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D Proietti

Publications and source records attributed to D Proietti.

10 recordsLinked to original sources
PubMed2000

Physicochemical characterisation of the oligosaccharide component of vaccines.

Glycoconjugate vaccines are being developed against Haemophilus influenzae (Hib) and meningococcal Type A and C micro-organisms; they consist of oligosaccharides of intermediate chain length conjugated to the carrier protein CRM (a non-toxic diphtheria toxin mutant). The oligosaccharides can be quantified using specific composition analyses and their structure and identity (and pattern of acetylation) evaluated by use of NMR spectroscopy. The average molecular-size (degree of polymerisation) can be determined using colorimetric assays, qualified by analysis of authentic standards. The molecular-size distribution of these anionic oligosaccharides can be achieved using ion exchange chromatography or application of the rapid and sensitive analytical HPAEC-PAD system (high performance anion-exchange chromatography with pulsed amperometric detection). Preparative ion exchange chromatography permits the isolation of purified oligomers, which can be well-characterised using the methods described above. Molecular size can be confirmed by use of mass spectrometry. These vaccines are semi-synthetic products and therefore their preparation involves several steps of chemical reaction, the detailed physicochemical characterisation of the oligosaccharide-components permits the consistent production of these well-defined glycoconjugate vaccines.

Chemical Phenomena↗
PubMed1999

Size determination of bacterial capsular oligosaccharides used to prepare conjugate vaccines.

We recently described the use of ion exchange chromatography for analysis and the industrial scale preparation of pools of oligosaccharides of intermediate chain length from polysaccharides of Haemophilus influenzae type b (Hib) and Neisseria meningitidis groups A and C. These negatively charged "sized" oligosaccharides are activated and conjugated to the carrier protein (CRM197) to prepare the corresponding glycoconjugate vaccines. Characterization and accurate determination of the degree of polymerization (DP) of the pool of oligosaccharides is essential for the consistent production of these conjugate vaccines. This paper describes the colorimetric assays used for determination of the average DP of the Hib and meningococcal oligosaccharides, and the qualification of these assays achieved by size characterization of the respective oligosaccharides by use of physicochemical methods, including liquid chromatography, mass spectrometry (ionspray) and NMR spectroscopy.

Bacterial Capsules↗
PubMed1998

A competitive enzyme-linked immunosorbent assay for measuring the levels of serum antibody to Haemophilus influenzae type b.

A competitive ELISA method is described for the measurement of total antibodies to the capsular polysaccharide of Haemophilus influenzae type b (HibCPS) in human sera. The competitive method showed an excellent correlation to the radioantigen binding assay (RABA, or Farr assay) and improved correlation of sera with low titers with respect to the more conventional noncompetitive method. Overestimation of samples in the low concentration range was no longer observed with the competitive ELISA method. The free HibCPS competition allowed us to eliminate the day-to-day background variation typical of some sera; thus, only values representing the true anti-HibCPS response were determined. The use of precoated microplates, which could be stored up to 8 months, greatly improved the speed of the procedure. An overall correlation coefficient of 0. 9660 was found when 407 serum samples with a wide variety of anti-HibCPS antibody levels were tested with the competitive ELISA and RABA. The regression line was very close to the ideal line, with a slope of 1.0045 and an intercept of -0.1996. A subset of 96 serum samples representative of all pre- and postimmunization samples was used to compare the competitive ELISA with a previously described ELISA method. The competitive method performed in two laboratories in different countries showed a better correlation with the RABA. The correlation factors were 0.9770 and 0.9816, respectively, while a factor of 0.9547 was found with the previously described noncompetitive procedure, which was better for this method than previously reported (r = 0.917). Therefore, the competitive ELISA is proposed for the assay of anti-HibCPS titers in sera from vaccinated subjects.

Adult↗
PubMed1996

Influence of vehicle composition variations on the in vitro and ex vivo clonazepam diffusion from hydrophilic ointment bases.

A systematic study of formulation factors influencing the release of clonazepam from hydrophilic ointment bases was performed. Diffusion experiments were carried out using both artificial membranes (cellulose nitrate membrane impregnated with lauryl alcohol or isopropylmiristate or vaseline oil) and natural ones (rabbit ear skin). The formulation variables were the percentage of polyethylene glycol 400, polyethylene glycol 6000 and water, and the type of lipophilic component (lauryl alcohol, isopropylmyristate or vaseline oil) added to the vehicle. In vitro and ex vivo results were compared and the best formulation was found, even if it was not possible to establish a precise correlation between the in vitro and ex vivo flux values.

Animals↗
PubMed1982

Extrathecal cavernous hemangioma.

A case of extrathecal cavernous hemangioma, a rare entity, is presented. Some clinical, radiological, and histological features of the lesion are discussed. The unusual dumbbell-like growth of the tumor through an intervertebral foramen is considered, as well as the potential effectiveness of radiation therapy. The literature dealing with spinal hemangiomas and hemangioblastomas is summarized.

Aged↗
PubMedDate not supplied

Severe Legionella pneumophila infection in a patient with hairy cell leukemia in partial remission after alpha interferon treatment.

Legionella pneumonia is an increasingly frequently reported complication in immunocompromised patients, particularly patients with hairy cell leukemia (HCL) in active phase. The most important predisposing factor seems to be the quantitative and qualitative defect of the monocytic-macrophagic system characteristic of HCL. We report a case of severe Legionella pneumophila infection with multisystem involvement in a patient with HCL in stable partial remission obtained after therapy with interferon. In our patient recovery of a normal monocyte count did not protect against a legionella infection, indicating that this pathogen should always be sought in HCL patients even those in clinical and hematologic remission. Early diagnosis and appropriate treatment may reduce the mortality of this serious complication.

Adult↗
PubMedDate not supplied

[Changes in ventilation during use of heat and humidity exchangers].

The Authors studied in 10 patients during mechanical ventilation the effects of the application of heat and moisture exchanger (HME) in the presence of constant TV and frequency. They observed an increase of PaCO2 and PE, CO2 during the use of HME; this is due to Vd/Vt increase. The Authors conclude that it is mandatory to increase the total ventilation when using HME to avoid dangerous levels of hypercapnia.

Adult↗