophan, respectively. DDC has been implicated in a number of clinic disorders, including Parkinson's disease and hypertension. Peripheral inhibitors of DDC are currently used to treat these diseases. We present the crystal structures of ligand-free DDC and its complex with the anti-Parkinson drug carbiDOPA. The inhibitor is bound to the enzyme by forming a hydrazone linkage with the cofactor, and its catechol ring is deeply buried in the active site cleft. The structures provide the molecular basis for the development of new inhibitors of DDC with better pharmacological characteristics.

Familial clustering of Helicobacter pylori infection: population based study.

OBJECTIVES: To assess the rate of intrafamilial transmission of Helicobacter pylori infection in the general population and the role of a family's social background. DESIGN: Population survey. SETTING: Campogalliano, a town in northern Italy with about 5000 residents. PARTICIPANTS: 3289 residents, accounting for 416 families. MAIN OUTCOME MEASURES: Prevalence of H pylori infection assessed by presence of IgG antibodies to H pylori. RESULTS: The overall prevalence of H pylori infection was 58%. Children belonging to families with both parents infected had a significantly higher prevalence of H pylori infection (44%) than children from families with only one (30%) or no parents (21%) infected (P<0.001). Multivariate analyses confirmed that children with both parents positive had double the risk of being infected by H pylori than those from families in which both parents were negative. Family social status was independently related to infection in children, with those from blue collar or farming families showing an increased risk of infection compared with children of white collars workers (odds ratio 2.02, 95% confidence interval 1.16 to 3.49). CONCLUSIONS: H pylori infection clusters within families belonging to the same population. Social status may also be a risk factor. This suggests either a person to person transmission or a common source of exposure for H pylori infection.

Preliminary X-ray analysis of a new crystal form of recombinant pig kidney DOPA decarboxylase.

DOPA decarboxylase is responsible for the synthesis of the key neurotransmitters dopamine and serotonin via decarboxylation of L-3, 4-dihydroxyphenylalanine (L-DOPA) and L-5-hydroxytryptophan, respectively. The crystals of recombinant DOPA decarboxylase differ from those previously reported for the enzyme purified from pig kidney. They belong to space group P622 with unit-cell dimensions a = b = 302.6, c = 178.1 A. Both the self-rotation function and the good diffraction quality of these crystals (2.5 A on a synchrotron source) suggest that there should be at least three protein dimers in the asymmetric unit. Diffraction data sets have been collected for the native enzyme and a heavy-atom derivative.

Reaction of dopa decarboxylase with alpha-methyldopa leads to an oxidative deamination producing 3,4-dihydroxyphenylacetone, an active site directed affinity label.

Dopa decarboxylase (DDC) catalyzes the cleavage of alpha-methylDopa into 3,4-dihydroxyphenylacetone and ammonia, via the intermediate alpha-methyldopamine, which does not accumulate during catalysis. The ketone has been identified by high-performance liquid chromatography and mass spectroscopic analysis, and ammonia by means of glutamate dehydrogenase. Molecular oxygen is consumed during the reaction in a 1:2 molar ratio with respect to the products. The kcat and Km of this reaction were determined to be 5.68 min-1 and 45 microM, respectively. When the reaction is carried out under anaerobic conditions, alpha-methyldopamine is formed in a time-dependent manner and neither ammonia nor ketone is produced to a significant extent. The reaction is accompanied by a time- and concentration-dependent inactivation of the enzyme with kinact of 0. 012 min-1 and Ki of 39.3 microM. Free 3,4-dihydroxyphenylacetone binds to the active site of DDC and inactivates the enzyme in a time- and concentration-dependent manner with a kinact/Ki value similar to that of alpha-methylDopa. d-Dopa, a competitive inhibitor of DDC, protects the enzyme against inactivation. Taken together, these findings indicate the active site directed nature of the interaction of DDC with 3,4-dihydroxyphenylacetone and provide evidence that the ketone generated by the reaction of DDC with alpha-methylDopa dissociates from the active site before it inactivates the enzyme. Inactivation of the enzyme by ketone followed by NaB3H4 reduction and chymotryptic digestion revealed that the lysine residue which binds pyridoxal 5'-phosphate (PLP) in the native enzyme is the site of covalent modification. Together with the characterization of the adduct released from the inactivated DDC, these data suggest that the enzyme is inactivated by trapping the coenzyme in a ternary adduct with ketone and the active site lysine. As recently reported for serotonin (5-HT) [Bertoldi, M., Moore, P. S., Maras, B., Dominici, P., and Borri Voltattorni, C. (1996) J. Biol. Chem. 271, 23954-23959], the conversion of dopamine (DA) into 3,4-dihydroxyphenylacetaldehyde and ammonia catalyzed by DDC is accompanied by irreversible loss of decarboxylase activity. However, the comparison between the absorbance, fluorescence, and CD features of DDC after 5-HT- or 3, 4-dihydroxyphenylacetone-induced inactivation shows that a different covalent adduct is formed between either of these two molecules and DDC-bound PLP.

