PubMed Health⌕ Search

Biomedical subjects

C Merli

Publications and source records attributed to C Merli.

17 recordsLinked to original sources
PubMed2004

The SF-36 instrument for the follow-up of health-related quality-of-life assessment of patients undergoing home parenteral nutrition for benign disease.

INTRODUCTION: The non-disease-specific SF-36 instrument was applied to detect changes in quality of life among patients at a single center who were receiving home parenteral nutrition (HPN) for intestinal failure. METHODS: All HPN patients completed the questionnaire during routine visits. The SF-36 examines eight domains (scores: 0% to 100%): physical functioning (PF), role-functioning physical (RP), body pain (BP), general health (GH), vitality (VT), social functioning (SF), as well as role-functioning emotional (RE) and mental health (MH). Patient responses were standardized for the sex- and age-matched group scores of the healthy population by calculating the Z-score: (healthy population mean score - patient raw score)/healthy population standard deviation (reduced value: Z-score < -1). A difference in a domain score was considered significant in the individual patient if it was greater than the 90% confidence interval for healthy subjects and if it produced a change in Z-score category. General, sociodemographic, underlying disease and HPN-related factors were collected. RESULTS: For 31 enrolled adult patients, the baseline mean Z-score was reduced in five domains: PF, RP, BP, GH and SF. Twenty patients underwent a second SF-36 assessment 10 +/- 2 months later: the HRQOL worsened in eight and improved in 10 (no. worsened domains > no. improved or vice versa). The worsened subgroup showed a decrease in body mass index (P =.104), an increase in the number of HPN infusions per week (P =.065), and a greater incidence of intestinal motility disorders (P =.161), of liquid oral diet (P =.027), and of nycturia (P =.028). CONCLUSIONS: The SF-36 instrument reflecting the generic HRQOL assessment may be a suitable tool for patients on HPN.

Adolescent↗
PubMed2004

Italian guidelines for intestinal transplantation: potential candidates among the adult patients managed by a medical referral center for chronic intestinal failure.

In 2002, the Italian guidelines for eligibility of patients for intestinal transplantation (ITx) were defined as: life-threatening complications of home parenteral nutrition (HPN), lack of venous access for HPN, locally invasive tumors of the abdomen, Chronic intestinal failure (CIF) with a high risk of mortality, primary disease-related poor quality of life (QoL) despite optimal HPN. Our aim was to identify potential candidates for ITx according to these national guidelines among patients managed by a medical referral center for CIF. Records of patients who received HPN were reviewed. CIF was considered reversible or irreversible (energy by HPN <50% or >50% basal energy expenditure). Patients with irreversible CIF were considered eligible for ITx in the absence of a contraindication, as are used for solid organs Tx. From 1986 to 2003 among 64 patients who met the entry criteria 23 showed reversible and 41 irreversible, CIF. Twenty-one patients with irreversible CIF had an indication for ITx, but eight had also contraindications; thus 13 were eligible, including intestinal pseudo-obstruction (n = 6), mesenteric ischemia (n = 3), Crohn's (n = 2), radiation enteritis (n = 1), and desmoid (n = 1). Indications for ITx included HPN liver failure (n = 2), lack of venous access (n = 2), CIF with high risk of mortality (n = 3), very poor QoL (n = 6 including 5 with pseudo-obstruction). According to the Italian guidelines for ITx, 31% of patients with irreversible CIF managed by a medical referral center were eligible for ITx. Primary disease-related poor QoL was the indication in half of them. Studies on the QoL after ITx are required to allow patients to make an educated decision.

Adult↗
PubMed2004

Effect of ethanol on the oxidation of atrazine in the remediation of contaminated soil.

The oxidation of an atrazine solution obtained from a flushing treatment of a contaminated soil was investigated. Experimental tests were performed on an artificially contaminated standard soil. Atrazine was removed from the soil by flushing with an aqueous solution at 5% volume of ethanol. Oxidative Fenton-type treatment on the extracted solution was then performed in order to transform atrazine into its by-products. The influence of different concentration of ethanol on atrazine oxidation was studied. Results show that the oxidative treatment is strongly affected by the ethanol residual amount. The degradation mechanism of atrazine during oxidation with Fenton's reagent in the presence of ethanol was also investigated.

Atrazine↗
PubMed2003

Recovery of EDTA and metal precipitation from soil flushing solutions.

