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Biomedical subjects

M Orlandi

Publications and source records attributed to M Orlandi.

At least 19 recordsLinked to original sources
PubMed2006

[Chronic gastrointestinal bleeding].

Chronic gastrointestinal bleeding can occur as recurrent overt blood loss (hematochezia, melena or hematemesis) or as occult gastrointestinal bleeding. Occult bleeding from the gastrointestinal tract is typically identified by either a positive stool test for occult blood or by the presence of iron deficiency anemia. The major cause of iron deficiency anemia is blood loss from the gastrointestinal tract. In women, menstrual blood loss must also be considered. Approximately 5% of all patients with gastrointestinal bleeding do not have lesions identified by upper or lower endoscopy. In most of these patients, the bleeding source responsible for the chronic blood loss is located in the small bowel. The most common cause for gastrointestinal bleeding of small bowel origin is angiodysplasia, tumors of the small intestine (primary benign or malignant tumors or metastatic lesions) and various other causes (such as ulcers caused by nonsteroidal antiinflammatory drugs, aortoenteric fistula, diverticula, endometriosis and hemobilia). After negative upper and lower endoscopy, examination of the small bowel is warranted. Methods to evaluate the small bowel include enteroscopy, capsule endoscopy, small bowel radiographic studies and angiography. The role of each examination depends upon the clinical setting and available expertise. Explorative surgery with intraoperative enteroscopy is generally reserved for patients with ongoing transfusion requirement and in those under the age of 5O years (to rule out a small bowel neoplasm). This article reviews the concepts of evaluation and care of patients with chronic gastrointestinal bleeding.

Chronic Disease↗
PubMed2005

Comparison of incidence of sepsis in cancer patients that underwent systemic or loco-regional chemotherapy.

In this retrospective non controlled trial we evaluated the incidence of sepsis in cancer patients in two different periods (January-June 2003 versus January-June 2004). The main difference in these two periods was that in our oncology department we changed from systemic chemotherapy to loco-regional chemotherapy using less myelosuppressive drugs and developed the domiciliary assistance. The aim of the study was to assess the incidence of sepsis in order to demonstrate a reduction of the infection related to the change of chemotherapy. In addition, this study may be able to describe the epidemiology of sepsis in cancer patients afferent to our oncology department. The incidence of sepsis was reduced in the second period from 24.3% to 6.2%. The pathogens more frequently isolated in this study were coagulase-negative staphylococci (CNS) followed by Escherichia coli and Staphylococcus aureus. Less invasive therapy may reduce infective complication of chemotherapy. The epidemiology of sepsis may be very helpful to design empiric therapeutic protocol for febrile patients that have received chemotherapy.

Adult↗
PubMed2004

Oxidation of milled wood lignin with laccase, tyrosinase and horseradish peroxidase.

In this paper the oxidation of milled wood lignin (MWL), catalysed by three enzymes, i.e. laccase, tyrosinase and horseradish peroxidase (HRP) was studied. The oxidation was followed by measuring the consumption of O(2) during laccase and tyrosinase treatment and of H(2)O(2) during HRP treatment. Both laccase and HRP were found to oxidise lignin effectively, whereas the effect of tyrosinase was negligible. The changes in MWL molecular-weight distributions caused in the reactions were analysed by gel permeation chromatography. Both laccase and HRP treatments were found to polymerise MWL. Peroxidase treatment was found to decrease the amount of phenolic hydroxyls in MWL, whereas no such effect could be detected in the laccase-treated sample. Both laccase and HRP treatments were, however, found to increase the amount of conjugated structures in MWL. The formation of phenoxy radicals during the treatments was studied by electron paramagnetic resonance spectroscopy. Phenoxy radicals were detected in both laccase and HRP-treated samples. The amount of the formed phenoxy radicals was found to be essentially constant during the detected time (i.e. 20-120 min after the addition of enzyme).

Biotechnology↗
PubMed2002

Anaerobic removal of linear alcohol ethoxylates.

The present paper deals with a laboratory-scale study of anaerobic treatment of two commercial mixtures (LS2, LT7) of alcohol ethoxylates with 8-14 carbon atoms and 2 and 7 ethoxy groups. Tests were carried out in batch, with a 2 g l(-1) single dose, and in semibatch, with daily 0.2 g l(-1) doses. The behaviour of the tested mixtures was different: anaerobic sludge adsorption was the main removal process for LS2, while adsorption was less significant and biodegradation was more important for LT7. These differences appeared to be mainly related to the ethoxy portion length determining the extent of biodegradability and adsorption.