Mutation of cysteine 111 in Dopa decarboxylase leads to active site perturbation.

Cysteine 111 in Dopa decarboxylase (DDC) has been replaced by alanine or serine by site-directed mutagenesis. Compared to the wild-type enzyme, the resultant C111A and C111S mutant enzymes exhibit Kcat values of about 50% and 15%, respectively, at pH 6.8, while the K(m) values remain relatively unaltered for L-3,4-dihydroxyphenylalanine (L-Dopa) and L-5-hydroxytryptophan (L-5-HTP). While a significant decrease of the 280 nm optically active band present in the wild type is observed in mutant DDCs, their visible co-enzyme absorption and CD spectra are similar to those of the wild type. With respect to the wild type, the Cys-111-->Ala mutant displays a reduced affinity for pyridoxal 5'-phosphate (PLP), slower kinetics of reconstitution to holoenzyme, a decreased ability to anchor the external aldimine formed between D-Dopa and the bound co-enzyme, and a decreased efficiency of energy transfer between tryptophan residue(s) and reduced PLP. Values of pKa and pKb for the groups involved in catalysis were determined for the wild-type and the C111A mutant enzymes. The mutant showed a decrease in both pK values by about 1 pH unit, resulting in a shift of the pH of the maximum velocity from 7.2 (wild-type) to 6.2 (mutant). This change in maximum velocity is mirrored by a similar shift in the spectrophotometrically determined pK value of the 420-->390 nm transition of the external aldimine. These results demonstrate that the sulfhydryl group of Cys-111 is catalytically nonessential and provide strong support for previous suggestion that this residue is located at or near the PLP binding site (Dominici P, Maras B, Mei G, Borri Voltattorni C. 1991. Eur J Biochem 201:393-397). Moreover, our findings provide evidence that Cys-111 has a structural role in PLP binding and suggest that this residue is required for maintenance of proper active-site conformation.

Aromatic amino acid methyl ester analogs form quinonoidal species with Dopa decarboxylase.

This study reports for the first time that binding of aromatic methyl ester analogs to Dopa decarboxylase in the native and inactive nicked forms causes the appearance of a dead-end quinonoidal species absorbing at 500 nm, in addition to an external aldimine absorbing at 398 nm. The equilibrium mixture of these species varies depending on both the analog structure and the enzyme form. The above mentioned intermediates are also characterized with respect to their CD properties and the equilibria for their formation are determined as a function of pH. The results have provided evidence that the establishment of proper contacts between the active site and hydroxyl groups of the ligand are indispensable in order to limit unwanted side reactions.

[A quinapril-hydrochlorothiazide combination in the treatment of essential arterial hypertension]. / L'associazione quinapril/idroclorotiazide nel trattamento dell'ipertensione arteriosa essenziale.

