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Biomedical subjects

W Pohle

Publications and source records attributed to W Pohle.

At least 55 records · Page 3Linked to original sources
PubMed1984

Identification of neurons of origin providing the dopaminergic innervation of the hippocampus.

It was proved if there is an innervation of the hippocampus by dopaminergic neurons of the ventral tegmental area. Methods of labeling neurons by intrahippocampal injections of retrograde tracers were combined with fluorescence histochemical investigations of the same cells. An innervation of the hippocampus by the dopaminergic cell groups "A-9" and "A-10" could not be verified whereas, in the sphere of the raphe nuclei besides serotoninergic cells retrogradely labeled neurons were found exhibiting a dopamine like aminergic fluorescence.

Animals↗
PubMed1983

Dopaminergic innervation of the hippocampus: evidence for midbrain raphe neurons as the site of origin.

The purpose of the study was to verify the site of origin of a postulated dopaminergic (DA) innervation of the hippocampus (HPC) in rats. The retrograde labeling of hippocampal afferents by Granular Blue (GB) was combined with the fluorescence histochemical identification of biogenic amines. Among the dopaminergic cell groups A8--A14 there was no one neuron labeled with GB. Some of the retrograde labeled neurons of the midbrain raphe nuclei (mainly B8-region) were identified as catecholaminergic, probably dopaminergic. It is concluded that mesencephalic dopaminergic fibers innervate the HPC, but that they arise from raphe nuclei rather than from the ventral tegmental area. In order to confirm these data neurophysiologically, hippocampal responses to electrical stimulation of midbrain raphe nuclei were recorded in freely moving Wistar rats. The intrahippocampal injection of the DA antagonist haloperidol through a chronic microcannula caused two types of changes in average evoked potentials: A significant decrease in the amplitude of an early, negative component (peak latency 8 ms). An increase in the amplitude of a second, positive component, which occurred only after a preceding inhibition of serotonine synthesis. The haloperidol sensitivity of the early component of hippocampal responses is interpreted as support of the morphological data about an ascending dopaminergic input from the median raphe nucleus to the hippocampus.

Afferent Pathways↗
PubMed1983

PAGE-autoradiography of fucose incorporation into rat hippocampal glycoproteins after acquisition of a brightness discrimination.

Male rats aged 8 weeks received intraventricular injections of 100 microCi (3.7 MBq) L-[1-3H] fucose each, 7 h after acquisition of a brightness discrimination task. Two, 8 and 24 h as well as 16, 29 and 60 days after injection of labelled fucose hippocampal tissue was prepared to obtain Tris-soluble, Triton-soluble and Triton-resistant fractions. Two and 8 h after application of [3H]fucose, the trained animals revealed an increased incorporation of fucose mainly into the Triton-soluble glycoproteins. However, it is considered that also material from the Tris-soluble fraction may be used as an additional precursor for Triton-soluble glycoproteins. Quantitative analysis of autoradiographic densitograms obtained after SDS-polyacrylamide gel electrophoresis showed the occurrence of a training-related increase in fucose incorporation predominantly into the slow-moving Triton-soluble glycoproteins. The latter exhibited a higher turnover rate than the faster-moving glycoproteins. For the longer incorporation times (days) after injection of labelled fucose, no differences were observed between trained animals and corresponding active and passive controls.

Animals↗
PubMed1982

Distribution of hippocampal glycoproteins as demonstrated in rats by lectin binding and autoradiography after intraventricular injections of labelled fucose, N-acetyl-glucosamine and mannose.