Adsorption↗
PubMed2001

Gas-phase reaction of phenol with NO3.

The fast gas-phase reaction of NO3 radicals with phenol was found to yield 2-nitrophenol as the only relevant nitration product. The yield of this product was high and independent of the concentration of NO2 at the concentrations applied. In the presence of ozone, also significant amounts of 4-nitrophenol and p-benzoquinone were formed. The rate constant of the reaction between NO3 radicals and phenol was determined to be 5.8 x 10(-12) cm3 molecule-1 s-1. The selective formation of 2-nitrophenol (2) is suggested to derive from either the concerted keto-enol tautomerism in the reaction of a phenoxy radical with NO2 or the concerted elimination of nitric acid from a cyclohexa-3,5-diene intermediate.

Air Pollutants↗
PubMed2000

Allergenicity of mare's milk in children with cow's milk allergy.

BACKGROUND: Cow's milk allergy is a common disease of infancy and early childhood. If the baby is not breast-fed, a substitute for cow's milk formula is necessary. OBJECTIVE: The aim of this study was to investigate, in vitro and in vivo, the allergenicity of mare's milk in a population of selected children with severe IgE-mediated cow's milk allergy. METHODS: Twenty-five children (17 male and 8 female) aged 19 to 72 months (median age 34 months) with IgE-mediated cow's milk allergy were selected for this study. All the children underwent skin prick tests with cow's milk and mare's milk and double-blind placebo-controlled oral food challenge (DBPCOFC) with fresh cow's milk, fresh mare's milk, and, as placebo, a soy formula (Isomil, Abbott, Campoverde, Italy). We performed immunoblotting of cow's and mare's milk developed with IgE from allergic children. RESULTS: All the children showed strong positive skin test responses to cow's milk (4+); 2 children had positive skin test responses to mare's milk (2+). All children had positive DBPCOFCs to cow's milk; one child had a positive DBPCOFC to mare's milk. No children reacted to the placebo (Isomil). In the cow's milk, some proteins are able to strongly react with human IgE; when the sera are tested with mare's milk, the bands corresponding to the same proteins are recognized by a lower percentage of sera. CONCLUSION: These data suggest that mare's milk can be regarded as a good substitute of cow's milk in most children with severe IgE-mediated cow's milk allergy. It would be prudent, however, to confirm its tolerability by a supervised titrated oral challenge test.

Administration, Oral↗
PubMed1997

Retroconduction selective recognition in wide-dipole floating atrial sensing. The Multicenter Study Group.

Effective discrimination of retrogradely conducted P waves would allow distinguishing sinus tachycardia from supraventricular tachycardias due to AV or nodal reentry, and would prevent pacemaker-mediated tachycardia in AV sequential pacing. This might be especially relevant in VDD implants, where retroconduction could be induced by escape ventricular stimulation. In order to analyze the respective waveform properties, anterograde and retrograde atrial signals were recorded by a wide floating electrode dipole, on the implantation of a permanent single-pass lead for VDD pacing. Generally, bipolar recording did not allow reliable discrimination, while the signal nature could be readily diagnosed from the main features of the unipolar atrial electrograms. The unipolar waveform recorded under sinus rhythm in high right atrium, close to the superior vena cava opening (proximal EGM), started with a negative deflection in 88% of the patients. In 7% of the patients, the first deflection of the signal was positive in some cardiac cycles only, and, on the average, the amplitude of the positive phase was not higher than 5% of the signal peak-to-peak amplitude. Conversely, under retroconduction, the starting deflection attained higher positive values in 98% of the patients, being stably over 15% of the peak-to-peak amplitude in 86% of the Furthermore, in 69% of the cases, the lag time between the onset of the negative deflection of proximal and distal (mid-low atrium) unipolar EGM changed unambiguously when retroconduction occurred, exceeding the range of variation observed in each patient during sinus activity. The combined evaluation of unipolar EGM shape and lag time allowed specific retroconduction recognition in 95% of the patients. We suggest that this approach may yield useful information for the discrimination of retrograde atrial signals, provided that the recording dipole is sufficiently long and the proximal electrode is properly positioned in the high right atrium.

