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Biomedical subjects

A Canepa

Publications and source records attributed to A Canepa.

At least 55 records · Page 3Linked to original sources
PubMed2005

First measurements of inclusive W and Z cross sections from run II of the fermilab tevatron collider.

We report the first measurements of inclusive W and Z cross sections times leptonic branching ratios for pp collisions at square root[s]=1.96 TeV, based on their decays to electrons and muons. The data correspond to an integrated luminosity of 72 pb(-1) recorded with the CDF detector at the Fermilab Tevatron. We test e-mu universality in W decays, and we measure the ratio of leptonic W and Z rates from which the leptonic branching fraction B(W-->lnu) can be extracted as well as an indirect value for the total width of the W and the Cabibbo-Kobayashi-Maskawa matrix element, |V(cs)|.

Journal Article↗
PubMed2005

Measurement of Wgamma and Zgamma production in pp collisions at square root s=1.96 TeV.

The standard model predictions for Wgamma and Zgamma production are tested using an integrated luminosity of 200 pb(-1) of pp collision data collected at the Collider Detector at Fermilab. The cross sections are measured by selecting leptonic decays of the W and Z bosons, and photons with transverse energy ET>7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the Wgamma and Zgamma data are compared to SM predictions.

Journal Article↗
PubMed2004

Search for doubly charged Higgs bosons decaying to dileptons in pp collisions at square root of s=1.96 TeV.

We present the results of a search for doubly charged Higgs bosons (H+/-+/-) decaying to dileptons (ll(')) using approximately 240 pb(-1) of pp collision data collected by the CDF II experiment at the Fermilab Tevatron. In our search region, given by same-sign ll(') mass m(ll('))>80 GeV/c(2) (100 GeV/c(2) for ee channel), we observe no evidence for H+/-+/- production. We set limits on sigma(pp -->H++H---->l(+)l('+)l(-)l('-)) as a function of the mass of the H+/-+/- and the chirality of its couplings. Assuming exclusive same-sign dilepton decays, we derive lower mass limits on H(+/-+/-)(L) of 133, 136, and 115 GeV/c(2) in the ee, mumu, and emu channels, respectively, and a lower mass limit of 113 GeV/c(2) on H(+/-+/-)(R) in the mumu channel, all at the 95% confidence level.

Journal Article↗
PubMed2004

Measurement of the tt production cross section in pp collisions at sqrt[s]=1.96 TeV using dilepton events.

We report a measurement of the tt production cross section using dilepton events with jets and missing transverse energy in pp collisions at a center-of-mass energy of 1.96 TeV. Using a 197+/-12 pb(-1) data sample recorded by the upgraded Collider Detector at Fermilab, we use two complementary techniques to select candidate events. We compare the number of observed events and selected kinematical distributions with the predictions of the standard model and find good agreement. The combined result of the two techniques yields a tt production cross section of 7.0(+2.4)(-2.1)(stat)+1.6-1.1(syst)+/-0.4(lum) pb.

Journal Article↗
PubMed2004

Observation of the narrow state X(3872)-->J/psipi+pi- in pp collisions at sqaure root of s=1.96 TeV.

We report the observation of a narrow state decaying into J/psipi+pi- and produced in 220 pb(-1) of p p-bar collisions at =1.96 Tesqaure root of sV in the CDF II experiment. We observe 730+/-90 decays. The mass is measured to be 3871.3+/-0.7(stat)+/-0.4(syst) MeV/c2, with an observed width consistent with the detector resolution. This is in agreement with the recent observation by the Belle Collaboration of the X(3872) meson.

Journal Article↗
PubMed2004

Search for B0s-->micro+micro- and B0d-->micro+micro- decays in pp collisions at square root s = 1.96 TeV.

We report on a search for B(0)(s)-->micro(+)micro(-) and B(0)(d)-->micro(+)micro(-) decays in pp collisions at square root of s=1.96 TeV using 171 pb(-1) of data collected by the CDF II experiment at the Fermilab Tevatron Collider. The decay rates of these rare processes are sensitive to contributions from physics beyond the standard model. One event survives all our selection requirements, consistent with the background expectation. We derive branching ratio limits of B(B(0)(s)-->micro(+)micro(-))<5.8x10(-7) and B(B(0)(d)-->micro(+)micro(-))<1.5x10(-7) at 90% confidence level.

Journal Article↗
PubMed2003

Measurement of prompt charm meson production cross sections in pp collisions at square root s = 1.96 TeV.

We report on measurements of differential cross sections dsigma/dp(T) for prompt charm meson production in ppmacr; collisions at sqrt[s]=1.96 TeV using 5.8+/-0.3 pb(-1) of data from the CDF II detector at the Fermilab Tevatron. The data are collected with a new trigger that is sensitive to the long lifetime of hadrons containing heavy flavor. The charm meson cross sections are measured in the central rapidity region |y|</=1 in four fully reconstructed decay modes: D0-->K-pi(+), D(*+)-->D0pi(+), D+-->K-pi(+)pi(+), D(+)(s)-->phipi(+), and their charge conjugates. The measured cross sections are compared to theoretical calculations.