The present study demonstrates distinct distribution patterns of glycoproteins in rat hippocampus, with respect to synthesis from precursors (autoradiography) and endogenous contents (lectin binding). The autoradiographic analysis performed 1, 2, 8 and 24 h after intraventricular injections of tritium-labelled L-fucose. N-acetyl-D-glucosamine and D-mannose revealed that up to 2 h after application of any of the three precursors, radioactivity occurred in the pyramidal and granular cell layers. Afterwards, however, rapid migration of label proceeded from the cell bodies into the neuropil after application of fucose and acetylglucosamine, while after injection of mannose a considerable amount of radioactivity stayed in the cell body layers, even 24 h after administration of labelled precursor. These findings were consistent with the histochemical visualization of glycoprotein constituents by fluorescent wheat germ lectin (preferentially binding to glucosaminyl residues) and concanavalin A-horseradish peroxidase (preferentially binding to mannosyl residues). These showed a heavy staining predominantly in neuropil and somata, respectively, with concanavalin A-binding giving more distinct patterns than the application of labelled mannose. The usefulness of the three glycoprotein precursors as correlates with functional behavioural changes in discussed.

Acetylglucosamine↗
PubMed1982

[Autoradiographic detection of 3H-labelled glycoproteins in "light" and "dark" neurons of gray matter of the rat brain following intraventricular application of 3H-fucose. Preliminary report].

The simultaneous demonstration of 3H-radioactivity and "light" and "dark" neurons by histological staining revealed that the occurrence of "light" and "dark" neurons are morphological correlates of different activity stages of cell metabolism. In this connection it became evident that "light" nerve cells incorporated significantly greater amounts of fucose and therefore should be regarded as metabolically more active. We also present evidence that "dark" neurons are not artificial products caused by postmortem trauma to the brain inadequately fixed (as pointed out by Cammermeyer).

Animals↗
PubMed1981

[Scintigraphic diagnosis of sport injuries: multiple fractures of ribs by golf-players (author's transl)].

Three untrained golf-players suffered from pain in the dorsal region of the left thorax after some training hours. Three to four weeks after the pains had begun serial fractures of ribs were diagnosed by 99mTc-MDP bone-scan-examinations. All fractures were localized near the costal angulus (paravertebral) of these ribs. The fractures are causal by manual tensions. The difficulties in timing the bone-scan and in identifying the morphologic substrate are demonstrated. It is recommended, that golf-players suffering from thoracic pain ought to be examined by bone scan.

Adult↗
PubMed1980

A new conformation-specific infrared band of A-DNA in films.

A band at 1185 cm-1 occurs in the infrared spectra of nucleic acids in their A-type conformation which has been reproduced in the literature, too. The absorbance of this band is proportional to the fraction of the A form of DNA samples containing a mixture of different forms. The 1185 cm-1 band has been assigned tentatively to a vibration of the sugar-phosphate backbone with a fairly high contribution from the sugar moiety. Drastic dehydration of the DNA films is accompanied by a continuous intensity decrease of the 1185 cm-1 band indicating a collapse of the A form.

Animals↗
PubMed1980

On the interaction of caffeine with nucleic acids. IV. Studies of the caffeine-DNA interaction by infrared and ultraviolet linear dichroism, proton and deuteron nuclear magnetic resonance.

The DNA-caffeine interaction at high concentration of caffeine (Cf) leads to an arrangement of Cf molecules outside of the DNA double helix with an orientation parallel to the bases both in the A and B form as demonstrated by infrared linear dichroism. Addition of DNA broadens the 1H NMR lines of Cf in aqueous solution indicating a specific binding. Intercalation is not the predominant mechanism, the deuterium relaxation time T1 = (38 +/- 7) ms and the estimated reorientation correlation time tau cb = 0.17 ns of caffeine-8[2H] in the Cf-DNA complex suggest an outside stacking of the ligand. According to the results a model on the DNA-Cf complex at high Cf concentration (binding process II) is suggested including the caffeine-induced reorientation of the hydration shell of DNA.

Caffeine↗
PubMed1980

Intraventricularly applied D-galactosamine inhibits the incorporation of [(3)H]-fucose into rat brain glycoproteins.