This open, non-controlled study was planned to investigate efficacy and tolerability of fixed combination quinapril 20 mg plus hydrochlorothiazide 12.5 mg for treatment of mild-to-moderate essential hypertension. One hundred and fifty seven patients, with diastolic pressure ranging 105-119 mmHg, were enrolled after two weeks wash-out; during this period patients received placebo. After placebo phase, patients received one tablet/day of fixed combination for six weeks: at the end of this period patients were classified as "responder" (lowering of pressure = or > 10 mmHg) or "non responder"; "non responder" were planned to receive two tablets/day while "responder" maintained the former posology. Patients were reexamined after four weeks: "non responder" were dropped out while "responder" maintained the actual posology. Study was performed in fourteen weeks totally; at the end of this period fourteen patients were classified as "non responder". The fixed combination quinapril 20 mg plus hydrochlorothiazide 12.5 mg can be considered a valid drug for the treatment of mild-to-moderate hypertension.

Mechanism-based inactivation of dopa decarboxylase by serotonin.

Pig kidney dopa decarboxylase (DDC) expressed in Escherichia coli is a homodimeric enzyme containing one catalytically active pyridoxal 5'-phosphate active site per subunit. In addition to catalyzing the decarboxylation of -aromatic amino acids, DDC also reacts with 5-hydroxytryptamine (5-HT), converting it to 5-hydroxyindolacetaldehyde and ammonia. These products have been identified by means of the enzymes alcohol dehydrogenase and glutamate dehydrogenase, together with high performance liquid chromatographic and mass spectroscopic analysis. The Kcat and Km values of this reaction were determined to be 0.48 min-1 and 0.47 mM, respectively. The NaBH4-reduced enzyme does not catalyze this reaction. Concurrent with this reaction, 5-HT inactivates DDC in both a time- and concentration-dependent manner and exhibits saturation of the rate of inactivation at high concentrations, with Ki and Kinact values of 0.40 mM and 0.023 min-1, respectively. Protection from inactivation by 5-HT was observed in the presence of the active site-directed inhibitor 3,4-dihydroxy-D-phenylalanine. Inactivation with [2-14C]5-HT results in the incorporation of 1 mol of label/enzyme subunit. Taken together, these findings indicate that 5-HT is both a substrate and a mechanism-based inactivator with a partition ratio for product formation versus inactivation of 21. The absorbance, CD, and fluorometric features of 5-HT-inactivated DDC have also been characterized. A speculative mechanism for the reaction and inactivation consistent with the experimental findings is presented.

Cloning and expression of pig kidney dopa decarboxylase: comparison of the naturally occurring and recombinant enzymes.

L-Aromatic amino acid decarboxylase (dopa decarboxylase; DDC) is a pyridoxal 5'-phosphate (PLP)-dependent homodimeric enzyme that catalyses the decarboxylation of L-dopa and other L-aromatic amino acids. To advance structure-function studies with the enzyme, a cDNA that codes for the protein from pig kidney has been cloned by joining a partial cDNA obtained by library screening with a synthetic portion constructed by the annealing and extension of long oligonucleotides. The hybrid cDNA was then expressed in Escherichia coli to produce recombinant protein. During characterization of the recombinant enzyme it was unexpectedly observed that it possesses certain differences from the enzyme purified from pig kidney. Whereas the later protein binds 1 molecule of PLP per dimer, the recombinant enzyme was found to bind two molecules of coenzyme per dimer. Moreover, the Vmax was twice that of the protein purified from tissue. On addition of substrate, the absorbance changes accompanying transaldimination were likewise 2-fold greater in the recombinant enzyme. Examination of the respective apoenzymes by absorbance, CD and fluorescence spectroscopy revealed distinct differences. The recombinant apoprotein has no significant absorbance at 335 nm, unlike the pig kidney apoenzyme; in the latter case this residual absorbance is associated with a positive dichroic signal. When excited at 335 nm the pig kidney apoenzyme has a pronounced emission maximum at 385 nm, in contrast with its recombinant counterpart, which shows a weak broad emission at about 400 nm. However, the holoenzyme-apoenzyme transition did not markedly alter the respective fluorescence properties of either recombinant or pig kidney DDC when excited at 335 nm. Taken together, these findings indicate that recombinant pig kidney DDC has two active-site PLP molecules and therefore displays structural characteristics typical of PLP-dependent homodimeric enzymes. The natural enzyme contains one active-site PLP molecule whereas the remaining PLP binding site is most probably occupied by an inactive covalently bound coenzyme derivative; some speculations are made about its origin. The coenzyme absorbing bands of recombinant DDC show a modest pH dependence at 335 and 425 nm. A putative working model is presented to explain this behaviour.

