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Biomedical subjects

M Sela

Publications and source records attributed to M Sela.

At least 181 records · Page 10Linked to original sources
PubMed1980

Antibodies as carriers for oncostatic materials.

Daunomycin conjugates to antitumor antibodies prepared either by direct binding or by binding via dextran retain both the antibody and the drug activity. Thus, the exert specific cytotoxicity in vitro toward tumor cells that the antibodies recognize. The macromolecular conjugates are able to penetrate the cells and concentrate in or on the nuclei. In vivo, the antitumor antibodies accumulate preferentially at the tumor metastases. Daunomycin-antibody conjugates are more active than the free drug in prolongation of survival of mice transplanted with the YAC lymphoma cells.

Animals↗
PubMed1980

Therapeutic effects of maxillofacial prostheses.

Thirty-nine patients with maxillofacial defects were restored by prostheses. A questionnaire was completed both before and after the prosthetic rehabilitation, measuring such psychological aspects as changes in self-image, optimism, and feelings of health. Thirty-three patients were found to respond favorably. Improvement was most pronounced where the facial defect had been caused by trauma (accidents). It was less conspicuous in patients with congenital malformations, whereas oncologic patients' average experimental change was minimal. It is concluded that cancer patients require more than a well-fitting prosthesis for successful rehabilitation.

Adolescent↗
PubMed1980

Effect of cleaving interchain disulfide bridges on the radius of gyration and maximum length of anti-poly(D-alanyl) antibodies before and after reaction with tetraalanine hapten.

The small-angle x-ray scattering of solutions of rabbits IgG antibodies and their derivatives has been investigated. The reduction and alkylation of the native antibody cause a small increase of the molecular parameters, indicating a limited expansion of the molecule. Binding of native antipoly(D-alanyl) antibodies with hapten (80% saturation) causes a significant change of the quaternary structure, expressed by a decrease in the maximum diameter of about 2 nm, of the radius of gyration by 5.5%, and of the volume. The same antibodies, in which the single inter-heavy-chain disulfide bridge was opened by reduction and carboxamidomethylation, do not show any significant decrease in the overall molecular parameters upon reaction with hapten, except for a local structural change in a part of the molecule. These data lend further support to the notion that binding of hapten induces a conformational transition in its specific antibodies and suggest that the opening of the interchain disulfide bridges affects that transition. The dimensions of the intact antibodies calculated from measurements of small-angle x-ray scattering at low concentrations agree closely with those obtained from crystallographic studies.

Alanine↗
PubMed1980

Antiviral response elicited by a completely synthetic antigen with built-in adjuvanticity.

In a previous study we demonstrated that antiviral response against the coliphage MS-2 can be elicited by immunization with a synthetic antigen consisting of a conjugate (P2-A -- L) of a synthetic fragment (P2) of the virus coat protein attached to a synthetic polymeric carrier. The antiviral response was induced when the antigen was administered in complete Freund's adjuvant or when it was administered in incomplete adjuvant, provided that a peptidoglycan was covalently attached to it. In the present study we demonstrate the adjuvant effect of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) in this system. Immunization with a mixture of MDP and P2-A -- L brought about only slight enhancement in the titer of neutralizing antibodies, as compared to the immunization with P2-A -- L in saline. The best results were achieved when the MDP was chemically conjugated to P2-A -- L. This completely synthetic material, when administered in aqueous solution, yielded highly inactivating antiserum with a titer similar to that obtained with complete Freund's adjuvant in the absence of MDP. MDP-P2-A -- L elicited also a humoral immune response to MDP, but with much lower titer than that induced by complete Freund's adjuvant containing P2-A -- L only. It was also observed that the capacity of MDP-P2-A -- L to increase resistance against infection was more than a 100-fold greater than that of unconjugated MDP.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1980

Efficient genetically controlled formation of antibody to a synthetic antigen [poly(LTyr, LGlu)-poly(DLAla)- -poly(LLys)] covalently bound to a synthetic adjuvant (N-acetylmuramyl-L-alanyl-D-isoglutamine).