This work studies the effectiveness of a process proposed for the recovery of ethylenediaminetetraacetic acid (EDTA) and metal precipitation from soil flushing solutions. Two series of experimental tests were carried out on two samples of a soil artificially contaminated with copper or lead. The metals were extracted from the soil by flushing with a 0.05 M aqueous solution of EDTA sodium salt (E-Na(2)). Cu or Pb extraction efficiencies of about 95 and 98% were observed, respectively. The two extracted solutions were then treated to obtain EDTA recovery and metal precipitation from the aqueous solution. EDTA recovery was achieved in two steps. An initial evaporation treatment lead to reduce the solution volume by about 75%. This was followed by the acidification of the residue solution, which precipitated more than 93% of the used EDTA. The precipitated EDTA was removed by filtration, and was suitable for reuse after adding an alkaline agent. Metal precipitation from the filtered solution was performed using two different methods: an almost total (99.5%) Pb precipitation in alkaline conditions was achieved after complex destabilization through the sequential addition of ferric ions and sodium phosphate, while 93.6% copper precipitation was achieved with ferrous sulfate as a destabilization agent.

Chelating Agents↗
PubMed2003

A steady-state model for the evaluation of disk rotational speed influence on RBC kinetic: model presentation.

The physical and biological mechanisms of attached-biomass growth were analyzed and a steady-state model was proposed to determine the soluble carbonaceous removal in an RBC unit for different organic loading rates in the reactor. The objective of the model was the prediction of the organic loading rate corresponding to the maximum removal capacity in the system. A system of equations was solved where the influent soluble carbonaceous substrate concentration was the main variable. Monod's rate law was used for the growth of microorganism: the soluble carbonaceous substrate was the limiting substrate. Endogenous decay was neglected. The influence of disk rotational speed on the RBC removal capacity was investigated, the disk rotational speed being a parameter acting on oxygen transfer in the biofilm. The criteria for the evaluation of the kinetic parameter in the model were proposed.

Bacteria↗
PubMed2003

Safety and efficacy of home parenteral nutrition for chronic intestinal failure: a 16-year experience at a single centre.

BACKGROUND: Comparisons between safety and efficacy of home parenteral nutrition and of intestinal transplantation for treatment of chronic intestinal failure derived from observational studies. AIMS: To present the 16-year experience of home parenteral nutrition by the Chronic Intestinal Failure Centre of Bologna University. PATIENTS: A total of 40 adult patients were enrolled between 1986 and 2001. METHODS: Safety indices: survival and cause of death, catheter-related bloodstream infection, deep vein thrombosis, liver disease. Efficacy indices: nutritional and rehabilitation status, quality of life (SF36 instrument), re-hospitalisation rate. STATISTICS: Kaplan-Maier analysis and Cox model for survival probability and risk factors; logistic regression for catheter-related bloodstream infection risk factors. RESULTS: Survival rates at 1, 3 and 5 years were 97, 82 and 67% respectively. Survival was higher in patients < or = 40 years. One death was home parenteral nutrition-related. Incidence of catheter-related bloodstream infection: 0.30/year home parenteral nutrition, was lower in patients treated by a specialized nursing protocol. Incidence of deep vein thrombosis was 0.05/year home parenteral nutrition. Hepatosteatosis occurred in 55%. Body weight remained stable or increased in 80%. Rehabilitation was total or partial in 74%. Re-hospitalisation rate was 0.70/year home parenteral nutrition. Quality of life scored significantly lower than in healthy populations in six out of eight domains. CONCLUSIONS: Home parenteral nutrition is a safe and efficacious therapy for chronic intestinal failure. Survival compares favourably with survival after intestinal transplantation.

Adolescent↗
PubMed2000

Oral rehydration solution containing rice maltodextrins in patients with total colectomy and high intestinal output.

Oral rehydration solutions containing rice maltodextrins (R-ORS) have been reported to be more effective than glucose-based ORS in reducing intestinal losses in infectious diarrhea. To evaluate the effect of R-ORS in patients with total colectomy and high intestinal output, a perspective open noncontrolled study was performed on 13 adult patients who consumed 1 l/day of R-ORS for 7 days. Body weight, daily ileal and urinary output, serum electrolytes, aldosterone and renin activity were measured the day before (day 0) and on the last day of the study (day 7). Net changes (mean +/- SE) from day 0-7 showed an increase of urine Na (40 +/- 16 mmol/day, p < 0.04) and K (24 +/- 8 mmol/day, p < 0.02). Body weight increased in seven patients. Serum renin activity decreased (-0.60 +/- 0.26 ng/ml/min) in these patients but not in the six patients in whom body weight remained unchanged (0.19 +/- 0.07 ng/ml/min; p < 0.03). Ileal and urinary volume remained stable. In patients with high ileal output, R-ORS supplementation improved Na and K balance. The association of increased body weight with decreased serum renin concentrations suggests that a positive water balance also occurred.

Adult↗
PubMed1998

In vitro reconstitution of Artemia satellite chromatin.

