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Biomedical subjects

A Zanella

Publications and source records attributed to A Zanella.

At least 19 recordsLinked to original sources
PubMed2006

Chemical and biological characterization of dissolved organic matter from silver fir and beech forest soils.

Despite a growing attention to the dissolved organic matter (DOM) in terrestrial ecosystems and evidence of the fact that vegetation affects the quality of both undissolved and dissolved organic matter in soil, the role of DOM as a biological indicator is still poorly understood. In this work, the fertility of 59 sites, divided into eight key alliances of the order Fagetalia sylvaticae Pawl., was studied considering chemical and biological parameters such as soil DOM, hormone-like activity, low-molecular-weight (LMW) aliphatic and phenolic acids, and floristic data. Both non-parametric tests and principal component analysis (PCA) revealed differences between silver fir and beech forests and within each type of forest. There were also differences between neutrophilous and acidophilous types. What's more, PCA reveals the dominance of the auxin (IAA)-like activity, and of some phenolic acids in distinguishing the acidophilous beeches (ACI) form the other types, whereas the gibberellin (GA)-like activity is more relevant in neutrophilous conditions such as thermophilous (THE) and mesophilous (MESO) beeches and montane (MO), high montane (HMA), high montane (HMC) silver fir forests. The GA-like activity is also related to the succinic, fumaric, malonic, and l-malic acids in the MO, HMA and HMC silver fir forests. Moreover, the role of LMW aliphatic acids in mobilizing the hormone-like activity, which improves forest growth, is stressed. The growth of seedlings of Picea abies was influenced by the phenolic acid content. At concentrations between 1 and 100 microM, phenylacetic and protocatechuic acids inhibited root growth to the same extent as indoleacetic acid, while p-hydroxybenzoic acid had a stimulating effect comparable to that of gibberellic acid. The aliphatic and phenolic acids appear to be related to plant strategies that influence soil fertility affecting plant growth through rhizodeposition. The role of LMW aliphatic and phenolic acids as molecular markers of ecosystem function is noted.

Abies↗
PubMed2005

Interlaboratory comparison of red-cell ATP, 2,3-diphosphoglycerate and haemolysis measurements.

BACKGROUND AND OBJECTIVES: Red blood cell (RBC) storage systems are licensed based on their ability to prevent haemolysis and maintain RBC 24-h in vivo recovery. Preclinical testing includes measurement of RBC ATP as a surrogate for recovery, 2,3-diphosphoglycerate (DPG) as a surrogate for oxygen affinity, and free haemoglobin, which is indicative of red cell lysis. The reproducibility of RBC ATP, DPG and haemolysis measurements between centres was investigated. MATERIALS AND METHODS: Five, 4-day-old leucoreduced AS-1 RBC units were pooled, aliquotted and shipped on ice to 14 laboratories in the USA and European Union (EU). Each laboratory was to sample the bag twice on day 7 and measure RBC ATP, DPG, haemoglobin and haemolysis levels in triplicate on each sample. The variability of results was assessed by using coefficients of variation (CV) and analysis of variance. RESULTS: Measurements were highly reproducible at the individual sites. Between sites, the CV was 16% for ATP, 35% for DPG, 2% for total haemoglobin and 54% for haemolysis. For ATP and total haemoglobin, 94 and 80% of the variance in measurements was contributed by differences between sites, and more than 80% of the variance for DPG and haemolysis measurements came from markedly discordant results from three sites and one site, respectively. In descending order, mathematical errors, unvalidated analytical methods, a lack of shared standards and fluid handling errors contributed to the variability in measurements from different sites. CONCLUSIONS: While the methods used by laboratories engaged in RBC storage system clinical trials demonstrated good precision, differences in results between laboratories may hinder comparative analysis. Efforts to improve performance should focus on developing robust methods, especially for measuring RBC ATP.

2,3-Diphosphoglycerate↗
PubMed2004

Randomized, double-blind, phase III, controlled trial comparing levobupivacaine 0.25%, ropivacaine 0.25% and bupivacaine 0.25% by the caudal route in children.