The synthetic polypeptide antigen poly(LTyr, LGlu)-poly(DLAl)- -poly(LLys)[T,G)-A- -L] was covalently linked to N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), which is the minimal adjuvant-active structure that can substitute for Mycobacteria in complete Freund's adjuvant. When injected in aqueous solution into mice, the completely synthetic conjugate elicited significant antibody responses specific to (T,G)-A- -L, whereas (T,G,)-A- -L alone administered under the same conditions did not lead to antibody production. The conjugate was much more efficient in eliciting (T,G)-A- -L responses than was a mixture of DMP and (T,G)-A- -L. One hundred micrograms of MDP mixed with 10 micrograms of (T,G)-A- -L resulted in production of (T,g)-A- -L-specific antibodies. However, the titers obtained were much lower than those observed with 10 micrograms of the conjugate, MDP-(T,G)-A- -L, which contained less than 1 microgram of MDP. MDP was enhanced when the mixture was administered in incomplete Freund's adjuvant, the adjuvant did not significantly affect the (T,G)-A- -L-specific antibody responses in mice immunized with MDP-(T,G)-A- -L. The isoelectric focusing pattern of antibodies obtained with MDP-(T,G)-A- -L was similar to that obtained after immunization with (T,G)-A- -L in complete Freund's adjuvant. The pattern of high-responder and low-responder mice to (T,G)-A- -L, the immune response to which is genetically controlled, was retained when MDP-(T,G)-A- -L was used as the immunogen. Conjugation of (T,G)-A- -L was creased the immunogenicity of MDP and affected its biological properties. It is thus possible to obtain efficient immune responses to synthetic polypeptide antigens that produce poor reactions when injected in aqueous solution by conjugating them to small molecular weight synthetic adjuvants.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1979

Binding of anti-tumor immunoglobulins and their daunomycin conjugates to the tumor and its metastase. In vitro and in vivo studies with Lewis lung carcinoma.

The present study was undertaken in order to evaluate the possibility of using anti-tumor antibodies as specific carriers of chemotherapeutic drugs to tumor metastases. Xenogeneic and syngeneic antisera were prepared against a metastasizing C57BL tumor, the Lewis lung carcinoma (3LL). The binding of absorbed xenogeneic and syngeneic anti-3LL sera or their Ig fractions to 3LL tumor cells was assayed by direct and indirect methods. Antisera prepared against tumor cells from a local growth reacted to a similar extent with those obtained from the lung metastases. Radioiodinated immunoglobulins from syngeneic antisera injected into mice bearing metastases localized preferentially in metastasis-bearing lungs as compared to several other organs tested. No such preferential uptake was observed either in mice bearing metastases injected with iodinated normal Ig or in normal mice injected with iodinated anti-3LL Ig. This relative accumulation in the metastasis-bearing lungs was observed 3-4 days after the inoculation, when the whole Ig fraction was used, whereas a specific antibody-enriched preparation localized as early as 24 h after injection. Daunomycin--anti-3LL-Ig conjugates were effective inhibitors of tumor cells from both local and the metastatic growths. They were more active than either the free drug or drug conjugates of normal Ig, in in vitro assays.

Animals↗
PubMed1979

Nerve entrapments associated with postmastectomy lymphedema.

Ninety females underwent mastectomy for breast cancer and were thereafter investigated to determine whether nerve entrapments were responsible for some of the disabling symptoms in their arms. The majority of these patients suffered from fullness (edema), numbness, paraesthesia, weakness and pain of the arm on the mastecotmized side. Lymphedema of varying degrees found in 50% of these patients was associated with brachial plexus entrapment and carpal tunnel syndrome (CTS). 28% of the patients has CTS, and 28% suffered from brachial plexus entrapment of the arm on the mastecotmized side, as compared with 8% and 5%, respectively, on the nonoperated side. 12% of the patients suffered from both types of entrapment. Thus we consider that brachial plexus entrapment and carpal tunnel syndrome should be added to the list of complications following mastectomy, with lymphedema playing an active part in their development.

Adult↗
PubMed1979

Cranioplasty with pre-formed methyl methacrylate onlay plates.

The available manufactured plates for cranioplasty of large skull defects are not always satisfactory. Recently we have used preformed methyl methacrylate plates, in combination with Proplast. This plate prepared adjusted and sterilized before the operation is both cosmetically and mechanically satisfactory.