We report the characterization of an in vitro chromatin assembly system derived from Artemia embryos and its application to the study of AluI-113 satellite DNA organization in nucleosomes. The system efficiently reconstitutes chromatin templates by associating DNA, core histones, and H1. The polynucleosomal complexes show physiological spacing of repeat length 190 +/- 5 base pairs, and the internucleosomal distances are modulated by energy-using activities that contribute to the dynamics of chromatin conformation. The assembly extract was used to reconstitute tandemly repeated AluI-113 sequences. The establishment of preferred histone octamer/satellite DNA interactions was observed. In vitro, AluI-113 elements dictated the same nucleosome translational localizations as found in vivo. Specific rotational constraints seem to be the central structural requirement for nucleosome association. Satellite dinucleosomes showed decreased translational mobility compared with mononucleosomes. This could be the consequence of interactions between rotationally positioned nucleosomes separated by linker DNA of uniform length. AluI-113 DNA led to weak cooperativity of nucleosome association in the proximal flanking regions, which decreased with distance. Moreover, the structural properties of satellite chromatin can spread, thus leading to a specific organization of adjacent nucleosomes.

Adenosine Triphosphate↗
PubMed1996

Promoter specificity mediates the independent regulation of neighboring genes.

Although enhancers can exert their influence over great distances, their effect is generally limited to a single gene. To discern the mechanism by which this constraint can he mediated, we have studied three neighboring Drosophila genes: decapentaplegic (dpp), SLY1 homologous (Slh) and out at first (oaf). Several dpp enhancers are positioned close to Slh and oaf, and yet these genes are unaffected by the dpp elements. However, when a transposon is located within the oaf gene, the dpp enhancers activate the more distant transposon promoters while still ignoring the closer Slh and oaf start sites. To test whether this promoter specificity accounts for the regulatory autonomy normally found for the three genes, we used in vivo gene targeting to replace the oaf promoter with a dpp-compatible one in an otherwise normal chromosome. Strikingly, this chimeric gene is now activated by the dpp enhancers. Thus, the properties of the promoters themselves are sufficient to mediate the autonomous regulation of genes in this region.

Animals↗
PubMed1992

Effects of barium and 5-(N-ethyl-N-isopropyl)-amiloride on proximal tubule ammonia transport.

Ionic NH+4 transport is an important mode of ammonia transport in the proximal convoluted tubule (PCT). NH+4 transport via the Na-H exchanger has been previously demonstrated. Potassium channels are present in the proximal tubule, but their role in ammonia transport has not been evaluated. We studied rat PCTs perfused in situ at 30 nl/min with solutions containing 5 mM HCO3; ammonia was measured with a fluorometric method. When perfused with the potent amiloride analogue 5-(N-ethyl-N-isopropyl)-amiloride (EIPA, 500 microM) or with BaCl2 (10 mM), ammonia entry (14.3 +/- 1.7 and 11.8 +/- 1.5 pmol.min-1.mm-1, respectively) was unaffected compared with control (12.8 +/- 1.0 pmol.min-1.mm-1). However, the combination of EIPA and barium inhibited entry (7.4 +/- 1.0 pmol.min-1.mm-1, P less than 0.02 vs. other groups). Also, when perfused with 10 mM ammonia, neither EIPA nor BaCl alone blocked ammonia loss (70.5 +/- 9.1 and 60.5 +/- 5.9 pmol.min-1.mm-1, respectively) compared with control (53.4 +/- 6.0 pmol.min-1.mm-1). However, the combination inhibited ammonia loss (29.2 +/- 6.3 pmol.min-1.mm-1, P less than 0.025 vs. other groups). Thus blocking both the Na-H exchanger and potassium channels decreases PCT ammonia transport. As the combination was required, this implies that multiple pathways exist for NH+4 transport in the PCT. This is the first demonstration that a mode of NH+4 transport other than via the Na-H exchanger is important in this segment, and the data are most consistent with transport of ammonia via potassium channels.

Amiloride↗
PubMed1990

Contribution of luminal ammoniagenesis to proximal tubule ammonia appearance in the rat.

