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H Rennert

Publications and source records attributed to H Rennert.

At least 37 records · Page 2Linked to original sources
PubMed1989

Mechanism of the luteolytic action of prostaglandin F-2 alpha in the rat.

PGF-2 alpha suppresses the LH-induced accumulation of cyclic AMP in young and mature corpora lutea (CL) of pseudopregnant rats, with mature CL being more sensitive. Calcium ions, and later phospholipase C activation, are believed to mediate this effect. In isolated CL of 2 and 10 days of age, depletion of extracellular calcium, or addition of calmodulin inhibitors or of 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxy-benzoate (TMB-8), did not prevent the suppressive effect of PGF-2 alpha. Phorbol 12-myristate 13-acetate augmented, rather than inhibited, the LH-induced cAMP accumulation in young and mature CL. Polyphosphoinositide turnover was stimulated by PGF-2 alpha in young, but not in mature CL. The suppression by PGF-2 alpha of luteal cAMP is therefore apparently not mediated by phospholipase C activation but two phosphodiesterase inhibitors, 3-isobutyl-1-methylxanthine and Ro-20-1724, abolished the inhibitory effect of PGF-2 alpha.

1-Methyl-3-isobutylxanthine↗
PubMed1989

[Paraneoplastic polyneuropathies].

As paraneoplastic polyneuropathy is still too rarely diagnosed, thus precluding the possibility of early recognition and treatment of the malignant tumor, usually a bronchogenic carcinoma, the paper sets out symptoms, epidemiology, and differential diagnosis of the condition, whose therapy and prognosis being uncertain.

Humans↗
PubMed1989

Unnecessary hospitalization days: rates in two general hospitals in Israel.

The efficient use of hospital resources is an important issue. In order for the hospital management to identify definite areas where and why this use is inefficient, the Appropriateness Evaluation Protocol is used. The rate of unnecessary hospitalization days was thus studied during 1984 in two government general hospitals in Israel. Two simultaneous studies, cross-sectional and longitudinal, were conducted by the same team in the general medicine, surgery and gynecology wards. Unnecessary hospitalizations were found in both hospitals. The rate was particularly high in the surgery departments of the university hospital where there were 2.5-3 times more unnecessary days than in the community hospital. The major reasons for these unnecessary days in the university hospital were internal (problems concerning the use of diagnostic facilities, operating rooms and consultants), whereas in the community hospital they related mainly to discharge planning. The study identified definite areas in which hospital authorities could possibly take action to reduce the wastage.

Adolescent↗
PubMed1987

Calmodulin inhibitors and 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate do not prevent the inhibitory effect of prostaglandin F2 alpha on cyclic AMP production in isolated rat corpora lutea.

In the rat corpus luteum, prostaglandin F2 alpha (PGF2 alpha) rapidly inhibits LH-induced cyclic AMP (cAMP) production when given in vivo or to isolated corpora lutea, but not to broken-cell preparations. The suggestion that increased cytosolic calcium concentration mediates PGF2 alpha action was investigated in corpora lutea of pseudopregnancy induced in immature rats by administration of pregnant mare serum gonadotrophin (15 i.u.). Isolated 10-day-old corpora lutea were incubated for 90 min with LH (5 micrograms/ml), PGF2 alpha (10 mumol/l) and other additions, and cAMP concentration in the tissue was estimated. The putative inhibitor of intracellular calcium release or action, 8-(n,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate (TMB-8; 30 or 150 mumol/l), did not abolish the effect of PGF2 alpha. Similarly ineffective was the combination of TMB-8 (150 mumol/l) and calcium-depleted medium (free ionized calcium concentration, 30 nmol/l). Calmodulin inhibitors of three different chemical structures were then tested. The phenothiazine trifluoperazine, at 300 as well as 30 mumol/l, did not interfere with the inhibitory effect of PGF2 alpha on cAMP, while suppressing (at 300 mumol/l) progesterone secretion in LH-treated tissue. Furthermore, inhibition by PGF2 alpha was not impaired by pimozide, a diphenylbutylpiperidine (25 and 50 mumol/l) nor by N-(6-aminohexyl)-5-chloro-1-naphthalene sulphonamide (W-7; 15 and 45 mumol/l). In the presence of LH alone, W-7 (45 mumol/l) inhibited and TMB-8 (30 mumol/l augmented cAMP accumulation, indicating that the luteal tissue was effectively exposed to these compounds. Thus, drugs known to inhibit calcium- and calmodulin-dependent processes in a variety of tissues did not abolish the inhibitory action of PGF2 alpha on luteal cAMP production.

Animals↗
PubMed1986

Inhibition by vanadate of cyclic AMP production in rat corpora lutea incubated in vitro.

