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Biomedical subjects

R Bucci

Publications and source records attributed to R Bucci.

17 recordsLinked to original sources
PubMed2005

Comparative characterisation of a commercial human chorionic gonadotrophin extracted from human urine with a commercial recombinant human chorionic gonadotrophin.

BACKGROUND: A commercial preparation of recombinant human chorionic gonadotrophin (r-hCG, Ovitrelle) was launched in 2001. Generally, hCG is available in two formats: human chorionic gonadotrophin (u-hCG), derived from the urine of pregnant females, and r-hCG produced by DNA based biotechnology. METHOD: The analytical characteristics of a highly purified u-hCG (Gonasi HP) were assessed and compared, for the first time, with the recombinant derived r-hCG (Ovitrelle). Gonasi HP is produced by extracting and purifying hCG from urine to obtain a specific bioactivity of 5000 IU/mg protein. Ovitrelle is produced via a recombinant derived mammalian cell line and purified to obtain a specific activity of 26 000 IU/mg. RESULTS AND CONCLUSION: It has been documented that commercially available u-hCG preparations can contain a number of urine derived protein contaminants as well as hCG related metabolites. This is also the case for Gonasi HP, where hCG related molecules and other proteins were found to be present, including epidermal growth factor (EGF) and eosinophil derived neurotoxin (EDN). It was also demonstrated that this preparation contained high levels of oxidised hCG. r-hCG was confirmed to be essentially intact hCG, free from contaminant proteins and with very low levels of oxidised hCG.

Chorionic Gonadotropin↗
PubMed2003

Vitamin E-coated membrane dialyzer and beta2-microglobulin removal.

This study was designed to test the removal of beta2-microglobulin (beta2M) in a vitamin E-modified membrane. We investigated in vivo the dialyzer (Excebrane, series EE, 1.8 m2) with respect to hydraulic permeability (Kuf), maximum ultrafiltration rate (UF max), sieving coefficient (Sc), and solute clearances in hemodialysis (HD) and in soft hemodiafiltration (HDF). Kuf was 18.4 ml/h/mmHg, UF max was 75 ml/min, and Sc for beta2M was 0.45. Clearance values at 400 ml/min of Qb in HD were 258 ml/min for urea, 201 ml/min for creatinine, and 135 ml/min for phosphate. In soft HDF, clearances were slightly higher. beta2M clearance was 26 ml/min in HD and 43 ml/min in soft HDF. In conclusion, Excebrane (series EE) procures a soft HDF with an amount of substitution fluid in post dilution mode of over 60 ml/min. Remarkable small solute clearances were obtained when the blood flow was raised to 400 ml/min. A significant reduction of beta2M is demonstrated by HDF.

Antioxidants↗
PubMed1999

Biological characterization of recombinant human follicle stimulating hormone isoforms.

It has been established that follicle stimulating hormone (FSH) circulates in the bloodstream as a heterogeneous population of molecules. Individual FSH isoforms, while displaying identical amino acid sequences, differ in their extent of post-translational modification. As a result of these variations, the FSH isoforms exhibit differences in overall charge, degree of sialic acid or sulphate incorporation, receptor binding affinity and plasma half-life. Taking advantage of the fact that these forms can be separated from each other on the basis of their charge, we have evaluated in rats the metabolic clearance rates of the acidic [with an isoelectric point (pI) </=ISOdia</= 4.8] and the less acidic (pI > 4.8) isoforms of recombinant human FSH (rhFSH) obtained after chromatofocusing. The less acidic isoform group was found to have a faster clearance from the circulation in rats as compared with the acidic isoform group. This finding is in agreement with the lower bioactivity in vivo (as determined by the Steelman-Pohley assay) of the less acidic isoform group, compared with the acidic one. The mass spectra of the two groups of isoforms showed a difference in the sialic acid content thus highlighting the importance of these residues on the in-vivo activity of FSH. Conversely, when the two groups of isoforms were tested in vitro by using the Y1 human FSH receptor (Y1 hFSHR) assay and a reporter gene assay, no significant differences in the biological activities between these preparations were detected when test concentrations were based on mass.

Animals↗
PubMed1996

Hepatitis C virus genotype in anti-HCV-positive hemodialysed patients.

