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Biomedical subjects

F Locatelli

Publications and source records attributed to F Locatelli.

At least 289 records · Page 16Linked to original sources
PubMed1996

Ionic dialysance as a method for the on-line monitoring of delivered dialysis without blood sampling.

BACKGROUND: It is well known that the difference between prescribed and delivered dialysis doses greatly affects the morbidity and mortality of dialysed patients. The on-line monitoring of delivered dialysis is therefore of paramount importance. Recently, a conductivity-based method for determining Kt/V on routine basis has been proposed. METHODS: The study was performed using a specially designed module (Biofeedback Module, COT, Hospal) which, when connected to a dialysis monitor, automatically determines effective ionic dialysance (ID). During three consecutive dialysis sessions, administered to each of eight patients at the same depurative efficiency, we determined Kt/V by using mean effective ionic dialysance and by assuming, as suggested, that urea distribution volume corresponded to 55% of body weight. This method was compared with the gold standard of the direct quantification method. The Kt/V was also calculated by using mean effective ionic dialysance and the volume of urea distribution derived from anthropometric parameters. RESULTS: The Kt/V determined by using mean effective ionic dialysance and by assuming that urea distribution volume corresponded to 55% of body weight was heavily underestimated (-22%). This difference was due to both the overestimate of urea distribution volume (+17%) and underestimate of effective urea clearance (KUeff) (-11%). The mean Kt/V calculated on the basis of ionic dialysance and anthropometric volume was also underestimated (-23%) since this volume was overestimated (+17%). Nevertheless, ionic dialysance and urea clearance proved to be closely correlated (r2 = 0.89) so that effective urea clearance can be derived according to: Kueff = ID x 0.865 + 39.89. CONCLUSIONS: In steady-state patients, once urea distribution volume has been correctly determined by means of direct quantification, effective urea clearance can be easily derived from ionic dialysance and Kt/V calculated on-line at each session, without blood sampling or any additional costs.

Evaluation Studies as Topic↗
PubMed1996

IgM antibody response to hepatitis C virus in end-stage renal disease.

BACKGROUND: In HBV infection, as in other viral diseases, antibodies of the IgM class are associated with acute or ongoing infection. In contrast, the significance of this antibody in HCV infection is unclear and data regarding end-stage renal disease (ESRD) patients are lacking. METHODS: We tested sera from 78 ESRD patients (66 chronic dialysis patients, 12 renal allograft recipients) showing anti-HCV IgG antibody, for serum anti-HCV IgM core antibody. A specific solid-phase enzyme-linked immunoassay (HCV IgM EIA, Abbot) was used. In all patients serum HCV RNA was detected by RT-PCR technique, with primers from the 5' untranslated region of the viral genome. RESULTS: Prevalence of anti-HCV IgM core antibody was 22% (17/78). We observed association between prevalence of anti-HCV IgM core antibody and frequency of HCV RNA in the serum. Thus 15 of 45 (33%) sera containing HCV RNA also contained anti-HCV IgM, while two of 33 (6%) HCV RNA negative sera showed anti-HCV IgM core antibody (P = 0.01). There was a significant relationship between absorbance values of anti-HCV IgM core antibody and NS3 (P = 0.01), NS5 (P = 0.04), and core (P = 0.0001) reactivity in RIBA-2 and RIBA-3 assays. Optical density values of anti-HCV IgM were significantly associated with the number of reactive bands in RIBA-2 (P = 0.04) and RIBA-3 (P = 0.03) assays. CONCLUSIONS: 22% of ESRD patients with anti-HCV IgG activity showed anti-HCV IgM core antibody in the serum. Anti-HCV IgM activity seems to correlate positively with HCV viraemia in ESRD population. Testing for this antibody may be useful as a serological marker to indicate the presence of ongoing HCV infection.

Adult↗
PubMed1996

Hepatitis C virus genotypes in chronic dialysis patients.

