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Biomedical subjects

R Olivieri

Publications and source records attributed to R Olivieri.

17 recordsLinked to original sources
PubMed1995

Cyclodextrins for growth of Helicobacter pylori and production of vacuolating cytotoxin.

Growth of Helicobacter pylori in liquid culture requires the addition of media supplements that often interfere with subsequent purification of bacterial antigens. In order to determine whether cyclodextrins can substitute for conventional H. pylori growth supplements, we cultured H. pylori in the presence of five commercially available cyclodextrins. The effect of these compounds on the production of the vacuolating cytotoxin antigen was evaluated. Several cyclodextrins supported flourishing growth and permitted the consistent production of vacuolating cytotoxin. These data suggest that Brucella broth supplemented with cyclodextrins is an improved medium for bacterial culture and industrial production of H. pylori antigens.

Antigens, Bacterial↗
PubMed1995

Helicobacter pylori cytotoxin: importance of native conformation for induction of neutralizing antibodies.

We have attempted to express the Helicobacter pylori vacuolating cytotoxin in Escherichia coli. Although the 95-kDa VacA polypeptide was expressed abundantly, it completely lacked any biological activity. In addition, this material failed to induce neutralizing antibodies after immunization of rabbits. In contrast, highly purified high-molecular-mass cytotoxin from the supernatant of H. pylori cultures was active in a HeLa cell assay and effectively induced a neutralizing response in rabbits. Neutralizing sera were shown to contain a high proportion of antibodies which recognized conformational epitopes found only on the native toxin. The data indicate that toxin-neutralizing epitopes are conformational and that potential vaccines based on the cytotoxin may benefit from the use of the intact molecule.

Animals↗
PubMed1995

Construction of nontoxic derivatives of cholera toxin and characterization of the immunological response against the A subunit.

Using computer modelling, we have identified some of the residues of the A subunit of cholera toxin (CT) and heat-labile toxin that are involved in NAD binding, catalysis, and toxicity. Here we describe the site-directed mutagenesis of the CT gene and the construction of CT mutants. Nine mutations of the A subunit gene were generated. Six of them encoded proteins that were fully assembled in the AB5 structure and were nontoxic; these proteins were CT-D53 (Val-53-->Asp), CT-K63 (Ser-63-->Lys), CT-K97 (Val-97-->Lys), CT-K104 (Tyr-104-->Lys), CT-S106 (Pro-106-->Ser), and the double mutant CT-D53/K63 (Val-53-->Asp, Ser-63-->Lys). Two of the mutations encoded proteins that were assembled into the AB5 structure but were still toxic; these proteins were CT-H54 (Arg-54-->His) and CT-N107 (His-107-->Asn). Finally, one of the mutant proteins, CT-E114 (Ser-114-->Glu), was unable to assemble the A and the B subunits and produced only the B oligomer. The six nontoxic mutants were purified from the culture supernatants of recombinant Vibrio cholerae strains and further characterized. The CT-K63 mutant, which was the most efficient in assembly of the AB5 structure, was used to immunize rabbits and was shown to be able to induce neutralizing antibodies against both the A and B subunits. This molecule may be useful for the construction of improved vaccines against cholera.

Animals↗
PubMed1993

Growth of Helicobacter pylori in media containing cyclodextrins.

We show that solid and liquid media, supplemented only with cyclodextrins and free of blood and its derivatives, support the growth of Helicobacter pylori. These media can be used for primary isolation of the bacteria from biopsy samples, routine laboratory growth, and large-scale industrial fermentation.

Bacterial Proteins↗
PubMed1993

Ultrasound therapy of chronic arm lymphedema after surgical treatment of breast cancer.

The treatment of chronic arm lymphedema following axillary dissection for breast cancer is still a therapeutic challenge. To examine other treatment options, we undertook a pilot study on the efficacy of ultrasound therapy (UST) in management of these patients. Fifty patients with post-surgical arm lymphedema and without regional irradiation underwent ultrasound treatment (2 cycles at 4 month intervals) and the results were compared up to 1 year with 100 other patients treated by standardized mechanical pressure therapy (MPT) using a pneumatic pump. In this report we evaluate 96 patients who have been followed after 1 year, 31 of whom belong to UST group and 65 to the MPT group. UST did not show a statistically significant difference in whole arm reduction of lymphedema although there was initially a greater reduction in size after the first 4 months of treatment. The addition of an elastic sleeve did not improve lymphedema in either group. Advantages of UST were an overall shorter length of treatment, a tendency to greater softening of the arm, patient satisfaction by avoidance of an uncomfortable and constrictive device and better relief of osteomyofascial pain, greater scapulohumeral motion, and less intercostobrachial pain-dysesthesia.

Arm↗
PubMed1992

Cellular pertussis vaccine containing a Bordetella pertussis strain that produces a nontoxic pertussis toxin molecule.

Bordetella pertussis 165-9K/129G, which produces a nontoxic form of pertussis toxin (PT), was used to prepare a whole-cell diphtheria-tetanus-pertussis (DTP) vaccine. The in vivo potency and the serological response induced by this vaccine were comparable to those of the conventional DTP vaccine which contains active PT. The toxic activities induced by PT such as leukocytosis, histamine sensitivity, and potentiation of anaphylactic reactions, which are present in the conventional DTP vaccine, were absent in the new vaccine. These results suggest that the introduction of a whole-cell vaccine containing B. pertussis 165-9K/129G would induce the same immunity as the conventional vaccine and would avoid the administration of a harmful toxin to children.

Animals↗
PubMed1976

Microbial degradation of oil spills enhanced by a slow-release fertilizer.

The improved cleanup of marine oil spills by stimulating biodegradation through the use of a slow-release fertilizer is reported. A paraffin-supported fertilizer containing MgNH4PO4 as active ingredient was developed and evaluated in laboratory and field experiments using quantitative infrared spectrometry and chromatographic techniques. The biodegradation of Sarir crude oil in the sea was considerably enhanced by paraffin-supported fertilizer. After 21 days 63% had disappeared as compared to 40% in the control area.

Bacteria↗
PubMedDate not supplied

[Illness behaviour: the influence of age, sex and socio-economic status (author's transl)].

Some results of a study done in 1975/76 in Basle are presented (N=422 people working in administrative and industrial firms). Generally medicine takers are to be found in a high percentage already in the group with little symptoms. On the other side many of those reporting a high number of symptoms do not consult a physician. The number of symptoms reported is higher with progressive age, women and lower socio-economic status. Nevertheless we do not find an increase of consultations with a physician in the same direction.

Adult↗