Transaldimination induces coenzyme reorientation in pig kidney dopa decarboxylase.

Dopa decarboxylase from pig kidney is a pyridoxal-5'-phosphate (PLP) dependent enzyme that displays positive circular dichroism (CD) relative to the coenzyme absorption bands at 335 and 420 nm, which are characteristic of an asymmetrically bound coenzyme. It has been previously noted that the presence of various substrates and substrate analogs gives rise to similar absorbance changes, independently of whether or not the enzyme-ligand interaction is accompanied by the conversion of the internal aldimine to an external aldimine. The effects of various ligands on the CD spectral properties of the enzyme bound PLP are presented herein. It was observed that changes in the optical activity are seen only in the presence of ligands capable of Schiff base formation. These results imply that a reorientation of the pyridoxal phosphate ring occurs upon formation of an external aldimine. Moreover, external aldimines formed with catecholic and indolic compounds are characterized by quite dissimilar optical activities, suggesting that with respect to vicinal residues, different coenzyme microenvironments exist in these complexes.

Dissociation, unfolding and refolding trials of pig kidney 3,4-dihydroxyphenylalanine (dopa) decarboxylase.

The effect of guanidinium chloride (GuCl) on enzyme activity, hydrodynamic volume, circular dichroism, and fluorescence of 3,4-dihydroxyphenylalanine (Dopa) decarboxylase from pig kidney (pkDDC) was studied under equilibrium conditions. Unfolding proceeds in at least three stages. The first transition, occurring between 0 and 1 M GuCl, gives rise to a dimeric inactive species which has lost pyridoxal 5'-phosphate (PLP), and has a high tendency to aggregate, but retains almost all of the native spectroscopic characteristics. The second equilibrium transition, between 1 and 2.2 M GuCl, involves dimer dissociation, with some loss of tertiary and secondary structure. Additionally, gross conformational changes at or near the PLP microenvironment were detected by fluorescence of NaBH4-reduced enzyme. The third step, presumably representing complete unfolding of pkDDC, appears to be complete at 4.5 M GuCl, as indicated by the lack of further substantial changes in any of the signals being studied. Attempts at refolding resulted in the findings that: (1) partial reactivation is observed only starting from enzyme denatured at concentrations below 1.5 M GuCl, and (2) starting from completely denatured protein, the refolding process is apparently reversible down to concentrations of approx. 2 M GuCl. Taken together, this would seem to indicate that the monomer-dimer transition is impaired under the experimental conditions tested. A plausible model is presented for the unfolding/refolding of pkDDC.

Modified purification of L-aromatic amino acid decarboxylase from pig kidney.

A new protocol for purification of L-aromatic amino acid decarboxylase from pig kidney in which, after an initial ultracentrifugation, only two columns are required to obtain homogeneous enzyme is presented. The protocol provides protein with a higher specific activity than that previously obtained, reducing by about one-half the time required for purification.

Crystallization and preliminary X-ray analysis of pig kidney DOPA decarboxylase.