BACKGROUND: Hepatitis C virus (HCV) infection is highly prevalent in dialysis patients. To further characterize HCV infection in this patient population, we studied the distribution of viral genotypes in 55 patients undergoing chronic dialysis treatment with seropositivity for HCV markers. METHODS: Thirty-two of 55 (58%) patients showed HCV RNA in the serum using reverse transcription polymerase chain reaction (RT-PCR) in the 5'-untranslated region (UTR) of the viral genome. HCV genotyping was performed using biotinylated type-specific oligonucleotide probes after hybridization with amplified sample material. RESULTS: HCV subtype 2a was dominant (56%), followed by HCV subtype 1b (31%), type 3 (3%) and 4 (3%). There was no association between demographic or clinical features of this cohort and HCV genotype. Genotype dependence was observed for antibody response toward the NS4 (c 100-3 and 5-1-1) proteins, which was infrequent in genotype 2a carriers compared with genotype 1b (p = 0.004). CONCLUSIONS: HCV subtype 2a was dominant in our cohort of anti-HCV-positive dialysis patients; there was no association between HCV genotypes and demographic or clinical features of patients; the absence of antibody response toward the NS4-related antigens was frequent in genotype 2a carriers and may serve to predict responses to interferon therapy. The relative homogeneity of the viral population in dialysis patients attending our unit suggests a nosocomial transmission of HCV in this clinical setting.

Adult↗
PubMed1996

Antimicrobial activity of human pancreatic juice and its interaction with antibiotics.

Pancreatic juice (PJ) should be a factor of variability in the antimicrobial activity of antibiotics eliminated by the pancreas during pancreatic infections. We studied its effects on the activity of antimicrobial drugs with different mechanisms of action. Samples of pure PJ were collected from 16 patients with stabilized external pancreatic fistulas. The antimicrobial activity of the juice at different concentrations (from 1.25 to 100%) alone and in combination with mezlocillin, imipenem, ceftriaxone, gentamicin, ofloxacin, and ciprofloxacin was studied by a microbiological method (continuous turbidimetric recording of bacterial growth). The human PJ showed dose-dependent antimicrobial activity that increased directly with the concentration. The activity of the antibiotics at bactericidal concentrations were not modified by the PJ, while the combination with subinhibitory concentrations produced the following variable and different effects: (i) additivity with mezlocillin, ceftriaxone, gentamicin, and ciprofloxacin and autonomy (no interaction) with imipenem and ofloxacin against Providencia rettgeri and (ii) additivity with ceftriaxone, ofloxacin, gentamicin, imipenem, and mezlocillin and autonomy with ciprofloxacin against Escherichia coli. In the presence of PJ, fluoroquinolones showed constant positive effects, while beta-lactams showed more variable antimicrobial activity. Antibiotic concentrations and PJ pharmacodynamics are the main factors determining the final effect of the interaction in vitro. These results may be useful in choosing antibiotics for the treatment of pancreatic infections when they are supplemented with the pharmacokinetic data for each drug.

Adult↗
PubMed1996

Low-dosage ibopamine treatment in progressive renal failure: a long-term multicentre trial.

A multicentre trial (11 nephrology centres) was carried out to test the effects of ibopamine, an orally active dopamine-like drug, on the progression of chronic renal failure. For a 2-year period 189 chronic renal failure patients (serum creatinine level 1.5-4.0 mg/dl) were observed. They were homogeneous for basic nephropathy, degree of residual renal function, blood pressure, and proteinuria. The patients were randomly divided into two groups: 96 took ibopamine at a dosage of 100 mg/day (group A) and 93 served as controls (group B). All were on a low-protein diet (mean 0.8 g/kg body weight). By the end of the observation period, the rate of decrease of the renal function indexes in time proved significantly slower (1.8 times) in group A than in group B. The survival curves for renal function (pre-established end points were creatinine level increases equal to or > 20% and equal to or > 40% of the basal values) proved significantly better (p < 0.02 and p < 0.002 respectively) in group A than in group B. The mean plasma creatinine values rose by 17% in group A and by 36% in group B. The creatinine clearance decreased by 5% in treated patients and by 14% in the controls. Statistical analysis ruled out any possible centre effect. The trial suggests that low-dosage ibopamine administration may be used as a valid and safe pharmacological adjunct for retarding the progression of renal failure in patients with mild or moderate chronic renal impairment.

Adolescent↗
PubMed1996

Determining the adequacy of sodium balance in hemodialysis using a kinetic model.