Cardiac Pacing, Artificial↗
PubMed1997

Comparison of recent trends in adolescent and adult cigarette smoking behaviour and brand preferences.

OBJECTIVE: To compare trends in smoking behaviour and use of cigarette brands by adults and adolescents. DESIGN: Data analysed in this paper come from tobacco use surveys of adults and teenagers conducted in 18 communities in the United States, as part of the National Cancer Institute's Community Intervention Trial for Smoking Cessation. Data on adult smoking behaviour were obtained from two cross-sectional telephone surveys, one conducted from January to May 1988 (n = 99348), and the second conducted between August 1993 and January 1994 (n = 79890). Data on adolescent smoking behaviour were obtained from two school-based surveys of ninth-grade students (aged 13-16 years), one conducted in autumn 1990 (n = 7097), and the second conducted in autumn 1992 (n = 7277). OUTCOME MEASURES: Adult cigarette smoking prevalence was estimated as the percentage of adults (18+ years) who were identified either by interview or by proxy as a current smoker. Among adolescents, current smokers were defined as those who reported having smoked on one or more of the 30 days preceding the interview. Cigarette brand use by adults was measured by asking current smokers to report the six digit UPC code on the side of the pack of their current cigarettes. A master list of UPC code numbers was developed so that reported codes could be associated with specific brand names. Among adolescents, cigarette brand use was measured by asking current smokers who reported that they usually buy their own cigarettes: "What brand do you usually buy?" RESULTS: In ninth-grade students, smoking prevalence rates increased between 1990 and 1992 in 13 of the 18 communities. Among adults, smoking rates declined between 1988 and 1993 in 17 out of 18 communities. Within the same communities, cigarette brand use was found to be much more tightly concentrated in adolescent smokers compared with adults, with teenage smokers more likely to report using the most heavily advertised cigarette brands--Marlboro, Newport, and Camel. CONCLUSIONS: Smoking prevalence rates have increased among teenagers, but have dropped among adults in the same communities. Among adolescents who smoke, and buy their own cigarettes, the three most heavily advertised brands--Marlboro, Camel, and Newport--have a substantially higher market concentration than among adult smokers.

Adolescent↗
PubMed1996

Anticonvulsant effect of felbamate in the pentylenetetrazole kindling model of epilepsy in the rat.

The present study was designed to examine the ability of felbamate, a novel antiepileptic agent, to antagonize the increase in seizure severity (i.e., chemical kindling) produced by chronic treatment with initially subconvulsant doses of pentylenetetrazol (PTZ). Rats were treated with PTZ (30 mg/kg, i.p., three times a week) for 8 consecutive weeks. Two other groups of rats received felbamate (300 or 400 mg/kg, i.p.), 90 min before each dose of PTZ. Pretreatment with felbamate at either dose prevented the progression of rank of seizures during chronic treatment with PTZ. Thus, the mean seizure score by the end of the chronic treatment (0-5 scale) was 0 in vehicle treated controls, 3.3 in rats treated with PTZ alone, 1.5 in rats treated with PTZ plus felbamate (300 mg/kg, i.p.) and 0.9 in the group treated with PTZ plus felbamate (400 mg/kg, i.p.). Felbamate also antagonized the long-term increase in the sensitivity to the convulsant effects of GABA function inhibitors observed in PTZ-kindled rats. Thus, the administration of a challenge dose of isoniazid (120 mg/kg, s.c.), picrotoxin (1.5 mg/kg, i.p.) or PTZ itself (15 mg/kg, i.p.), 15 to 45 days after the end of the chronic treatment regimen, induced convulsions in > 80% of PTZ-kindled rats and in < 20% of rats treated with PTZ + felbamate (400 mg/kg). The results are discussed in terms of the multiple mechanisms that can contribute to the anticonvulsant action of felbamate in the PTZ kindling model of epilepsy.

Animals↗
PubMed1996

Tilt test results in young and elderly patients with syncope of unknown origin.