DOPA decarboxylase from pig kidney, an alpha 2 dimeric enzyme of Mr = 107,000, has been crystallized by the vapour diffusion method with ammonium sulphate as precipitant. The crystals belong to the space group P6(2) (or its enantiomer P6(4)) and have unit cell dimensions of a = b = 155.9 A, c = 87.7 A, alpha = beta = 90 degrees, gamma = 120 degrees. They diffract to 2.6 A resolution. There is one dimeric molecule per asymmetric unit. Rotation function studies have revealed the orientation of the non-crystallographic 2-fold axis of the dimer in the asymmetric unit.

Pig kidney 3,4-dihydroxyphenylalanine (dopa) decarboxylase. Primary structure and relationships to other amino acid decarboxylases.

The complete amino acid sequence of pig kidney 3,4-dihydroxyphenylalanine (Dopa) decarboxylase is reported. The sequence was determined from analysis of peptides isolated after tryptic and cyanogen bromide cleavages of the enzyme. Each subunit is made up of 485 residues, corresponding to a molecular mass of 53858 Da. The N-terminus of the polypeptide chain is an acetylated methionyl residue. A number of structural features, previously shown to be important for the structure and function of the enzyme, could be localized along the polypeptide chain. Comparison of the primary structure with the known cDNA-deduced sequences of other Dopa decarboxylases (i.e. the human, bovine, rat, guinea-pig and Drosophila enzymes) reveals 50% identity. The identity increases to 73%, if the comparison is restricted to the mammalian sequences. Comparison with other aromatic and non-aromatic decarboxylases allows some consideration to be made in terms of structure/function and evolutionary relationships in this class of enzymes.

Affinity labeling of pig kidney 3,4-dihydroxyphenylalanine (Dopa) decarboxylase with N-(bromoacetyl)pyridoxamine 5'-phosphate. Modification of an active-site cysteine.

Pig kidney 3,4-dihydroxyphenylalanine (Dopa) decarboxylase is inactivated by N-(bromoacetyl)pyridoxamine 5'-phosphate (BAPMP) in a reaction which follows first-order kinetics at pH 7.5 and 25 degrees C. The concentration dependence of inactivation reveals saturation kinetics with an apparent Ki of 0.16 mM and kinact of 0.086 min-1 at saturating inhibitor concentration. Enzyme can be protected from inactivation by pyridoxal 5'-phosphate. Inactivation of enzyme by [14C]BAPMP proceeds with the incorporation of a stoichiometric amount of labeled inhibitor. Proteolytic digestions of the radioactively labeled enzyme followed by high-performance liquid chromatography allow the isolation of the modified peptide corresponding to the sequence Ala-Ala-Ser-Pro-Ala-Cys-Thr-Glu-Leu in which cysteine (Cys111) is the modified residue. The conservation of this residue and also of an extended region around it in all Dopa decarboxylases so far sequenced is underlined. The overall conclusion of these findings is that Cys111 may be at, or near, the pyridoxal-5'-phosphate binding site of pig kidney Dopa decarboxylase and plays a critical role in the catalytic function of the enzyme. Furthermore, fluorescence studies of BAPMP-modified apoenzyme provide useful information on the microenvironment of the affinity label at its binding site.

A clinical and neurophysiological trial on nootropic drugs in patients with mental decline.

The different expressions of mental decline in elderly people, from simple senile benign forgetfulness to SDAT, can be evaluated by psychometric and neurophysiological tests. In the present study, the effects of oxiracetam, piracetam and placebo were compared in a group of elderly subjects. The results of the trial, structured as single blind, clearly showed that nootropics positively effect both clinical and neurophysiological performances and that oxiracetam produces a more pronounced effect when compared to piracetam. In fact, oxiracetam was found more effective in improving psychometric scales such as GDS (clinical performances) as well as the amplitude and the latency of the P300 (neurophysiological performances), which reflect a functional recovery of the cerebral pathways related to attention and memory.