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Biomedical subjects

W Haas

Publications and source records attributed to W Haas.

At least 145 records · Page 8Linked to original sources
PubMed1978

[The operative treatment of prolapse of the rectum (author's transl)].

Different kinds of mucosal prolapse at the rectum are differentiated. True and prolapse with protrusion of considerable portions of the rectum principally occur in later life. For younger patients several rather complicated operative procedures for the elimination of anal prolapse come into consideration, but usually they cannot be reasonably accepted by older patients. For this reason a simple method is recommended which carries little risk and yet promises satisfactory result--such as the insertion of a Thiersch ring. Whereas with this technique, if correctly carried out, improvement of the condition is almost certain to be expected, the longterm result over several years is limited, as a followup examination showed. Insertion of a Thiersch ring can, howeever, be repeated without difficulty. This procedure will retain its indication because of its simplicity.

Anesthesia, Local↗
PubMed1978

Investigations on the structure-activity relationships of verapamil.

An investigation was carried out towards a qualitative and quantitative structure-activity relationship of verapamil based on an analysis of the frequency-dependent negative inotropic action exerted in cat papillary muscles by various groups of verapamil derivatives. (1) Substituents of the benzene ring near the asymmetric carbon atom and the isopropyl group were found to be no essential substituents for the frequency-dependent negative inotropic action of verapamil but to have a strong influence on the potency of the drug. (2) Both the tertiary amino nitrogen and the two benzene rings are essential for the frequency-dependent negative inotropic action of verapamil (3) The molecular importance of the N-methyl group is probably based on steric effects. (4) Investigations of the verapamil derivative H 1 revealed that a quaternization of the drug is followed by a total loss of effectiveness. (5) No significant correlation of the biological activity of verapamil derivatives with the partition coefficient P has been obtained. (6) Hansch analysis with verapamil derivatives of group A (= different substitution of the benzene ring near C) shows that the variance of biological activity can be optimally correlated to a combination of the Hammett constant and the molar volume. Hansch analysis of group B (= exchange of isopropyl group) led to the conclusion that hydrophobic effects are responsible for the influence of the isopropyl substituent.

Animals↗
PubMed1978

Major histocompatibility complex-linked immune-responsiveness is acquired by lymphocytes of low-responder mice differentiating in thymus of high-responder mice.

Female murine T cells can respond to the Y antigen of male cells by generating cytotoxic T-killer lymphocytes. Responsiveness is linked to several H-2 genes. Two types of low responders can be distinguished: the B10.A(5R) (H-2i5) strain, a low responder because it lacks Y-specific precursor T cells able to differentiate into cytotoxic T-killer cells; and the CBA/J (H-2k) strain, a low responder because it lacks Y-specific T-helper cells able to support differentiation of T-killer cell precursors. B10.A(5R) stem cells differentiating in an x-irradiated (CBA/J X C57BL/6) (H-2k X H-2b)F1 host respond to Y antigen by generating T-killer cells whereas CBA/J stem cells do not. The results are consistent with the hypothesis that diversity of T-cell receptors is generated by somatic mutation of germ-line genes encoding specificity for self-H-2. A detailed account of this hypothesis is presented.

Animals↗
PubMed1977

H-2 gene complementation in cytotoxic T cell responses of female against male cells.

H-2 gene-dependent nonresponsiveness and responsiveness to H-2-matched male cells can be observed in cytotoxic assays in several mouse strains. H-2 genes of several low responder strains can complement each other in cis or trans position to produce high responders. One of the H-2 gene products functions at the level of antigen-presenting cells (stimulators, targets), the other must be expressed in the responding T cell population.

Animals↗
PubMed1977

[Value of ophthalmodynamography and ophthalmodynamometry in acute cerebrovascular processes].

Methods of examination are briefly described and findings are then reported for cerebral vascular processes. The results have been assessed in comparison with the angiographic picture. The authors conclude that both ophthalmodynamography and ophthalmodynamometry can be used to record haemodynamic changes resulting from stenosing vascular processes in the extra-cranial cerebral vascular area. The two methods are non-operative and involve little stress on the patient during examination so that they may be used for preliminary diagnostic purposes.

Acute Disease↗
PubMed1977

[Localized 4-sec and rhythm in the EEG].

The author, after presenting diagnostic criteria and interpretations of the 4-sec. rhythm in the brain potential record, describes a case where this symptom is localized in the right occipital region. He also points out that further elucidation should be possible by a differential establishment of indications.

Action Potentials↗
PubMed1976

[The attachment response of the cercaria of Schistosoma mansoni. Influence of natural substrates and temperature (author's transl)].

The behaviour of the cercaria, following contact with different animal and human substrates during swimming, has been studied. Four patterns of behavior related to the intensity of stimulation can be distinguished: 1. backward reaction, 2. stopping, 3. forward reaction, 4. attachment (Figs. 2 and 3). Mechanical stimulation of the cercaria by touching or water turbulence, prior to contact with the substrate has an insignificant effect on attachment. Both attachment and the first step in penetration (crawling over the substrate) are stimulated by a rise in temperature (Figs. 4 and 5) and the chemical properties of the substrate. However, the steps in penetration may possibly be stimulated by chemical components and perceived by receptors different from those involved in attachment.

Animals↗
PubMed1976

On the evocability of a positive oestrogen feedback action on LH secretion in transsexual men and women.

In transsexual men with homosexual behaviour and intact testicular function, as well as in homosexual men with normal gender identity, following a negative oestrogen feedback effect a delayed positive oestrogen feedback action on LH secretion was evoked. By contrast, in transsexual men with hypo- or asexuality and intact testes or hypergonadotrophic hypo- or agonadism, as well as in heterosexual men with normal gender identity, a negative oestrogen feedback effect was not followed by a positive feedback action on LH release. In transsexual women with homosexual behaviour and oligo- and/or hypomenorrhoea, only a weak or at best moderate positive oestrogen feedback action on LH release was evocable, similarly as in castrated and oestrogen-primed heterosexual men. By contrast, in a transsexual woman with bisexual behaviour and eumenorrhoea, a strong positive oestrogen feedback action on LH secretion was evocable, as well as in heterosexual women with normal gender identity.

Brain↗