The contribution of luminal ammoniagenesis in the late proximal convolute tubule (PCT) via phosphate-independent glutaminase [gamma-glutamyltransferase (gamma-GT)] remains controversial. If this pathway is important, it must rely on glutamine secretion, because filtered glutamine is reabsorbed in the early PCT. The contribution of gamma-GT to luminal ammoniagenesis was tested by use of in vivo microperfusion in conjunction with a new microfluorometric assay for glutamate. We first confirmed that aspartate completely blocked glutamate uptake in the PCT. Furthermore, the gamma-GT inhibitor acivicin completely eliminated glutamate entry, showing that passive glutamate entry was negligible. Thus the accumulation of glutamate can be used as an estimate of luminal glutamine deamidation. L-Phenylalanine was used to inhibit glutamine loss, and hippurate was used to stimulate gamma-GT activity; therefore luminal glutamine conversion to glutamate was promoted. Perfusing the tubule at 30 nl/min with a solution containing 10 mM each of hippurate, phenylalanine, and aspartate resulted in a glutamate delivery of 1.08 +/- 0.12 pmol.min-1.mm-1. Ammonia appearance was 10-fold higher, averaging 11.5 +/- 1.3 pmol.min-1.mm-1 under these same conditions. Thus the luminal conversion of glutamine to glutamate via gamma-GT is a small component of total ammoniagenesis in this segment.

Absorption↗
PubMed1989

Contribution of superficial nephron segments to sodium excretion in experimental glomerulonephritis.

The present study examined the contribution of individual superficial nephron segments to sodium excretion in antiglomerular basement membrane nephritis in the rat by sampling the same nephron successively from the end and beginning of the distal tubule and end of the proximal tubule. Whole kidney GFR in glomerulonephritic rats was reduced by approximately 40% from controls; absolute sodium excretion was about 25% of normal. Metabolic balance studies in the awake state had suggested that the animals were in sodium balance. Plasma renin levels before and during micropuncture were similar to controls. These findings suggest that the defect in sodium handling is intrinsic to the kidney. Glomerulotubular balance was maintained along the proximal tubule. Sodium reabsorption in the loop of Henle was reduced in absolute terms but was proportional to the load delivered. Due to the decreased absolute sodium reabsorption in the preceding segments, sodium delivery to the beginning of the distal tubule was comparable in the two groups of animals. Along the distal tubule sodium reabsorption was comparable to control animals. Therefore, the avid urinary sodium retention seen during micropuncture was due to increased sodium reabsorption by segments past the superficial proximal tubule and/or by deep nephrons.

Animals↗
PubMed1989

Determinants of ammonia entry along the rat proximal tubule during chronic metabolic acidosis.

The technique of in vivo microperfusion was used to examine the determinants of ammonia entry along the rat proximal tubule under conditions of chronic metabolic acidosis (CMA). When perfused with a 5 mM bicarbonate-containing perfusate, collected fluid ammonia concentrations remained constant with increasing flow rate and thus ammonia entry was highly flow-rate dependent. Ammonia entry was also flow-rate dependent using a 25 mM bicarbonate perfusate but entry reached a plateau as perfusion rate increased. Also, ammonia entry tended to be lower at all perfusion rates with the 25 mM perfusate compared with the 5 mM bicarbonate perfusate, but this was most evident at the highest perfusion rate (45 nl/min). The decline in ammonia entry was associated with increasing collected fluid bicarbonate concentrations, suggesting that there was inhibition of diffusion trapping of ammonia. The effects of Na+-H+ exchange inhibition on ammonia entry were examined using the amiloride analogue, 5-(N-ethyl-N-isopropyl)amiloride. With a 25 mM bicarbonate-containing perfusate, the amiloride analogue caused a significant decrease in bicarbonate reabsorption but a nonsignificant decrease in ammonia entry associated with a significant rise in collected fluid bicarbonate concentration. When the potential effects of decreased diffusion trapping of ammonia were eliminated with 12 and 5 mM bicarbonate-containing perfusates, the analogue had no effect on ammonia entry despite significant inhibition of bicarbonate reabsorption. Thus ammonia entry in CMA is moderately affected by tubule fluid pH but is highly flow-rate dependent. There were no effects of inhibition of Na+-H+ exchange above those expected from inhibition of diffusion trapping of ammonia.

Acidosis↗
PubMedDate not supplied

Innovative methods for removing phosphorus from wastewaters.

Wastewater containing a mixture of hypophosphites and phosphites was treated in order to assess the possibility of attaining high levels of phosphorus oxidation to phosphate. An initial series of tests based on chemical oxidation by means of Fenton's reagent demonstrated the feasibility of this process for solutions containing 250-750 mg/l of phosphorus. Removal yields of up to 98% were attained at pH 3.5 by using variable ratios of [H2O2]/[Fe2+]. The second series involved the electrolytic generation of Fenton's reagent at pH 2-2.5 through cathodic oxygen reduction. This demonstrated the possibility of obtaining quantitative yields for solutions containing 80-160 mg/l P with a constant [H2O2]/[Fe2+] ratio of 3.94. Economic comparison of the two processes showed that the operative cost of the electrochemical treatment is comparable to that of the chemical process.

Electrochemistry↗