We investigated the influence of hepatitis C virus (HCV) genotypes on the clinical course of HCV infection in a haemodialysis population. In June 1991, a 4 year prospective follow-up programme was implemented in 184 consecutive haemodialysis patients. Alanine aminotransferase (ALT) and gamma glutamine transferase (GGT) were performed every 2 months. When HCV antibody (Ab) (by second-generation ELISA) was positive, it was confirmed by RIBA 2 and HCV RNA amplification by PCR. The pattern of nucleotide sequence variability in the 5' non-coding region was categorized according to Simmonds' genotype classification. Risk factors including blood transfusions were evaluated. The levels of hepatic enzymes in HCV Ab-positive patients were retrospectively studied over a mean period of 11.8 years. ALT and GGT levels were assigned a score for every year of infection (0 = normal, 1 = fluctuating 2 = high levels). Fifty-two patients were HCV Ab reactive (30.4%), eight were RIBA undetermined and 44 were RIBA positive; 40 of these were HCV RNA positive (91%). Twelve patients were HCV RNA negative, suggesting that they had recovered from the infection. Four genotypes were identified: 1b [26 patients (65%)], 1a (one patient), 2 [12 patients (30%)] and 3 (one patient). The genotype distribution was not different from that found in patients with chronic hepatitis C and normal renal function of the same geographical area. Genotype 1b accounted for 75% of the cases before 1985 and an equal prevalence of the two major genotypes was observed after 1985. Patients infected with HCV subtype 1 had normal mean ALT levels, but higher levels in the follow-up period (28 +/- 15.6 IU/l) and higher ALT and GGT personal scores in the retrospective study. Genotype 1 patients had higher mean ALT levels after 6 months. HCV RNA-negative patients had lower ALT levels after 24 months. RIBA pattern could differentiate the patients. Patients with genotype 1 received a higher number of transfusions, while only 50% of HCV RNA-negative patients had been transfused. Our data suggest a worse course of HCV infection in haemodialysis patients infected with HCV subtype 1, but the severity of HCV infection can only be assessed by histology. Transaminases are only loosely correlated with severity.

Antibodies, Viral↗
PubMed1995

Blood volume modeling and refilling rate estimation in hemodialysis by continuous hemoglobin monitoring.

Eleven bicarbonate hemodialyses (HD) of 6 patients under constant ultrafiltration were continuously monitored with an optical Hb-meter, considered to be a marker of blood volume (BV) changes. A theoretical model was fed experimental data for prediction of blood volume and estimation of vascular parameters, and a time course of rate of refilling was extrapolated. The adequacy of the model was very good for the time course of BV prediction (r2 = 0.85-0.95, n = 11) and for plasma protein concentration (r2 = 0.83-0.86, n = 2). Parameters estimated included (mean-DS): filtration coefficient (Cf) = 0.22 (0.16) dl/min*mmHg, transcapillary hydrostatic pressure (DP) = 17.80 (3.44) mmHg and protein concentration of the refilling fluid (Cref) = 0.45 (0.30) g/dl. In conclusion our study has shown that the model chosen fits the observed BV profile well in all cases, thus the Hb data series can be used for BV dynamic modeling and for estimation of vascular parameters.

Adult↗
PubMed1995

Biochemical aspects and clinical perspectives of continuous urea monitoring in plasma ultrafiltrate. Preliminary results of a multicenter study.

We tested a new biosensor for urea monitoring in the ultrafiltrate during PFD in a group of 5 hemodialyzed stable patients. The inspection of the UF-urea profile reflects the dynamical changes of the plasma urea concentration during diffusive dialysis and allows the fitting of the main mathematical models of urea kinetics. The biosensor efficiency was 98.4% on average (SD: 1.5%) at Uf fluxes varying from 45 to 55 ml/min (mean: 51 ml/min; SD: 3.2) and at Uf-urea concentrations varying from 23 to 165 mg/dl. The mean difference between Uf-urea determined by the laboratory method and Uf-urea assayed by the biosensor was -1.07 mg/dl and the 95% confidence interval ranged from -2.01 to 0.13 mg/dl. The mean difference between laboratory plasma urea and Uf-urea from the biosensor was on average -1.9 mg/dl and the estimated limits of agreement with a confidence of 95% were -3.16 and 0.64 mg/dl. Comparison between kinetic models and experimental profiles of plasma urea decrease, evaluations of recirculation and post-dialytic rebound, the role of Kt/V on-line during dialysis were the preliminary clinical applications of this biosensor.