The effects of aging on the results of prolonged drug-free tilt testing were studied in 175 consecutive patients with unexplained syncope divided into 3 groups: 59 patients < 40 years old; 57 patients between 40 and 60 years; and 59 patients > 60 years old. Tilt-induced vaso-vagal syncope occurred respectively in 17 (29%), 20 (35%), and 18 patients (31%) in the 3 age groups. Vasodepressor, mixed, and cardioinhibitory vaso-vagal syncope occurred similarly in the 3 groups; organic heart disease and systemic hypertension were more frequent in elderly patients without affecting the incidence of tilt-induced syncope. Blood pressure and heart rate variations during syncope were similar in the 3 age groups; in the first 20 minutes of tilt testing, before the appearance of the vaso-vagal reflex, elderly patients showed greater reduction in blood pressure and smaller increase in heart rate than younger patients. Our data indicate that increasing age determines a different blood pressure and heart rate behavior during tilt testing, but apparently does not influence the incidence of vaso-vagal syncope in patients with syncope of undetermined etiology. As the proportion of patients with a positive isoproterenol tilt test was reported to decline with age, our results suggest that the reduced incidence of syncope during isoproterenol tilt testing could be the expression of impaired autonomic response among elderly syncope patients.

Adult↗
PubMed1996

Kinetics of tert-[35S]butylbicyclophosphorothionate binding in the cerebral cortex of newborn and adult rats: effects of GABA and receptor desensitization.

The effects of GABA on the kinetics of tert-[35S]butylbicyclophosphorothionate ([35S]TBPS) binding to the convulsant site of GABAA receptors were studied in membrane suspensions from the cerebral cortex of newborn (1-day-old) and adult (90-day-old) rats. TBPS dissociation was biphasic in neonates and adults, indicating that more than one interconvertible state of [35S]TBPS binding sites may be present in the cerebral cortex. In the absence of GABA, the fast (t1/2, 11 min) and slow (t1/2, 77 min) components of TBPS dissociation in newborn rats were approximately fourfold slower than in adults. The acceleration of the dissociation rates caused by 2 microM GABA, however, was more robust in neonates than in adults (six- to ninefold vs. twofold increase, respectively). Moreover, the dissociation rates of TBPS in membranes preincubated with 2 microM GABA (dissociation started by adding 40 microM picrotoxin) were two- to fourfold slower than in membranes preincubated without GABA (dissociation started by adding 40 microM picrotoxin plus 2 microM GABA). Taken together, these results suggest that (1) the closed state of GABAA receptors is associated with a more effective steric barrier for the binding of TBPS in neonates compared with adults, (2) GABA produces a larger acceleration of the binding kinetics of TBPS in neonates than in adults, and (3) long incubations with GABA may cause receptor desensitization, which in turn slows down the dissociation rates of TBPS.

Age Factors↗
PubMed1996

Daily fluctuations of haematology and blood biochemistry in horses fed varying levels of protein.

Changes in the plasma biochemistry of 12 stallions were studied over seven 24 h periods. Twelve healthy male horses of 4 different breeds (Thoroughbred [TB], Anglo-Arabo-Sardo [AAS], Avelignese [Av] and Maremmano [M]) were divided into 3 experimental groups and fed with an isoenergetic maintenance ration with different protein levels. The same amount of food was given daily at 0730 and 1930 h. After 20 days of pretrial, a series of 6 blood samples were collected daily from the jugular vein every 4 h for 7 days. The samples were analysed for packed cell volume (PCV), haemoglobin, plasma glucose, free fatty acids, cholesterol, total plasma protein, urea, creatinine, calcium, phosphorus and enzymatic activities: aspartate aminotransferase (AST), alanine aminotrasferase (ALT), creatine kinase (CK) and lactate dehydrogenase (LDH). The data were analysed following the armonic analysis (Fourier) in order to define the pattern of biorhythm. Many parameters showed a biorhythmical pattern. Protein levels of the diet failed to influence haematology, blood biochemistry and biorhythm. Thoroughbreds showed the highest values of PCV, haemoglobin and creatinine and the lowest total protein, phosphorus and enzymatic activities.

Analysis of Variance↗
PubMed1995

Post-transcriptional regulation of thromboxane A2 synthase in U937 cells.

Translation of mRNAs is a process usually tightly coupled to transcription of genes. However, there are examples of mRNA species which accumulate without being translated. Some mRNAs present in oocytes and ferritin mRNA are the most studied models. Studying the biogenesis of thromboxane A2 (TXA2) in the promonocytic line U937, we have noted that in proliferating cells high levels of TXA2 synthase mRNA are detectable by Northern blot, whereas no TXA2 could be recovered in the medium. This has been explained on the basis of Western blot experiments: TXA2 synthase was not detectable in proliferating cells, while a band of about 55 kd appears after treatment with the differentiating agent TPA. Immunofluorescence detection by confocal microscopy was in agreement with Immunoblot results. Thus, in U937 cells, TPA behaves as a regulator of translation of TXA2 synthase mRNA. We have further observed that the induced enzyme in U937 cells has many characteristics in common with the human monocytic enzyme: a long half life (> 24 hrs), a marked stability during catalysis and similar Km and Vmax values. Thus, U937 cells are a good model to study the mechanism by which a mRNA is efficiently translated only after differentiation has been triggered.

