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Biomedical subjects

M Schlumpf

Publications and source records attributed to M Schlumpf.

At least 73 records · Page 4Linked to original sources
PubMed1983

Ontogeny of diurnal rhythms of central dopamine, serotonin and spirodecanone binding sites and of motor activity in the rat.

The binding of 3H-spiperone to its 3 high affinity sites (dopaminergic D2, serotonergic S2 and spirodecanone site) was determined in forebrain homogenates of 14,30 and 88-90 day old male rats at different times of the day. Diurnal variations were seen in the spirodecanone site from postnatal day 15, in the D2 and S2 sites at the age of 30 days. Each site showed a different diurnal rhythm, moreover, the rhythms of the D2 and S2 sites differed between immature and adult animals. Diurnal variations of motor activity were recorded at the age of 30 and 88-90 days. The two developmental stages differed with respect to the activity pattern of the dark phase. At both stages, the motor activity pattern was found to be a mirror image of the variation in D2 binding sites during the dark phase. Our data point to differences in the regulation of various neuroleptic binding sites in immature and adult animals. They further suggest a link between the dopaminergic D2 site and motor activity which is evident throughout ontogeny.

Aging↗
PubMed1983

Assessment of stenoses in coronary angioplasty. Inter- and intraobserver variability.

Three observers twice assessed coronary artery lesions of 10 patients in three oblique views using the films obtained before, immediately after, and six months after percutaneous transluminal coronary angioplasty. In order to improve accuracy of the interpretation, the stenoses were traced from the cine projector and the diameters measured with a calibrated magnifying glass. Interobserver and intraobserver variability of the commonly used method assessing only the projection showing the most severe stenosis was compared to that of a method assessing the mean of three projections. The interobserver coefficients of variation were 7.0% for using the one projection showing the most severe stenosis and 6.4% for using the mean of three projections (not significant). The intraobserver coefficient of variation was significantly reduced from 16.0 to 10.5% (P less than 0.0001) by using the mean of three projections. The assessment of three projections instead of one justifies the additional time needed by significantly increasing assessment reliability which is of great importance in evaluating and comparing anatomical results of percutaneous transluminal coronary angioplasty.

Angioplasty, Balloon↗
PubMed1983

Pre- and postnatal ontogeny and characterization of dopaminergic D2, serotonergic S2, and spirodecanone binding sites in rat forebrain.

The ontogeny of binding sites for [3H] spiperone was studied in time-pregnant rats. Binding of [3H]spiperone to fresh homogenates of pre- and postnatal rat forebrain was characterized by Scatchard analysis and competition experiments with a number of dopaminergic and serotonergic agonists and antagonists and additional substances. A convenient discrimination of three high-affinity sites, i.e., the dopaminergic D2, serotonergic S2, and spirodecanone (Sd) sites, was obtained with l-(-)sulpiride and cis-flupenthixol. The analgesic R5573 was found not to be specific for the Sd site but to interact with all three sites. The three binding sites became detectable in sequential order. S2 and D2 binding sites were first found at embryonic days 15.75 and 17.75, respectively. The Sd site did not appear before postnatal day 8. All three binding sites reached adult values at approximately postnatal day 30. During the prenatal period, the increase in the number of D2 binding sites paralleled the rise in forebrain dopamine concentrations. The kinetics of D2 and S2 sites were the same at embryonic day 19.75 and postnatal day 30. These observations provide evidence for the presence of the receptor substrate for actions of neuroleptics on dopaminergic and serotonergic systems during fetal life.

Aging↗
PubMed1983

Long-term exercise performance after percutaneous transluminal coronary angioplasty and coronary artery bypass grafting.

In our first 169 consecutive patients admitted to undergo percutaneous transluminal coronary angioplasty (PTCA) serial bicycle ergometric exercise sessions were scheduled to assess long-term-exercise performance. In 160 of these 169 patients (95%) an average of seven ergometric measurements were available during a mean follow-up period of 29 months (range 1 to 60 months). Two groups were formed. One consisted of 132 patients in whom PTCA was successful and the other consisted of 28 patients with failure of PTCA who subsequently underwent coronary artery bypass grafting (CABG) either on an emergency basis (12 patients) or as an elective procedure (16 patients). Exercise performance was expressed as work capacity in watts according to the highest completed exercise stage. In the successful PTCA group the actual work capacities increased from 74 +/- 42 W (mean +/- SD) before PTCA to 122 +/- 47 W at the most recent follow-up examination. In patients who underwent emergency or elective CABG the respective figures were 73 +/- 34 or 65 +/- 37 W before surgery and 120 +/- 41 or 119 +/- 41 W at the most recent follow-up examination (p less than .005 for all preprocedure to postprocedure comparisons). Successful PTCA and CABG after failed PTCA improve work capacity significantly. Comparison of our results with those of surgical studies indicates that a failed attempt at PTCA before CABG does not compromise the functional outcome of the operation, regardless whether it is done on an emergency or on an elective basis.

Angioplasty, Balloon↗
PubMed1982

Stimulation of nigrostriatal dopamine neurones by nicotine.

In rats anaesthetized with urethane, firing of neurones of the substantia nigra zona compacta was accelerated after subcutaneous or iontophoretic administration of nicotine or after iontophoretic application of acetylcholine. The excitation was prevented by iontophoretic application of dihydro-beta-erythroidine, but not by atropine. The units were identified by antidromic stimulation as neurones of the nigrostriatal system; their activity was depressed by iontophoretically applied dopamine (DA). Under the same conditions of anaesthesia, a subcutaneous injection of nicotine produced an increase in DA turnover and in homovanillic acid levels in the striatum. The effect of nicotine on striatal DA turnover was comparable to that of electrical stimulation of the nigrostriatal pathway at the average frequency seen in the firing of zona compacta neurones after systemic administration of nicotine. These observations corroborate the idea that nicotine exerts an excitatory action at the level of nigral DA nerve cells. Observations made after electrical stimulation or haloperidol under urethane anaesthesia and after nicotine in unanaesthetized rats suggest that the relatively modest effect of nicotine on striatal DA turnover is due mainly to the short duration of drug action rather than to effects of the anaesthetic on DA metabolism.