In the rat, intraventricularly applied D-galactosamine (GalN) (10 or 20 mumoles) inhibited [(3)H]-fucose incoporation into hippocampal and subcortical glycoproteins by appr. 50% of the controls. The inhibitory effect occurred within 40 min after GalN administration and did not reach normal values even 16 h upon GalN injection. During the first hours upon GalN administration the inhibition of fucose incorporation involved predominanatly water-soluble and Triton-soluble glycoproteins, whereas the Triton-resistant fraction showed a delayed suppression. The results suggest that GalN suppresses the formaton of membrane glycoproteins (because only 15% of fucose radioactivity remained in water-soluble fraction) which are believed to play an essential role in formation of long-term memory. Under these aspects, the amnesic effect of GalN on the retention of a brightness discrimination and the abolishment by uridine treatment, as observed in our laboratory, may be interpreted as a further support to the particular role of glycoproteins in the consolidation of a memory trace.

Animals↗
PubMed1980

Visualization of rat brain glycoproteins in polyacrylamide gels by means of concanavalin A-peroxidase.

A reliable method for visualization of mannose-containing glycoproteins in electrophoretically (SDS-PAGE) separated Tris-soluble, Triton-soluble and Triton-resistant fractions obtained from rat hippocampus, brain region supposed to play an essential role in learning and memory processes, was elaborated. The method is based on the Concanavalin A-horseradish peroxidase reaction applied successfully for the purpose of light and electron microscopic visualization of cellular carbohydrate components.

Animals↗
PubMed1979

Treatment of arteriovenous angiomas of the kidney: surgical intervention and intra-arterial embolization.

Angiomas of the kidney are benign vascular dysplasias, which usually can be identified angiographically. If there are no clinical symptoms treatment is not necessary. In cases of hematuria and/or hypertension either intra-arterial superselective embolization seems to cause less functional loss of the renal parenchyma, whereas excision often leads to heminephrectomy or even total nephrectomy. Even if the angioma is initially not completely embolized followup study to 2 years has shown complete occlusion of the angioma, either owing to inflammatory reactions or redistribution of blood flow and diminished blood pressure. Two cases of renal angiomas are presented. Treatment consisted of intra-arterial superselective embolization in 1 case and surgical clipping of the supplying arterial branch in the other.

Adult↗
PubMed1979

[Arterio-venous angioma of the kidney: embolisation and two year follow-up (author's transl)].

Successful embolisation of an arteriovenous angioma of the kidney with gel foam suspension is described, with a two year follow-up. Embolisation cured hypertension, which had otherwise resisted treatment, and stopped haematuria. The need for careful follow-up is stressed with long-term observations using both angiography and scintigraphy of the affected kidney. The intra-arterial embolisation with gel foam resulted in a redistribution of blood-flow which led to complete success of treatment even thought the vascular malformation had not been totally obliterated.

Adult↗
PubMed1979

Complexing of reduced technetium and tin (II) by chelating phosphate compounds. I. Chemical state of technetium.

Complexing of reduced 99mTc, 99Tc and of 113Sn(II) by pyrophosphate was studied, using the in vivo distribution in the rat as an indicator for complex formation. 99mTc-pyrophosphate was only formed at very low technetium concentrations, otherwise colloid formation occurred. Reduced 99mTc in trace amounts and 113Sn(II) complexed equimolarly with pyrophosphate were concentrated in bone and excreted in urine in comparable amounts. The in vivo distribution of 32P-orthophosphate and -pyrophosphate was characterized by a considerable uptake in the liver and a poor urinary excretion. The distribution patterns of 32P-pyrophosphate, complexed equimolarly with tin(II), remained unchanged. Despite these findings it is concluded that real chelates are formed, since non-complexed reduced 99mTc was not concentrated in bone. Two variants of reduced technetium could be discerned: a 99mTc-kidney agent and a 99mTc protein-bound agent. Some evidence was found that reduced technetium may change its oxidation state, but it seems much more likely that both agents are technetium(IV) compounds. It is suggested that the kidney agent is hydrated technetium dioxide whereas the protein-bound agent is a charged technetium(IV) compound. Only hydrated technetium dioxide is obviously complexed by chelating phosphate compounds.

Animals↗