Aged↗
PubMedDate not supplied

[Acute renal failure and thrombotic microangiopathy (TM)].

BACKGROUND: Thrombotic microangiopathy (TM) is a disorder characterized by fibrin formation and platelet aggregation in the small arteries and capillaries. Two main clinical settings are reported in association with this disorder: hemolitic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Both conditions share common findings such as microangiopathic anemia and thrombocytopenia. HUS is more frequent in children and is mainly characterized by renal symptoms, whereas PTT is dominated by neurologic abnormalities. However, in many patients, the clinical distinction between HUS and PTT is not clear; therefore, some authors consider the two syndromes as manifestations of the same entity. In children, the most common cause of HUS is an enteric infection caused by cytotoxin-producing bacteria (mainly Escherichia coli with serotype O157:H7). This toxin--the Shiga toxin--can bind to glomerular endothelial cells and stimulate the production of cytokines and the secretion of von Willebrand factor (vWf). TM may be caused by drugs such as cyclosporin, tacrolimus, mytomicin C, ticlopidine, quinine, and oral contraceptives. It may be associated with disorders of pregnancy (severe pre-eclampsia and postpartum HUS) or with systemic disorders such as systemic lupus erythematosus (SLE), antiphospholipid syndrome, systemic sclerosis, and human immunodeficiency virus (HIV) infection. Abnormalities of the gene of complement factor H have been found in familial HUS and in some sporadic cases of HUS not associated with diarrhea. Factor H abnormalities induce an uncontrolled complement activation that can activate the coagulation cascade. In familial PTT, genetic abnormalities of the cleaving metalloproteinase of fWf ADAMTS 13 have been identified. In other patients with TTP, antibodies inhibiting this enzyme have been found. As a consequence of plasma ADAMTS 13 deficiency, unusually large vWf multimers are produced. This abnormality, in the presence of an increased shear stress, stimulates platelet adhesion and aggregation. CONCLUSIONS: Knowledge of the type of causative abnormality is relevant to a therapeutic approach. Children with diarrheal HUS usually do not benefit from plasma infusion or exchange, whereas in patients with factor H or ADAMTS 13 deficiency procedures that include the administration of the lacking product and removal of the inhibiting or toxic factors, such as ultralarge vWfs, are mandatory. Potentially renal transplantation candidates should be screened for genetic defects to avoid the recurrence of TM in the graft.

Acute Kidney Injury↗
PubMedDate not supplied

[Resistance to antibiotics of bacteria involved in respiratory infections (author's transl)].

The present status of resistance to antibiotics of bacteria involved in respiratory infections is reviewed. Schematically it can outlined as follows. Streptococcus B-haemolyticus as well as Pneumococcus did not change their sensitivity to penicillin, but some strains are now resistant to tetracycline. Streptococcus viridans, Enterococcus and H. influenzae did not change substantially their sensitivity to antibiotics. Staphylococcus aureus is the bacterial species that always poses some problems with regard to antibiotic resistance. Due to the selection of strains penicillinase-producing because of the large use of penicillin, the most part of clinical isolates of staphylococci is now resistant to penicillin. In addition an increased number of strains resistant to the other antibiotics has been registered as soon as they has been introduced in therapy. The resistant strains spread in a particularly rapid way in hospital. The introduction in therapy of penicillinase-resistant penicillins constituted a remarkable advance in therapy of staphylococcal infection. However, there is now a growing number of indications about the emergence of methicillin resistant strains of staphylococci. On the other hand it must be recalled that since 1960 a marked reduction of incidence and mortality in severe staphylococcal infections has been noted. Incidence and mortality of respiratory infections due to Gram-negative bacilli is augmented particularly in connection with a larger use of immunosuppressive and antineoplastic therapies, of particular surgical or reanimation procedures, of intensive courses of antibiotic therapy etc. Emergence of Pseudomonas, Proteus, Serratia, Providencia, etc. infections poses many difficult problems of chemotherapy since these species are scarcely sensitive to antibiotics. Carbenicillin, cephalosporins, sisomicin, tobramycin, amikacin are the more recent drugs that alone or in combination may offer some chances of success in this field.

Anti-Bacterial Agents↗