BACKGROUND: The rationale for replacing racemic bupivacaine with the s-enantiomers levobupivacaine and ropivacaine is to provide a wider margin of safety with the same analgesic efficacy and less postoperative motor block. In a randomized, double-blind, phase III, controlled trial we compared the caudal administration of levobupivacaine 0.25% and ropivacaine 0.25% with bupivacaine 0.25% in children. METHODS: Ninety-nine ASA I-II children less than 10 yr old scheduled for elective sub-umbilical surgery were randomized to receive caudal block with bupivacaine 0.25%, ropivacaine 0.25% or levobupivacaine 0.25%. The primary outcome of the study was the clinical efficacy of the caudal block during the operation. Secondary outcome measures were analgesic onset time, pain relief after the operation and residual motor blockade. RESULTS: The proportion of children with effective analgesia during the operation was similar among groups. There were no significant differences in the analgesic onset time of the caudal block. Bupivacaine produced a significant incidence of residual motor block compared with levobupivacaine or ropivacaine at wake-up (P<0.01). There were no significant differences in the number of patients receiving rescue analgesia after surgery. However, analgesic block lasted significantly longer in patients receiving bupivacaine (P=0.03). CONCLUSION: During sub-umbilical surgery, caudal levobupivacaine, ropivacaine and bupivacaine provided comparable analgesic efficacy. Bupivacaine produced a higher incidence of residual motor blockade and a longer analgesic block than ropivacaine and levobupivacaine.

Abdomen↗
PubMed2004

Immunoregulatory cytokine polymorphisms in Italian patients affected by paroxysmal nocturnal haemoglobinuria and aplastic anaemia.

We investigated regulatory variants of five cytokine genes [tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, transforming growth factor (TGF)-beta, interleukin (IL)-6 and IL-10] in 40 Italian patients affected by paroxysmal nocturnal haemoglobinuria (PNH) and aplastic anaemia (AA). Genotypes associated with high production of TGF-beta and IFN-gamma were more frequent in patients than in controls. Genetic regulation of the immunological pathways involved in the pathogenesis of bone marrow failure is suggested.

Anemia, Aplastic↗
PubMed2003

A prospective study of blood alpha-fetoprotein messenger RNA as a predictor of hepatocellular carcinoma in patients with cirrhosis.

Blood alpha-fetoprotein messenger RNA (AFP mRNA) is thought to be a marker of hepatocellular carcinoma (HCC). Its value as a predictor of HCC in patients at risk is not known. A series of 201 patients with compensated cirrhosis (114 men, mean age 58 years) underwent surveillance with semi-annual ultrasound and serum alpha-fetoprotein measurements. Total RNA was extracted from peripheral blood mononuclear cells collected at different intervals and AFP mRNA was retrotranscribed and amplified by nested polymerase chain reaction. Ten patients with HCC and 30 blood donors were used as controls. Three patients with HCC, 39 with cirrhosis under surveillance and four blood donors circulated AFP mRNA (30, 20 and 13%, NS). During 50 months of surveillance, 27 patients with cirrhosis developed HCC: the tumour was detected more often in patients with higher than normal baseline serum AFP (> or =7 IU/L) than in those with normal AFP levels (21%vs 9%, P = 0.02). The incidence of HCC was the same in patients with and without AFP mRNA at baseline (15%vs 14%). In 53 patients, AFP mRNA was re-tested after 6-25 months of surveillance. HCC developed in two of 11 (18%) who were initially AFP mRNA positive and later became negative, in none of those who were initially negative and later became positive and in two of 39 (5%) who remained persistently negative. In conclusion, blood AFP mRNA is not a sensitive predictor of HCC in patients with compensated cirrhosis.

Aged↗
PubMed2003

Avian influenza attributable to serovar H7N1 in light layers in Italy.

In March 1999 a syndrome characterized by depression, anorexia, fever, and respiratory and enteric signs appeared in many flocks of turkeys and, to a lesser extent, chickens in the densely populated poultry-rearing regions of Northeastern Italy. Initially the disease was characterized by sinusitis, tracheitis, peritonitis, and pancreatitis. The responsible agent was identified as low-pathogenicity (LP) avian influenza (AI) of H7N1 subtype. Concerning the light layers, the mortality was variable, from 1.7% to 9.5%, whereas egg production decreased by 10% to 40%. According to the epidemiologic data, chickens seemed to be less sensitive to the virus than were turkeys. Nine months later, the AI virus changed to a highly pathogenic (HP) AI virus and affected, besides turkeys, a great number of pullet and layer flocks, with high mortality (80%-100%) in a few days. However, the course of disease was more prolonged in pullets. Within 3 1/2 mo, over 100 outbreaks were reported. Following the HPAI outbreaks, in late 2000 and early 2001, LPAI reemerged, but only one flock of layers was affected.

Animals↗
PubMed2002

In vitro production of anti-RBC antibodies and cytokines in chronic lymphocytic leukemia.

