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M Wälti

Publications and source records attributed to M Wälti.

32 records · Page 2Linked to original sources
PubMed1982

Effect of storage of penicillin-G solutions on sensitisation to penicillin-G after intravenous administration.

Intravenous administration of a total dose of more than 200 million IU of penicillin-G led to sensitisation of lymphocytes and formation of specific anti-penicilloyl antibodies of the IgG class. These effects were prevented when the penicillin solution used was freshly prepared and given as a bolus rather than as a slow infusion. The causative antigens seem to be related not to penicilloylated high molecular weight impurities in the penicillin preparations, but to the degradation and/or transformation products of penicillin-G that form when the drug is in solution even if only for a few hours, and not only at room temperature but also at 4 degrees C. Thus penicillin solutions should be freshly prepared and administered from vials containing less than 10 million IU so that bolus doses can be given.

Adult↗
PubMed1982

Development of a serum-free defined culture medium for lymphoblast transformation tests of mouse spleen and thymus cells.

By analysis of thymidine uptake during the first 4 h of incubation and by examining the responsiveness of unfractionated mouse spleen cells upon mitogenic or allogeneic stimulation, some serum factors of major importance for in vitro cultivation of lymphocytes have been examined. Albumin and l-alanine are essential for the maximal preservation of the in vivo-initiated lymphocyte activity during the first hours of incubation in vitro. Transferrin plays a major role in the lymphocyte proliferation, induced by mitogens in vitro, and, finally, zinc and selenium exert a clear enhancing effect on the response to an allogeneic stimulation. The AATSZ medium (RPMI 1640 enriched with l-alanine, albumin, transferrin, zinc chloride, and sodium selenite) enables a proliferation of the same magnitude as or higher than FCS medium. The kinetics are the same, and the cell viability is comparable, but standardization is much simpler with AATSZ. This is primarily because FCS binds some mitogens and contains inhibitors. Consequently, the standardization of such a culture system is dependent on variations from serum batch to serum batch. On the other hand, the current composition of the AATSZ medium promotes the sticking capacity of T lymphocytes and does not support growth of all lymphoid cell lines. Consequently, this defined medium, although not yet suitable as optimal medium for all lymphocyte functions, can advantageously be used for short-term studies of most murine lymphocyte functional and cooperation studies in vitro.

Alanine↗
PubMed1981

Neutropenia after penicillins: toxic or immune-mediated?

Eight patients treated with a total of 220-550 million U penicillin-G developed neutropenia. These cases have been compared with eight patients receiving a similar dose of pencillin-G with no adverse reactions and with eight untreated subjects. All penicillin-treated patients showed raised levels of anti-IgG antibodies and lymphocyte culture stimulation indices. These values were highest in the neutropenia group. Both of the two tests significantly discriminated the three groups. Antineutrophil antibodies could be detected in four of seven neutropenic patients with a staphylococcal-slide-assay while indirect immunofluorescence and microcytotoxicity tests failed to reveal these antibodies. The literature dealing with neutropenias induced by penicillin-G and its congeners is reviewed. We conclude that (1) penicillin-G in doses exceeding a total of 200 million U frequently induces neutropenia, (2) an immune-mediated pathogenesis a highly probable, (3) neutropenia after penicillins is different from two hither-to accepted types of this side effect, (4) sufficiently high amounts of penicillin-G intravenously always induce sensitization against this drug.

Adolescent↗
PubMed1979

Hydroxy analogues of oxytocin and of lysine-vasopressin.

1 Synthetic analogues of oxytocin and of lysine-vasopressin with an hydroxyl group in either the L ro D configuration replacing the primary amino group have been tested for biological activity.2 [1-(L-2-Hydroxy-3-mercaptopropanoic acid)] oxytocin ([L-Hmp(1)]oxytocin) was 1.5 to 2 times more potent than oxytocin on the rat uterus in situ, the rat mammary strip and the rat mammary gland in situ and 3 times more potent on the rat isolated uterus.3 The pressor activity of [1-(L-2-hydroxy-3-mercaptopropanoic acid)-8-lysine]vasopressin ([L-Hmp(1), Lys(8)] vasopressin) was 2.2 and the antidiuretic activity 2.1 times that of lysine-vasopressin.4 The [D-Hmp(1)] analogues of oxytocin and vasopressin were much less potent than the [L-Hmp(1)] analogues.5 The responses to oxytocin and its hydroxy analogues in vivo were qualitatively indistinguishable but the pressor and antidiuretic responses to the hydroxy analogues of lysine-vasopressin were prolonged compared with those to the parent hormone.6 The hydroxy analogues of oxytocin and lysine-vasopressin were not inactivated by pregnancy plasma oxytocinase.7 The results are discussed in relation to the importance of the primary amino group for the biological activity and metabolism of the neurohypophysial hormones.

Animals↗
PubMed1975

Co-operative binding of oxytocin to bovine neurophysin II.

The interaction of oxytocin with bovine neurophysin II in 0.1 M-sodium phosphate, pH 5.8, was investigated by equilibrium-dialysis and sedimentation studies. Sigmoidality of the binding curve is attributed to isomerization, either hormone-induced or pre-existing, with preferential binding of oxytocin to one isomeric state. Results are consistent with a binding equation of the form r = (2P[S]+2PQ[S]2)/(1+2P[S]+PQ[S]2) and values of 0.7 X 10(5)M-1 and 1.3 X 10(5)M-1 for P and Q respectively. The significance of these two parameters in relation to current theories of allostery is also discussed.

Animals↗