Journal Article↗
PubMed2001

Acute effects of simultaneous intraperitoneal infusion of glucose and amino acids.

BACKGROUND: The feasibility of simultaneously infusing glucose and amino acid (AA)-based peritoneal dialysis solutions was tested to determine whether peritoneal dialysis patients could achieve an adequate nonprotein calorie/nitrogen ratio while preventing a marked increase in blood urea nitrogen (BUN), which is usually seen if the AAs are administered without glucose. METHODS: An automatic peritoneal dialysis cycler was used to infuse glucose and AA solutions (3:1) simultaneously during the night. Eight infusions of 1000 mL m2 of body surface area (BSA), with a 60 minute dwell time, were performed in 10 children on peritoneal dialysis. The dialytic effluent was analyzed at every exchange and totaled at eight hours to evaluate volume, glucose, and AA concentration. Blood samples for plasma, glucose, insulin, and free AA determination were drawn at the beginning of automated peritoneal dialysis (APD) session and at each instillation of peritoneal dialysate. RESULTS: The mean glucose absorption was 33.7 +/- 10.0% and the AA absorption was 55.2 +/- 13.2% of the infused amount, and the ratio of nonprotein calorie (derived from glucose) to nitrogen (derived from AA) was 115.4:1. The insulin levels returned to normal only three hours after the beginning of APD. The free AA plasma levels were already increased two hours after dinner and remained high for the entire APD treatment because of the continuous absorption of AA from the peritoneum. The BUN levels did not increase despite the supply of AA. CONCLUSIONS: This APD procedure may improve utilization of AA for protein synthesis, as suggested by the lack of increase of the BUN levels with this regimen.

Adolescent↗
PubMed1999

Site I on human albumin: differences in the binding of (R)- and (S)-warfarin.

The binding of drugs known to interact with area I on human serum albumin (HSA) was investigated using a chiral stationary phase obtained by anchoring HSA to a silica matrix. In particular, this high-pressure affinity chromatography selector was employed to study the binding properties of the individual enantiomers of warfarin. The pH and composition of the mobile phase modulate the enantioselective binding of warfarin. Displacement chromatography experiments evidenced significant differences in the binding of the warfarin enantiomers to site I. The (S)-enantiomer was shown to be a direct competitor for (R)-warfarin, while (R)-warfarin was an indirect competitor for the (S)-enantiomer. Salicylate directly competed with (R)-warfarin and indirectly with (S)-warfarin. This behavior was confirmed by difference CD experiments, carried out with the same [HSA]/[drug] system in solution.

Binding Sites↗
PubMed1996

Nutritional status in children receiving chronic peritoneal dialysis.

Chronic peritoneal dialysis (CPD), widely used in uremic children, may have contrasting effects on the nutritional status of patients. Metabolic and nutritional abnormalities due to the combined effects of uremia per se, glucose absorption from the dialysate and catabolic factors, such as protein and amino acid losses into dialysate, poor appetite, and recurrent episodes of peritonitis are the most important. Although CPD allows for fewer dietary restrictions and supplies an extra amount of calories by glucose absorbed with the peritoneal fluid, when protein and energy intakes are assessed the protein intake was almost sufficient or more than that prescribed, whereas the energy intake was low. In CPD children the standard deviation score for weight, height, triceps skinfold thickness, and midarm circumference has been reported as more severely impaired in children less than ten years old. Anthropometric parameters did not worsen during CPD treatment. Plasma proteins and albumin are reported as being low in CPD children. The dietary intake and protein losses have been considered to be the most important determinants of the albumin level in CPD patients. The reported average dialysate losses of free amino acids (AA) during CPD in children vary from 0.02 to 0.03 g/kg/day in different studies. The patterns of plasma AA in CPD is represented by reduced levels of branched chain AA and of other essential amino acids and increased concentrations of some nonessential AA. Several factors may influence plasma AA profile: uremia per se, hormonal alterations, protein and AA losses, and dietary intake. A more specific uremic AA pattern is found in muscle, the largest pool of free AA in the body. Studies on muscle AA in adults on CPD are conflicting: some authors have reported several muscle AA alterations, but others have shown an almost normal pattern. Low valine and leucine muscle levels have been reported in children on CPD.

Adolescent↗
PubMed1996

Protein and calorie intake, nitrogen losses, and nitrogen balance in children undergoing chronic peritoneal dialysis.