B-chronic lymphocytic leukemia (B-CLL) patients have a high prevalence of autoimmune phenomena, mainly autoimmune hemolytic anemia (AIHA). Immunoregulatory cytokines play a role in the regulation of both autoimmunity and leukemic B-cell growth. Mitogen-stimulated direct antiglobulin test (MS-DAT) is a recently described test able to disclose latent anti-RBC autoimmunity in AIHA. We investigated the prevalence of anti-RBC autoimmunity by MS-DAT and the pattern of cytokine production by PHA-stimulated whole blood cultures from 69 B-CLL patients and 53 controls. Results showed that anti-RBC IgG values in unstimulated, PHA-, PMA-, and PWM-stimulated cultures were significantly higher in B-CLL patients compared with controls. In B-CLL, the prevalence of anti-RBC autoimmunity was 28.9% by MS-DAT, compared with 4.3% by the standard DAT. Production of IFN-gamma, IL-2, IL-13, TNF-alpha, sCD23, and sCD30 was significantly increased in all B-CLL patients compared with controls, whereas there was no difference in IL-4, IL-6, IL-10, and TGF-beta production. Multivariate analysis showed that IL-4 was significantly increased in MS-DAT-positive compared with -negative patients. Patients with autoantibody positivity displayed greater IFN-gamma production than negative patients. These data are in line with the hypothesis that autoimmune phenomena in B-CLL are associated with an imbalance towards a Th-2-like profile. The elevated prevalence of anti-RBC autoimmunity found by MS-DAT suggests that an underestimated latent autoimmunity exists in B-CLL.

Adult↗
PubMed2001

Human erythrocyte pyruvate kinase: characterization of the recombinant enzyme and a mutant form (R510Q) causing nonspherocytic hemolytic anemia.

Human erythrocyte pyruvate kinase plays an important role in erythrocyte metabolism. Mutation on the gene results in pyruvate kinase deficiency and is an important cause of hereditary nonspherocytic hemolytic anemia. Because of difficulties in isolating the mutant enzymes from patients, these mutations have not been fully studied. In this study, a complementary DNA (cDNA) encoding the human erythrocyte pyruvate kinase was generated. The cDNA was cloned into several expression vectors, and the protein was expressed and purified. The tetrameric protein exhibited properties characteristic of authentic human erythrocyte pyruvate kinase, including response to substrate, phosphoenolpyruvate, activation by fructose 1,6-bisphosphate, and inhibition by adenosine triphosphate (ATP). The N-terminal segment of the protein was highly susceptible to proteolysis, but only 2 of the 4 subunits were cleaved and lacked 47 N-terminal amino acid residues. A mutant protein, R510Q, which is the most frequently occurring mutation among Northern European population, was also generated and purified. The mutant protein retained its binding capacity to and could be activated by fructose 1,6-bisphosphate and showed similar kinetics toward phosphoenolpyruvate and adenosine diphosphate as for the wild-type enzyme. Conversely, the mutant protein has a dramatically decreased stability toward heat and is more susceptible to ATP inhibition. The enzyme instability decreases the enzyme level in the cell, accounting for the clinically observed "pyruvate kinase deficiency" of patients who are homozygous for this mutation. This study provides the first detailed functional characterization of human erythrocyte pyruvate kinase. These findings will allow the establishment of a fine correlation between molecular abnormalities and the clinical expression of the disease.

Adenosine Triphosphate↗
PubMed2001

Cell age-related monovalent cations content and density changes in stored human erythrocytes.

Conversion of erythrocyte membrane protein 4.1b to 4.1a occurs through a non-enzymatic deamidation reaction in most mammalian erythrocytes, with an in vivo half-life of approximately 41 days, making the 4.1a/4.1b ratio a useful index of red cell age [Inaba and Maede, Biochim. Biophys. Acta 944 (1988) 256-264]. Normal human erythrocytes distribute into subpopulations of increasing cell density and cell age when centrifuged in polyarabinogalactan density gradients. We have observed that, when erythrocytes were stored at 4 degrees C under standard blood bank conditions, the deamidation was virtually undetectable, as cells maintained the 4.1a/4.1b ratio they displayed at the onset of storage. By measuring the 4.1a/4.1b values in subpopulations of cells of different density at various time points during storage, a modification of the normal 'cell age/cell density' relationship was observed, as erythrocytes were affected by changes in cell volume in an age-dependent manner. This may stem from a different impact of storage on the imbalance of monovalent cations, Na(+) and K(+), in young and old erythrocytes, related to their different complement of cation transporters.