The importance of sodium balance avoiding intradialytic cardiovascular instability and interdialytic hypertension and pulmonary edema is well known. An early analytical single-pool kinetic model created to evaluate sodium balance in hemodialysis, using flame photometry to determine plasma and dialysate sodium concentrations, has been shown to have a level of imprecision of +/- 2.8 mEq/l in predicting end-dialysis sodium plasma water concentrations (NaPWt). The ionometric determination of sodium concentrations seems to be more accurate and refers to the activity of the sodium capable of crossing dialysis membranes. On the basis of the theoretical premises of the model mentioned above, we developed a computerized single-pool kinetic model which makes it possible to calculate the ionized dialysate sodium activity (NaDI) required to reach a pre-established target of end-dialysis blood sodium activity (NaBI). Thirty-seven non-diabetic and anuric patients undergoing regular thrice-weekly hemodialysis were given their usual dialysis treatment, with NaDI at the usual value for each patient (range 137-147 mEq/l) and kept constant throughout dialysis. At the beginning and end of the session, NaDI and NaBI were measured in quadruplicate by means of a Nova-1 device (Direct Potentiometry, Pabisch Instruments). The validity of this kinetic model was tested by considering the difference between predicted and observed (P-O) NaBI at the end of dialysis [(t)]. P-O NaBI(t) was -0.37 +/- 0.42 mEq/l, which was statistically different from 0 (p < 0.001). When P-O NaBI(t) was plotted against ONaBI(t), it was more negative at the higher values of ONaBI(t). P-O intradialytic sodium removal (Nag) was -12.5 +/- 17.8 mEq/session, which was also statistically different from 0 (p < 0.001). The imprecision of this kinetic model was less than 0.84 mEq/l, as estimated by doubling the SD of P-O NaBI(t) (0.42 = 0.84 mEq/l). Although the reasons for its inaccuracy especially at higher ONaBI(t) values remain to be clarified, these data are the expression of a satisfactory clinical model.

Aged↗
PubMed1996

Intradialytic calcium balances with different calcium dialysate levels. Effects on cardiovascular stability and parathyroid function.

It has been shown that calcium carbonate (CaCO3) is an effective phosphate binder which is less toxic than Al(OH)3. However, given that its use with standard calcium dialysate (CaD) levels may lead to hypercalcemia, a decrease in CaD levels has been proposed. The aim of the present study was to elevate the acute clinical and biochemical consequences of a lowering of CaD in HD patients. Dialysate composition was otherwise the same. (1) Blood pressure levels (BP) during short hemodialysis were measured in a group of 12 patients who underwent alternate hemodialyses with dialysate calcium of 1.75 and 1.25 mmol/l. (2) Ca2+ and PTH kinetics during short hemodialysis were studied in a group of 6 patients who were sequentially treated with 1.75 and 1.25 mmol/l CaD. The results show: (1) that cardiovascular stability in chronic HD patients during short HD sessions with low CaD (LCaD) may be good; (2) that a single treatment with standard CaD (SCaD) produces positive calcium balances (JCa2+) with Ca2+ plasma increase and PTHi inhibition at the end of HD sessions; during HD with LCaD there were neutral mean JCa2+ and no changes in post-dialysis mean Ca2+ and PTHi plasma levels; furthermore 2 patients showed a small PTHi increase during HD with LCaD and neutral JCa2+ because of a high positive bicarbonate balance during HD. In conclusion, as with several aspects of dialysis treatment, dialysate calcium levels should also be individualized to avoid hypercalcemic crises or PTHi stimulation.

Acid-Base Equilibrium↗
PubMed1996

Recombinant hepatitis B vaccine use in chronic hemodialysis patients. Long-term evaluation and cost-effectiveness analysis.

The prevalence of hepatitis B virus (HBV) infection in our unit was 45% (86/190); there were 77 (40.5%) and 9 (4.7%) patients with previous and persistent HBV infection, respectively. Recombinant hepatitis B vaccine was given to 118 chronic HD patients with a regimen of 3 double doses administered intramuscularly at 0, 1 and 2 months, obtaining a seroprotection rate of 67% (79/118), 57% (45/79) being high responders. At month 24, 78% (40/51) maintained protective levels of anti-HBs, 45% (18/40) of them being high responders. There was a statistically significant difference between responder and non-responder patients with regard to nutritional parameters such as serum total proteins and mean levels of transferrinemia. The number of diabetic patients was significantly increased in the nonresponder group. Patients with persistent antibodies ('persistent responders') were younger and had a shorter duration of HD treatment compared to those responders who rapidly lost anti-HBs ('transient responders'). Serological positivity for antibodies against hepatitis B core antigen significantly facilitates the decrease of anti-HBs antibodies over time. We detected seven episodes of HBV infection among HD patients at our unit before the beginning of the vaccination program. On the contrary, there were no episodes of HBV infection among responder vaccinees during the 24-month follow-up period. After the initial cost of vaccination, a savings of US$ 3,272 per year was realized by the elimination of frequent serologic screening of vaccine responders.