Adult↗
PubMed1979

Change in specificity of antibodies to a random synthetic branched polypeptide in mice tolerant to its ordered analogs.

The crossreactivity between the random synthetic polypeptide antigen, (Tyr,Glu)-poly(DLAla)- -poly(Lys), and its ordered sequence analogs, (Tyr-Tyr-Glu-Glu)-poly(DLAla)- -poly(Lys) and (Tyr-Glu-Tyr-Glu)-poly(DLAla)- -poly(Lys), has been studied on the level of tolerance induction. Induction of tolerance to the random (Tyr,Glu)-poly(DLAla)- -poly(Lys) affected the response of the tolerant mice to the homologous antigen as well as to (Tyr-Tyr-Glu-Glu)-poly(DLAla)- -poly(Lys), which was shown previously to represent the major determinant of (Tyr,Glu)-poly(DLAla)- -poly(Lys). In contrast, these mice responded with high antibody titers to the hardly crossreacting (Tyr-Glu-Tyr-Glu)-poly(DLAla)- -poly(Lys). Mice tolerant to the ordered peptide antigen (Tyr-Glu-Tyr-Glu)-poly(DLAla)- -poly(Lys) did not respond to the homologous polypeptide; however, their immune response to either (Tyr-Glu)-poly(DLAla)- -poly(Lys) or (Tyr-Tyr-Glu-Glu)-poly(DLAla)- -poly(Lys) was not affected. Mice that were tolerant to (Tyr-Tyr-Glu-Glu)-poly(DLAla)- -poly(Lys) responded well to (Tyr-Glu-Tyr-Glu)-poly(DLAla)- -poly(Lys). Furthermore, these mice produced high antibody titers after immunization with the random (Tyr,Glu)-poly(DLAla)- -poly(Lys). However, the antibodies produced were not specific to the major determinant of (Tyr,Glu)-poly(DLAla)- -poly(Lys), namely, Tyr-Tyr-Glu-Glu, but were directed to minor determinants of the random polypeptide, including Tyr-Glu-Tyr-Glu, which are not immunopotent when nontolerant mice are immunized with (Tyr,Glu)-poly(DLAla)- -poly(Lys). Thus, whereas antigenic specificity reflects itself also at the level of tolerance induction, the animals that had been made tolerant are capable of responding to previously silent antigenic determinants.

Animals↗
PubMed1979

Enhancement of certain biological activities of muramyl dipeptide derivatives after conjugation to a multi-poly(DL-alanine)--poly(L-lysine) carrier.

N-Acetylmuramyl-L-Ala-D-Glu-NH2 (muramyl dipeptide) and several of its derivatives are effective immunoactivators that can enhance nonspecific resistance to infection but can also elicit fever. In contrast, one of its stereoisomers, N-acetylmuramyl-D-Ala-D-Glu-NH2, is devoid of both these activities. Our present report demonstrates that macromolecularization of muramyl dipeptide by attachment of several units to a multi-poly(DL-Ala)-poly(L-Lys) carrier potentiates both its pyrogenic and its immunostimulant activity. This branched polymer has been extensively used as carrier to various haptens. Surprisingly, inactive N-acetylmuramyl-D-Ala-D-Glu-NH2, after conjugation under the same conditions, becomes capable of increasing nonspecific immunity although its lack of pyrogenicity is not greatly modified. Moreover, the N-acetylmuramyl-D-Ala-D-Glu--NH2 conjugate remains devoid of adjuvant, sensitizing, or eliciting activity.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1979

Effect of toothbrushing with a fluoride-free and fluoride-containing dentifrice on oral hygiene and number of leukocytes in the gingival fluid.

The number of leukocytes in the gingival exudate and the oral hygiene index during toothbrushing with a fluoride-free and fluoride-containing dentifrice was investigated in humans during a 3-month period. Significant correlations existed between the average number of leukocytes in the gingival exudate and the oral hygiene indices. The number of leukocytes increased significantly during the period of toothbrushing with the Fluoride dentifrice, whereas in the OHI no change was evident.

Dentifrices↗