Blood Banks↗
PubMed2001

A method to obtain right-side-out and sealed plasma membrane vesicles from the filamentous fungus Penicillium simplicissimum.

Plasma membrane vesicles were purified from the citrate excreting filamentous fungus Penicillium simplicissimum. The hyphae were disrupted by grinding in a glass bead mill and plasma membranes were obtained from a crude membrane fraction by partitioning in an aqueous dextran/polyethylene glycol two-phase system. The resulting enriched plasma membrane fraction contained only minor contaminations of marker enzymes of intracellular membranes, consisted of more than 90% of right-side-out vesicles and was sealed for potassium.

Cell Fractionation↗
PubMed2001

Evaluation of dosed red blood cell units collected with Gambro BCT--TRIMA.

The increasing need of collecting high quality blood components and of improving the overall productivity of a blood centre requires the utilisation of a new innovative process that combines high speed collection with an automated process and blood component tailoring to fit individual patient requirements. We collected dosed Red Blood Cell (dRBC) units on 64 donors, eligible as regular donors on the Gambro BCT TRIMA using the dRBC collection protocol. The collection target was set to 180 ml packed Red Blood Cells (pRBCs) in 225 ml total collection volume (n = 7), or 300 ml pRBCs in 375 ml total collection volume (n = 33) or 360 ml in 450 ml (n = 24), depending on donor's hematological profile and blood volemia. Saline was infused as the replacement fluid at a 120%) collection:infusion ratio. Donor per cent hematocrit was (mean +/- S.D.) 43.7 +/- 4.0% and TBV = 4.99 +/- 0.69 1. The procedures yielded 100 +/- 6% of predicted yield, with a hematocrit of 78.2 +/- 6.6% in 29 +/- 3 min. Hb content was 99.9 +/- 21.8 in all procedures, or 61.5-94.4-118.6 g in the three groups, respectively. After the addition of the SAG-M storage solution, the hematocrit was 56.3 +/- 6.2%. No adverse reactions have been reported by the donors and all pPRBC units were transfused to patients without any transfusion reaction being reported by clinicians. The dRBC protocol is well tolerated by donors without any side effects, other than normal effects of regular blood donation. Higher pRBC productivity can be reached with a safe and automated process in conjunction with a high and consistent product quality easily matching the donor collection criteria and pRBC unit standards. Tailoring of pRBC units can result in an improved patient transfusion support.

Blood Component Removal↗
PubMed2001

Cellular contamination of plasma collected with various apheresis systems.

Efforts to improve the purity of blood products have mainly focused on reducing white blood cell (WBC) levels in cellular blood products. Relatively little attention has been given to the cellular purity of plasma. We evaluated plasma units collected on six apheresis systems: Dideco Excel, Haemonetics-MCS+, Fresenius-AS-Tech 204, Baxter-Amicus, Gambro BCT COBE Spectra and Gambro BCT-Trima. Collected plasma volumes averaged 300-350 ml for the various systems. Plasma samples were analyzed for platelet (PLT) content (Technicon H3, Bayer) and residual WBC (Imagn 2000). Results are given below. Platelet levels were consistently low for MCS+, COBE Spectra and Trima (all <50 x 10(3) microl(-1)), and were highest with AS204. Residual WBC levels were relatively low in all systems except MCS+. Extremely low levels were observed in Trima plasma. All of the Trima and Spectra units contained <1 x 10(6) WBC per product. With Excel, AS-Tech 204 and Amicus, 1 to 2 units were found to have >1 x 10(6) WBC, while almost all units from MCS+ exceeded this limit. Different levels of plasma purity were obtained with different apheresis systems. The Gambro BCT COBE Spectra and Trima systems were found to achieve consistently low levels of both platelets and WBC.

Humans↗
PubMed2001

Molecular characterization of the PK-LR gene in sixteen pyruvate kinase-deficient patients.