Adolescent↗
PubMed1996

Virological and histological features of hepatitis C virus (HCV) infection in kidney transplant recipients.

BACKGROUND: Although there are some reports regarding prevalence of anti-HCV antibodies in kidney transplant patients, there are scarce data about viraemia, genotyping and liver histology of HCV infection in kidney transplant recipients. METHODS: We studied the prevalence of anti-HCV antibodies by second-generation screening and confirmatory assays in a cohort of 73 renal allograft recipients. All patients were tested for serum HCV RNA using reverse transcription polymerase chain reaction in the 5'-untranslated region (UTR) of the viral genome. HCV RNA positive patients were subjected to genotype analysis using biotinylated type-specific oligonucleotide probes after hybridization with amplified sample material. Eleven of 73 patients showing raised aminotransferase levels underwent hepatic biopsy. RESULTS: Fifteen of 73 (20%) patients were determined anti-HCV positive. Eleven of 73 (15%) showed detectable serum HCV RNA; no viraemic, seronegative patients were identified. Genotyping showed that HCV subtype 2a was dominant (64%), followed by HCV subtypes 1b (27%) and 1a (9%). Six of 11 (54%) HCV RNA patients and 12 of 62 (19%) HCV RNA negative patients showed raised aminotransferase levels (P = 0.03). Liver biopsies showed histological features of chronic hepatitis with mild or moderate degrees of activity. CONCLUSIONS: The prevalence of anti-HCV antibodies and HCV viraemia was 20% and 15% respectively; there was a good association between anti-HCV anti-bodies and HCV viraemia; hepatic enzyme levels were good indicators of ongoing HCV infection; HCV subtype 2a was prevalent; liver histology showed histological characteristics of chronic hepatitis with mild or moderate degrees of activity.

Adult↗
PubMed1996

Use of recombinant human granulocyte colony-stimulating factor in children given allogeneic bone marrow transplantation for acute or chronic leukemia.

The role of recombinant human granulocyte colony-stimulating factor (rHuG-CSF) in myeloid recovery of children given an allogeneic bone marrow transplant (BMT) from an HLA-identical sibling for acute leukemia was evaluated in a retrospectively historically controlled study, involving 20 consecutive treated patients and 30 historical controls. In order to investigate the efficacy of rHuG-CSF in patients given a matched unrelated BMT with methotrexate as part of graft-versus-host disease (GVHD) prophylaxis, we also analyzed the kinetics of engraftment in eight further children with acute or chronic leukemia, transplanted using a volunteer donor. Patients were treated with 5 micrograms/kg/day of rHuG-CSF by 1-h intravenous infusion from day +5 until the absolute neutrophil count (ANC) was > or = 2 x 10(9)/l. No adverse effect related to treatment was observed in any patients. Children transplanted from an HLA-identical sibling and treated with rHuG-CSF reached an ANC count greater than 0.5 x 10(9)/l, 1 x 10(9)/l and of 2 x 10(9)/l in a significantly shorter time than the control group (day +9, +10 and +12, vs day +15, +22 and +29, respectively). An accelerated granulocyte production was also observed in patients receiving an unrelated transplant after a GVHD prophylaxis schedule including methotrexate, the median time to neutrophil recovery above 0.5 x 10(9)/l, 1 x 10(9)/l and 2 x 10(9)/l being +14, +15 and +17 days, respectively. In comparison to historical controls, all rHuG-CSF-treated patients had fewer days of fever, of antibiotic therapy and, only for children with HLA-compatible siblings, of hospitalization, whereas in the three groups the duration and severity of mucositis were comparable. No difference between the rHuG-CSF-treated patients and the historical controls given BMT from HLA-identical sibling was seen with regard to incidence of acute or chronic GVHD, relapse rate and actuarial event-free survival at day +100 and 1 year after transplantation. Our data suggest that in children given allogeneic BMT for acute or chronic leukemia, rHuG-CSF reduces duration of neutropenia, without increasing the rate of relapse or the incidence and severity of GVHD.

Adolescent↗
PubMed1996

Unrelated donor marrow transplantation: initial experience of the Italian bone marrow transplant group (GITMO).

