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M D Vancetto

Publications and source records attributed to M D Vancetto.

6 recordsLinked to original sources
PubMed1997

Specific peptides of casein pancreatic digestion enhance the production of tetanus toxin.

Casein pancreatic digest is the basic bacterial growth medium used for diphtheria, botulinum and tetanus toxin vaccine production. It is known that the variation in the peptide content of the casein digest directly affects final toxin yields. In this study, the identification and sequences of eight peptides, four to eight amino acids in length, of casein pancreatic digestion, which seem to be involved in the enhancement of tetanus toxin production, are described. They all contain one or two residues of proline/molecule and a predominance of hydrophobic amino acid residues. The most active peptides show a general structure of Pro-aromatic-Pro, and this pattern resembled the motif displayed by bradykinin-potentiating peptides found in snake venoms. By analogy with the mechanism of bradykinin potentiation through inhibition of the proteolytic degradation of bradykinin, it is suggested that the six peptides identified here could protect the tetanus toxin from proteolysis, once secreted by the bacteria.

Animals↗
PubMed1995

Neutralization of the effect of Crotalus durissus terrificus venom by gangliosides.

We determined the ability of a mixture of gangliosides (16% GD1b, 19% GT1b, 21% GM1, 40% GD1a) to neutralize the effect of Crotalus durissus terrificus (Cdt) venom in vitro and in vivo. Protection was indicated by the absence of muscular contractions, hind limb paralysis or death of BALB/c mice (16-18 g) after receiving Cdt venom (1 microgram Cdt venom containing 0.6 microgram protein) at the doses indicated. A dose of Cdt venom above 0.9 microgram (ip) or 1 microgram (im) induced muscular contraction and above 1.2 micrograms (ip) or 5.5 micrograms (im) the venom induced muscular contraction and hind limb paralysis. Cdt venom above 2.5 micrograms (ip) or 9 micrograms (im) induced all these symptoms and 95 to 100% death in experimental animals. The lethal dose 50% of the Cdt venom used was 8 micrograms (im) and 1.5 micrograms (ip). In in vitro studies, 4 mg gangliosides neutralized the effect of up to 1.5 micrograms Cdt venom. Quantities as low as 0.2 mg gangliosides were capable of neutralizing 0.9 microgram of Cdt venom in vitro. Intramuscular treatment with 1 mg gangliosides performed 60 min after the intramuscular injection of 5 micrograms Cdt venom protected 100% of the animals. In contrast, no protection was achieved with intraperitoneal treatment with gangliosides. The data show that gangliosides were effective in neutralizing the toxic effects induced by Crotalus durissus terrificus venom both in vitro and in vivo and that post-exposure intramuscular treatment with gangliosides could protect animals experimentally inoculated with the venom.

Animals↗
PubMedDate not supplied

Development and validation study for the chromatographic purification process for tetanus anatoxin on Sephacryl S-200 High Resolution.

The tetanus purified anatoxin is used in the preparation of multiple immunoprophylactics. WHO (World Health Organization) specifies that the tetanus anatoxin must exhibit a degree of purity greater than or equal to 1,000 Lf/mg protein nitrogen (PN). Today liquid chromatography is a well established technique for the purification of tetanus anatoxin and several different methods are used in production scale. On a small scale, we purified tetanus anatoxin on Sephacryl S-200 High Resolution (gel filtration) and we obtained a successful high-yield purification. On the basis of these results, by combining conventional tangential flow filtration (TFF) at 50,000 N.M.W.L. (Nominal Molecular Weight Limit) ultrafiltration membrane with gel filtration on Sephacryl S-200 High Resolution, we have been able to purify 14 lots of tetanus anatoxin using the Bioprocess System (Amersham Pharmacia Biotech) to a large scale operation. Using this method, 77,401,332 doses of tetanus toxoid were prepared in 14 consecutive lots, supporting the reproducibility and reliability of the method presented here.

Acrylic Resins↗