Vanadate, a normal constituent of cells, has been reported to affect a variety of enzymes involved in phosphate transfer; the findings regarding adenylate cycle vary with the tissue and experimental system. In the corpus luteum, cyclic AMP (cAMP) stimulates steroidogenesis; and prostaglandin F2 alpha, which induces luteal regression, inhibits luteinizing hormone (LH)-induced cAMP accumulation. We examined the influence of orthovanadate on cAMP concentration in isolated corpora lutea from pseudopregnant rats. With 2 mM vanadate, basal cAMP level was unaffected, but LH-induced cAMP accumulation was inhibited by 45-68%. Lower doses of vanadate (0.2-1 mM) were almost as effective. When added simultaneously with LH, vanadate was inhibitory within 25 min, but no inhibition occurred when vanadate was added for 30 min to tissue pretreated with LH for 60 min. The decrease in cAMP accumulation was observed also when corpora lutea were exposed to vanadate in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (0.5 mM), indicating that vanadate inhibits cAMP synthesis. Vanadate may increase cytosolic calcium by inhibiting ion pumps in cell membranes. Thus, we examined the effect of vanadate in corpora lutea incubated in calcium-depleted medium and found that vanadate still inhibited cAMP formation. Vanadyl sulfate (0.4 and 2 mM) reduced the LH-induced cAMP accumulation as effectively as vanadate. Thus, the use of vanadate as a tool for exploring physiological regulators of luteal adenylate cyclase should be considered.

1-Methyl-3-isobutylxanthine↗
PubMed1984

[Psychological and sexual effects of hormonal contraceptives--results of a survey].

Subject of our examination are emotional-affective, vegetative and psycho-sexual disturbances which are possibly caused by oral contraceptives. 511 women, taking different oral contraceptives, were questioned. For that purpose we used a schedule of sociological dates, attitudes and complaints devised by ourself and connected with a part of Böttcher's Introversion-Neurotizism-Rigidity-Questionnaire. Neurotic and introverted persons are tending to suppose a connection between the "Pill" and certain inconvenient sensations as affective disturbances, diminished concentration, dyssomnia and an avoidance behavior in sexuality. But the results of investigation gave also evidence for a distinct increase of sexual unaffectedness without disadvantageous uninhibition. A classification of the disturbances relative to the particular drugs did not reveal any differences within our cases. The sample "Gravistat" had significantly raised scores of neurotizism and here can also be observed an increase of inconvenient psychical disturbances. We recommend to give better information on the mode of action of the respective contraceptives. In cases of neurotic attitude a psychotherapeutical consultation between doctor and patient may diminish psychosexual disturbances as symptoms of the application of oral contraceptives.

Adult↗
PubMed1982

[Notes on the model "universal genesis of psychoses"--aspects of an unconventional interpretation of mental diseases (author's transl)].

The article describes a temporarily closed model of a uniform interpretation of all endogenous psychosyndromes (universal genesis of psychoses) which, however, is capable of extension and modification. This concept, which was developed in 1964, does not postulate a "unitary psychosis" in the narrow sense of the term. It is based mainly on results obtained in traditional psychiatry and combines individual aspects and opinions which are used by other psychiatrists also who share these opinions although mostly they do not employ them as general principles. To substantiate the author's own position, several old and new problems of the doctrine of psychoses are illuminated from a uniform point of view. In this synopsis biologically relevant aspects are emphasized, especially those of the common pathogenetic fundamentals, the common phases of the disease, as well as the agreements in recording of the syndromes. The final section of the study provides a condensed survey of the essential factors and consequences of the concept, supplying details to supplement this brief review.

Atrophy↗
PubMed1982

[Correlative aspects between function and structure in hippocampal processes (Ammon's formation)].

In post-mortem material with pronounced primary epilepsy-independent pathomorphic findings of Ammon's formation, the correlation with symptomatic epilepsy and the typical psychic disturbance phenomena was studied. While a connection between the lesion and the epileptic disease could be confirmed with a certain probability, this remains problematic with respect to impairments of memory, orientation capacity, working-up of experiences and drive and reaction capacity. Although in all examined subjects clinical deficiency phenomena of one type or the other were present, additional lesions, especially of nuclear regions which are associated with AF and cortical structures will certainly also be responsible.

Adolescent↗
PubMed1977

[Etiology and classification of mental disorders from viewpoint of "Universal genesis of psychoses"].

The concept of a "Universal genesis of psychoses" has been worked on by the author for about 12 years. It is mostly biologically orientated and deals with the development, classification and therapy of psychotic syndromes in an unconventional manner. Prejudices which would only interfere with research have been avoided as far as possible, and new results e.g. of biochemistry have been included. A more purposeful treatment with psycho-pharmacological agents is aimed at. Special emphasis is laid on the negation of real demarcations between manic-depressive, cycloid and schizophrenic syndromes which are assumed to be caused by many factors, and on the fact that psychopathological basic symptoms are "fundamental conditions" principally characteristic of all psychotic syndromes in different constellations.

Brain↗