From 1 September 1988 to 30 September 1993, a search for an unrelated donor (URD) was started for 633 Italian patients. Eighty-five of them (13%) were transplanted. Despite the introduction of more strict criteria for the selection of compatible donors, the percentage of patients who reached transplant increased significantly after December 1992. For patients who started a search before and after January 1993, respectively the probability of transplant by 8 and 16 months from search activation was 4 and 10%, compared to 22 and 37% (P = 0.0001). The average intervals between search activation and graft were 15 and 8 months respectively, for the first and second group (P = 0.0001). Data of 75 consecutive transplants performed up to March 1994 were analyzed. Actuarial 2-year survival was 15% for patients grafted before 1992 and 40% for those grafted after January 1992. In this latter period, survival of patients with malignant and non-malignant disorders was 32 and 67%, respectively. In univariate analysis, patients younger than 16 years (P = 0.01), patients grafted after 1992 (P = 0.01) and patients receiving the marrow from a 6-antigen matched donor (P = 0.01) showed a higher survival probability. Multivariate analysis did not show any difference, probably due to the low number of patients and to short follow-up. The adoption of stricter and more accurate HLA-matching criteria and the consequent reduction of deaths related to acute GVHD were the main reasons for the improvement of survival observed in patients grafted after 1992.

Adolescent↗
PubMed1996

G-CSF in an infant donor: a method of reducing harvest volume in bone marrow transplantation.

We report the case of a 4-year-old female with high-risk ALL in first CR who received a BMT from an 11-month-old matched sibling treated with G-CSF in order to obtain an adequate number of mononuclear cells in a limited volume of bone marrow. The absence of toxicity, efficacy of the procedure and quality of the post-transplant clinical outcome suggest such treatments are feasible and useful to overcome problems caused by donor age and/or body weight. In view of this experience we demonstrate how such an approach leads to a notable reduction in risks and in bone marrow donation costs.

Bone Marrow Transplantation↗
PubMed1996

Survival of diabetic patients on peritoneal dialysis or hemodialysis.

Our objective was to analyze the survival of diabetic patients on renal replacement therapy and to compare their survival on extracorporeal and on peritoneal dialysis. All data regarding diabetic patients admitted to dialysis between 1 January 1983 and 31 December 1993 were collected by means of individual patient questionnaires sent to all of the 44 regional Renal Units (100% answers) of Lombardy, Italy. Cox proportional hazards model, stepwise procedure, was applied in order to select the covariates significantly associated with survival. Age (at baseline), sex, type of diabetes, initial modality of treatment (hemodialysis or peritoneal dialysis), and initial clinical risk factors (malignancies, serious heart disease, vascular disease, cirrhosis of the liver, cachexia) were considered. Descriptive analysis of survival was performed using the Kaplan-Meier technique. The survival of all diabetic patients (895) was 86.5% at one year, 52% at three years, and 34% at five years. The main causes of the 488 deaths of diabetic patients were cardiovascular diseases (56%), cachexia (18%), and infections (11%). The relative death risk of patients on peritoneal dialysis versus those on hemodialysis, after taking into account the main comorbid conditions, did not significantly differ from 1, as estimated by the Cox proportional hazards regression model. Five-year survival of diabetic patients was 34%, and no differences were found between peritoneal dialysis and hemodialysis as far as mortality is concerned.

Adult↗
PubMed1996

Autologous bone marrow transplantation for extramedullary relapse in childhood leukemia. The AIEOP Group and the FONOP. Italian Association of Pediatric Hemato/Oncology.

The role of autologous bone marrow transplantation (ABMT) in childhood ALL after an isolated extramedullary (IE) relapse is controversial. Between December 1984 and November 1995, 52 children underwent ABMT because of an IE relapse. The data were stored in the AIEOP-BMT Registry. Thirty four children were transplanted in 2nd CR; eighteen > 2nd CR. The median duration of 1st CR was 24 (range 3-69) and 18 (range 3-59) months, respectively. The median interval from last CR to ABMT was 6 (range 1-28) and 3 (range 1-81) months, respectively. The 5 year EFS for patients transplanted in 2nd CR was 67.7%, while the 3 year EFS for patients in > 2nd CR was 16.7%. In conclusion, ABMT was an effective treatment in early IE relapse only if performed in 2nd CR.

Adolescent↗