We studied the PK-LR gene in 16 unrelated patients with congenital haemolytic anaemia associated with erythrocyte pyruvate kinase deficiency. Fifteen different mutations were detected among the 28 mutated alleles identified: two deletions (del 1010G, del 1042--1044); one four nucleotide duplication (nt 1515--1518, GGTC); one splice site [IVS6(-2)t]; nine missense (991A, 1003A, 1151T, 1160G, 1181T, 1181A, 1456T, 1483A, 1529A); and two nonsense (721T, 1675T) mutations. Eight of them [del 1010G, del 1042--1044, dupl 1515--1518, IVS6(-2)t, 1003A, 1160G, 1181T, 1181A] were novel. The deletion 1042-1044 causes the loss of Lys 348. Deletion 1010G and duplication 1515-1518 determine a frameshift and the creation of a stop codon at nucleotides 1019 and 1554 respectively. Mutation IVS6(-2)t leads to an alteration of the 5' and 3' splice site consensus sequence; the cDNA analysis shows a 67-bp deletion in the first part of exon 11 (del 1437--1503). All the four new missense mutations involve highly conserved amino acids. The most frequent mutation in Italy would appear to be 1456T. Correlation was made between mutations, biochemical characteristics of the enzyme and clinical course of the disease.

Adult↗
PubMed2000

In vitro quantification of anti-red blood cell antibody production in idiopathic autoimmune haemolytic anaemia: effect of mitogen and cytokine stimulation.

The immunopathogenic mechanisms underlying idiopathic autoimmune haemolytic anaemia (AIHA) are still unknown, although regulatory cytokines are thought to play an important role. We investigated cytokine production by mitogen-stimulated whole blood cultures from 21 patients with AIHA and from 22 age- and sex-matched controls. In parallel experiments, we studied the effect of mitogen and cytokine stimulation on anti-red blood cell (RBC) IgG antibody production, assessed as both binding on autologous RBCs and secretion in culture supernatants. To quantify anti-RBC antibody, we set up a sensitive and quantitative solid phase competitive immunoassay. The results showed that in AIHA patients production of interleukin (IL)-4, IL-6 and IL-13 was significantly increased, whereas that of interferon (IFN)-gamma was reduced. Multivariate analysis showed that IFN-gamma was the only independent factor significantly associated with the reduced T-helper-1-like cytokine profile. Patients with active haemolysis showed further reduction of IFN-gamma and IL-2 production and increased secretion of transforming growth factor (TGF)-beta. In AIHA patients, mitogen stimulation, as well as IL-6, significantly increased autologous anti-RBC-binding relative to unstimulated cultures. Mitogen stimulation and addition of IL-4, IL-6, IL-10, IL-13 and TGF-beta significantly increased both autologous anti-RBC binding and antibody secretion in AIHA patients compared with controls. The results suggest that a reduced T-helper-1- and a predominant T-helper-2-like profile and elevated TGF-beta levels might play a role in the immunopathogenesis of AIHA. Furthermore, our competitive anti-RBC antibody was able to detect anti-RBC antibody production in some direct antiglobulin test (DAT)-negative AIHA patients.

Adult↗
PubMed2000

Sustained response to interferon-alpha2a monotherapy of young blood donors with minimal-to-mild chronic hepatitis C. The Donor Surveillance Study Group.

Subjects with minimal-to-mild chronic hepatitis C may suffer long-term consequences of hepatitis C virus (HCV) infection. Nonetheless, they are not candidates for antiviral treatment, mainly because little data are available concerning the efficacy and safety of therapy. Thirty-two HCV RNA positive individuals aged 18-45 years, who had a histological activity index score < or = 8 and alanine aminotransferase (ALT) levels < or = 1.5 times lower than the normal limit for at least 1 year, were prospectively enrolled among a cohort of 35358 candidate blood donors, and treated with 4.5 mega units (MU) of recombinant interferon-alpha2a (IFN-alpha2a) thrice weekly for 6 months, and for an additional 6 months if a virological response was observed. Twelve months after the completion of treatment, 13 of 31 evaluable patients were HCV RNA negative, accounting for a sustained response rate of 42%. Patients without fibrosis had a lower response rate than those with mild fibrosis (two of 14 vs 11 of 17; P=0.012). In responders, median aminotransferase levels were significantly lower after therapy than before (11.04 +/- 3.98 vs 27.3 +/- 12.32 U l-1, respectively; P < 0. 005). When the analysis was limited to the six responders whose pretreatment aminotransferase levels were consistently normal, this difference was still significant (9.33 +/- 4.12 vs 20.58 +/- 6.73 U l-1; P=0.002). In conclusion, a durable suppression of viraemia can be obtained by IFN monotherapy in a relatively high proportion of young subjects with minimal-to-mild chronic hepatitis C, especially when portal fibrosis is found on liver biopsy. The disappearance of viraemia always leads to a reduction in the degree of hepatocellular necrosis.

Adolescent↗