Animals↗
PubMed1980

Innervation of embryonic rat cerebral cortex by catecholamine-containing fibers.

Catecholamine-containing neuronal processes penetrate to the outer superficial layers of the developing neocortex via the lateral neocortex anlage by embryonic day (ED) 16, only 48 hours after the final cell division of the catecholamine neurons in the mesencephalon and pons-medulla. Sagittal sections were taken from a series of perfused embryos at precise time-intervals after insemination. The corpus striatum receives a large catecholamine input and serves as a reference for tracing the very fine varicose processes that course through the caudate nucleus to innervate the more rostral structures of the developing neocortex cerebri. The input fibers to the neocortex arrive via three to four small fiber bundles, entering chiefly at the ventro-rostral aspect. The bundles than bifurcate into the deep and superficial layers of the cortex. Between ED16 to ED21 the innervation progresses in ventral to dorsal and rostral to caudal directions. Embryonically, fluorescent fibers are observed in the outermost superficial layer and in the intermediate zone, below the cortical plate; only rarely are they seen crossing the cortical plate. The demonstration of monoaminergic neuronal fibers reaching neocortical structures by ED16 adds further weight to the speculation that they may play a role in induction and differentiation, and suggests that post-natal experimental manipulations using ascending-bundle lesions will have been performed at least five days after the arrival of catecholamine fibers at their cortical destinations.

Animals↗
PubMed1980

[Percutaneous transluminal dilation by catheter of coronary - artery stenosis (author's transl)].

Since September 1977 until July 1979, 82 patients with various coronary lesions have undergone percutaneous transluminal coronary angioplasty (PTCA). By this technic, a catheter system is introduced through a systemic artery under local anesthesia to dilate a stenotic artery by controlled inflation. In 60 patients (73%) anatomical and hemodynamic success could be noted, which led to improvement in clinical parameters e.g. reduction of coronary narrowing of the transluminal diameter from a mean of 82 +/- 11% to 34 +/- 16% (p less than 0.001) and reduction of trans-stenotic coronary gradient from 56 +/- 15 to 19 +/- 12 mmHg (p less than 0.001). Nine patients, three of whom had signs of transmural myocardial infarction on the ECG had undergone emergency surgery for a coronary by-pass, this been due to the deterioration of clinical condition after the attempt to carry out coronary angioplasty. 42 out of 60 treated patients had at least one late control. 33 showed an improvement in cardiac efficiency campared with the pre-dilatation period. Patients with uncalcified single-vessel stenosis, less than 1 cm in length and a short history of pain appear to be most suitable for the procedure. More cases and follow-up datas are necessary to evaluate the efficiency of this new technic as compared with current medical and surgical treatments of ischemic heart disease.

Adult↗
PubMed1979

Catecholamines in the yolk sac epithelium of the rat.

Catecholamines were found histochemically in the visceral yolk sac of the rat from embryonic day (ED) 10, i.e. before the amines become detectable in peripheral or central neurons of the fetus. Formaldehyde-induced fluorescence was confined to the apical part of the yolk sac epithelial cells. The specificity of histofluorescence has been confirmed by borohydride reduction, microspectrofluorimetry revealing an emission peak at 480 nm and administration of reserpine. The catecholamines present were identified by mass fragmentography using N,O-trifluoroacetyl derivatives. At ED 13 both dopamine and norepinephrine were present, while only dopamine was detected at ED 18 1/2. Maternal circulation or the epithelial cells themselves appear as possible sources of these catecholamines. The occurrence of amines in the yolk sac epithelium may reflect an intracellular role of these compounds, a barrier function of the epithelium or a step in a transport to the fetus where the amines might assume regulatory functions.

Animals↗
PubMed1977

Explant cultures of catecholamine-containing neurons from rat brain: biochemical, histofluorescence, and electron microscopic studies.

Norepinephrine (NE)-producing cells of the nucleus locus ceruleus and dopamine (DA)-producing cells of the substantia nigra were dissected microscopically from embryonic rat brain, explanted, and maintained in culture for up to 5 weeks. The cultured neurons of both brain regions showed normal maturation of axons and dendrites and formed ultrastructurally defined synaptic contacts. Fluorescence microscopy of cultured neurons from both brain regions showed typical in situ cytological features: long axonal processes with multiple varicosities for locus ceruleus cultures, and smooth, wispy nonvaricose processes in the substantia nigra cultures. All cultures processed for fluorescence microscopy contained specific catecholamine-fluorescent cells. By radioenzyme assay for catecholamines, more than half of the locus ceruleus cultures contained measurable (>10 pg) quantities of NE and DA, but, unlike results on intact brains, DA content exceeded NE content. Cultures of substantia nigra neurons retained no NE and very little DA. Media from substantia nigra and locus ceruleus cultures contained substantial quantities of DA. Addition of reserpine (10 muM) to the medium depleted locus ceruleus neurons of both amines. The long survival time in culture of locus ceruleus cells, the normal appearance of fluorescent cell bodies and processes, the apparent development of morphologically specialized interneuronal connections, and the ability to synthesize and store NE make these cultures ideally suited for neurophysiological recording as well as morphological, biochemical, and pharmacological experiments.

Animals↗