We performed 22 nitrogen balance (NB) studies of three days' duration in 19 children (8.7 +/- 3.8 years) on chronic peritoneal dialysis (CPD) for 19.4 +/- 16.4 months. The dietary intakes were assessed by the double weighing method. Total nitrogen, protein, urea, and creatinine were analyzed in the dialysate and urine collected daily. Total nitrogen was also determined in the feces collected over the whole NB study period, using vegetable charcoal as a marker. The protein intake was 1.64 +/- 0.50 g/kg/day, corresponding to 126 +/- 40% of the recommended daily allowance (RDA) for normal children of the same age, and the calorie intake (diet+glucose from dialysate) reached 75 +/- 26% of RDA. Nitrogen losses were: 0.177 +/- 0.052 g/kg/day with peritoneal fluid and urine, and 0.028 +/- 0.018 g/kg/day with feces. The NB, positive in 17 out of 22 studies, ranged from -116 to +167 mg/kg/day (mean 44.0 +/- 66.2 mg/kg/day). A direct and significant correlation between NB and nitrogen intake (g/kg/day) (r = 0.562, p < 0.05) and total calorie intake (cal/kg/day) (r = 0.483, p < 0.05) has been observed. These data confirm the need to ensure in children on CPD an adequate nutritional intake, and further support the efforts to improve calorie intake.

Blood Proteins↗
PubMed1996

Children on continuous ambulatorial peritoneal dialysis: muscle and plasma proteins, amino acids and nutritional status.

The aim of the study was to investigate plasma and muscle amino acid (AA) levels in children on continuous ambulatory peritoneal dialysis (CAPD) and their relationship to various indices of nutritional status. Ten children with a mean age of 6.4 +/- 5.6 yrs were evaluated. Muscle biopsies and venous blood samples were taken after an overnight fast. Muscle samples were obtained from rectus abdominis. Data were compared with those of a control group of 22 children who were undergoing elective surgery. Informed consent was obtained from the parents. The plasma concentration of most of the essential AA (valine, leucine, isoleucine, lysine, methionine and tyrosine) were significantly reduced and the levels of some non essential AA (aspartic acid, glycine, citrulline, 1-3 methihystidine, taurine + alanine) were significantly higher than in the controls. Muscle intracellular free essential AA concentrations, except the low levels of valine and leucine did not differ significantly from values in the controls. Among non essential AA, aspartic acid, glutamic acid and ornitine showed significantly increased intracellular concentrations. No significant correlations were found between plasma and muscle AA concentration and ASP (alkali-soluble protein)/DNA ratio, serum albumin, transferrin, bicarbonate levels and duration of CAPD. Instead, a significant correlation was noted between the muscle ASP/DNA ratio, an indicator of the amount of cell proteins per cell unit, and age (r = 0.714, p < 0.05). Muscle Branched chain AA levels were significantly correlated to body mass index (BMI) (r = 0.648, p < 0.05).

Adolescent↗
PubMed1996

Is the response to rhGH in peritoneal dialysis patients less effective than in patients with chronic renal insufficiency.

Data on the effects of rhGH treatment in children on peritoneal dialysis are limited. In general rhGH therapy seems to be less effective compared with results on patients with chronic renal failure on conservative treatment. Our experience suggests that rhGH can stimulate growth in children on CPD, and that the efficacy of such therapy is reduced after the first year of treatment, although the rhGH is still active.

Child↗
PubMed1994

Muscle and plasma amino acids and nutritional status in kidney-transplanted children.

Nutritional status, assessed by anthropometric and biochemical methods, protein and amino-acid (AA) composition and muscle water were evaluated in 11 kidney transplanted children and in a control group of 10 children with normal renal function who were undergoing elective surgery. Samples of the rectus abdominis muscle were taken when surgery was performed in the control children and when the peritoneal catheter was removed in the transplanted children. The mean time from the transplantation to the study time was 97 +/- 14 days (range 72-114 days). Height was reduced in the transplanted children compared to the controls but skinfold thickness, arm muscle circumference and serum proteins (total protein, albumin, transferrin, pseudocholinesterase) were normal. The body mass index was over the 50 degree percentile in nine of the eleven children. The muscle contents of total, extracellular, and intracellular water, alkali-soluble protein (ASP), DNA and the ASP/DNA ratio were not significantly different in transplanted children from those in the controls. Plasma leucine and taurine levels were significantly decreased, whereas plasma citrulline and alanine levels and the glycine/serine ratio were increased. Muscle threonine, alanine+taurine, glycine and aspartic acid levels as well as the glycine/serine ratio were increased in the transplanted children. Transplanted children show an almost normal muscle AA profile and a plasma AA pattern that seems to be related to the prednisone therapy.

Adolescent↗
PubMed1993

Proteolytic activity and free amino acid concentrations in polymorphonuclear leucocytes.

Polymorphonuclear granulocytes (PMN) are valuable tools for evaluating amino acid (AA) metabolism in nucleated cells, although variations of free amino acid concentrations due to the methods used for the separation of the cells and the procedures used for lysis have been reported. Furthermore, analytical variations in PMN AA concentration may be induced by protease activation during preparation, so that free AA detected in cells could originate from proteolysis other than from the physiological metabolic pathways and transport systems. To study this possibility we measured granulocyte protease activity and AA concentrations in cell suspensions processed with and without the addition of antiproteolytic agents. Granulocyte AA concentrations and protease activity in samples treated with antiproteolytics were 8-15 times lower than in samples processed without antiproteolytics. The use of protease inhibitors throughout the sample preparation is necessary for reliable estimation of free AA in granulocytes.

Amino Acids↗