Abstract: Immunologically active polypeptides constituted, towards the N-terminated end, by an Asn-Val-Asp-Pro-Asn-Ala-Asn-Pro sequence repeated three times and, towards the C-terminated end, by at least three quadruplets with an Asn-Ala-Asn-Pro sequence, linked with each other by means of an amidic bond between the end proline of the first sequence, and the initial asparagine of the first quadruplet.Said polypeptides reproduce nearly exactly the sequential structure of the circumsporozoite protein of P. falciparum, and are useful for the preparation of antimalarial vaccines and of diagnostic kits for the detection of antisporozoite antibodies in clinical samples of malariated persons.

Abstract: New partially retro-inverted tuftsin analogues of general formula I ##STR1## wherein R represents the side-chain of the amino acids threonine, methionine or leucineR.sup.1 represents the side-chain of the amino acids lysine or arginineR.sup.2 is hydrogen or a metabolically labile acyl group,all the asymmetric carbon atoms are either of the S- or R-configuration, or, alternatively, the first, third, and fourth asymmetric carbons, starting from the N-terminal residue, are of the S-configuration while the second one is of the R- or (R,S)-configuration, and the corresponding pharmacologically acceptable salts, esters and amides. The new compounds which share the same pharmacological properties of tuftsin, are much more stable toward the enzymatic degradation than the parent molecule.

Abstract: New decapeptides having hypotensive action are disclosed, which can be defined by the formula:GLp-Leu-Trp-Pro-X-Pro-Y-Z-Pro-Pro-OH (I)wherein:X=Arg or OrnY=His or GlnZ=Ile or Valwith the following limitations:whenX=Arg:Y=HisZ=Val;whenX=Orn:Y=GlnZ=Ile;or, whenX=Orn:Y=HisZ=Valand pharmaceutically acceptable salts, amides of alkyl esters thereof.

Abstract: Pharmacologically active tripeptides, with at least a retro-inverted peptidic bond, definable by means of the following general formulae: ##STR1## their pharmaceutically acceptable salts, esters or alkyl amides, whereinR.sub.1 represents a hydrogen atom, an alkyl group with a maximum of 7 carbon atoms, an aryl, hydroxyalkyl or hydroxyarylalkyl, guanidylalkyl, amino-alkyl, alkyl-oxy-alkyl, acylamino-alkyl, imidazolylalkyl, indolyl-alkyl, mercapto alkyl, alkylmercaptoalkyl, carbamoyl-alkyl, carboxyalkyl, alkyl-carbamoylalkyl or alkyloxy-carbonylalkyl group;R.sub.2 represents a ##STR2## group, Z is an OH, OR.sub.3, NH.sub.2, NHR.sub.3 group, whereinR.sub.3 represents an alkyl group with a number of carbon atoms comprised within the range of from 1 to 10.

Abstract: Hexapeptides with vasodilating and hypotensive activity are described corresponding to the formula: ##STR1## wherein:X is a hydrogen atom or an acyl radical R.sub.3 -CO- wherein R.sub.3 is a straight or branched (C.sub.1 -C.sub.7)alkyl group,R.sub.1 and R.sub.2, each independently, represent the side-chain residue of the amino acid glycine (--H), alanine (--CH.sub.3), valine ##STR2## leucine ##STR3## or isoleucine ##STR4## Arg is the abbreviated designation for arginine, Pro is the abbreviated designation for proline, Tyr is the abbreviated designation for tyrosine, and the pharmaceutically acceptable salts, lower alkyl esters and amides thereof, a process for their preparation and the pharmaceutical compositions containing them.

Abstract: Retro-inverted peptides, analogues of Bradykinin Potentiator Pentapeptide (BPP.sub.5a), definable by the general formula (I) ##STR1## useful as antihypertensives and diagnostics.

Abstract: Pharmacologically active, partially retro-inverso, neurotensin-like peptides lasting longer than the natural hormone, corresponding to the formula ##STR1## wherein R.sup.1 and R.sup.2 are straight or branched (C.sub.1 -C.sub.7) alkyl radicals.The new compounds are useful as vasodilating and hypotensive agents.

Abstract: New partially retro-inverso peptides of the following general formula ##STR1## wherein R.sup.1 and R.sup.2 are the same or different and represent, each independently, the side chain of the aminoacid residues present in the naturally occuring peptides, X is --S--Ph or --O--CH.sub.2 --Ph and Z is a hydroxy, alkoxy or amino group, are described as well as a suitable method for their preparation. The new compounds are useful as antihypertensive agents.

Abstract: Peptido-mimetic compounds of hypotensive action definable by the general formula: ##STR1## in which: X represents the pyroglutamic acid residue or a ##STR2## residue where R.sub.2 represents a hydrogen atom, an alkyloxycarbonyl, an arylalkyloxycarbonyl or an acyl group with from 1 to 7 carbon atoms in the linear chain,R.sub.1 represents the aromatic residue of L-phenylalanine, L-tyrosine or L-tryptophan, andZ represents a hydroxyl, hydroxyalkyl, amino or alkylamino group, and their salts and alkyl amides or esters.

Abstract: New retro-inverso peptides and peptide derivatives in the form of analogues of C-terminal hexapeptide fragments of Substance P, which are pharmacologically active, possess prolonged action with time, and are of general formula (I): ##STR1## they being useful as vasedilators.

Abstract: Synthesis of an analogue of the (5-14) decapeptide of equine angiotensinogen partially retro-inverted at the Phe-Phe bond, of formula: ##STR1## The retro-inverso analogue inhibits renin with high resistance to enzymatic degradation, and can be used in the treatment of renin-dependent hypertension.

Abstract: There is provided an analog of the (5-14) decapeptide of equine angiotensinogen which is partially inverted at the Phe-Val bond, and which has the formula ##STR1## This retro-inverso analog inhibits renin with high resistance to enzymatic degradation and it can be used in the treatment of renin-dependent hypertension.

Abstract: This invention relates to new retro-inverso peptides and peptide derivatives in the form of analogues of the bradykinin potentiating peptide (BPP.sub.

Abstract: This invention relates to new retro-inverso peptides and peptide derivatives in the form of analogues and the C-terminal penta and hexapeptide fragments of Substance P, which are pharmacologically active, possess prolonged action with time and are useful as vasodilators, their general formula being: ##STR1##