Animals↗
PubMed1995

Prostacyclin (PGI2) synthase is a constitutively expressed enzyme in human endothelial cells.

Biogenesis of prostanoids is under the control of some polypeptide growth factors. Cytosolic phospholipase A2, a form specific for arachidonic acid containing phospholipids, is activated by a translocation mechanism regulated by growth factors, while prostaglandin H synthase isoforms are induced de novo in several cell types. No information is available as far as PGI2 synthase is concerned. Human umbilical vein endothelial cells were cultured under conditions favoring proliferation or differentiation or capillary-like network formation in the presence of collagen gels. Basic fibroblast growth factor (bFGF 0.5-4 ng/ml) was used as a mitogen, interleukin-1 alpha (IL-1 alpha 10-60 UI/ml) as a differentiating agent, and prostacyclin (PGI2) biosynthesis was evaluated. Under the first condition, basal PGI2 production was unaffected while, in the presence of IL-1 alpha, a marked stimulation of PGI2 synthesis was observed. It is known that IL-1 alpha is a potent inducer of PGH synthase, while it is not known whether PGI2 synthase is also induced. Two lines of evidence indicate that PGI2 synthase is a constitutively expressed not inducible enzyme: (a) proliferating nonproducing cells when added with PGH2 produce an amount of PGI2 not different from the amount produced by cells stimulated with IL-1 alpha; (b) under this condition PGI2 synthase was immunodetectable either by immunofluorescence detected by confocal microscopy or by ELISA and, on microsomes isolated from endothelial cells, by Western blotting. It is concluded that the limiting step in the conversion arachidonate-PGI2 is represented solely by the level of PGH synthase. These results strongly suggest, but do not prove, the constitutive nature of the enzyme. The final demonstration requires the availability of a probe to detect mRNA level, a trial we are carrying out at the moment.

Cell Division↗
PubMed1995

Smokers' baseline characteristics in the COMMIT trial.

BACKGROUND: Baseline telephone survey data from 10 COMMIT sites were submitted to statistical analyses to compare the smoking characteristics of non-Hispanic white (white), non-Hispanic black (black), Mexican-origin (Mexican), and Puerto Rican-origin (Puerto Rican) smokers. RESULTS: White men and women were more likely to be classified as "heavy smokers" than members of other racial/ethnic groups, although black and Puerto Rican smokers were more likely than whites to increase their smoking rates on weekends. Whites were less likely to report stopping smoking in the past. White and Mexican smokers were most likely to smoke light or ultralight brands and least likely to smoke menthol cigarettes. Blacks were most likely to report smoking their first cigarette of the day within 10 min of waking. CONCLUSION: The differences and similarities among different groups of smokers may have important implications for understanding patterns of tobacco-related disease in smokers from different racial/ethnic and sex groups.

Adult↗
PubMed1995

Comparison of hemodialysis versus hemoperfusion in the clearance of high-dose methotrexate in pigs.

To evaluate the different capabilities of hemo-perfusion (HP) and hemodialysis (HD) treatment in resolving the side effects during high-dose methotrexate (MTX) therapy, an experimental comparative study was done. Under general anesthesia, 12 female Large-White pigs, 35 +/- 5 kg body weight, underwent a bilateral renal vessel ligature to create an acute renal failure and avoid the physiologic elimination of MTX. An MTX i.v. infusion was performed using a dose of 12.5 g/m2 and for a specific time according to its pharmacokinetics. The animals were divided into 2 groups of 6 animals each and connected to the extracorporeal circuit; the first group was submitted to a 1-h HP with an anion exchange resin (Dow 1X-2, Dow Chemical) and the second group to 1-h HD with capillary polysulfone fibers (F6, Fresenius). Blood samples were taken at established intervals for hematological and biochemical evaluations. The results demonstrate a higher capability of HP treatment (P < 0.001) related to HD in MTX removal.

Animals↗