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Biomedical subjects

B Muller

Publications and source records attributed to B Muller.

At least 73 records · Page 4Linked to original sources
PubMed1984

Distribution of neurones containing DOPA decarboxylase and dopamine-beta-hydroxylase in some sympathetic ganglia of the dog: a quantitative study.

Using a technique by which binding sites for two antibodies can be visualized in single tissue sections, we have studied the distribution of neurones containing DOPA decarboxylase-like and dopamine beta-hydroxylase-like immunoreactivity in ganglia of dog sympathetic chain. Three types of neurones could be distinguished: those that contained both enzymes, and were presumably noradrenergic; those that contained neither enzyme, and were presumably not catecholaminergic; and a group that contained DOPA decarboxylase but lacked dopamine beta-hydroxylase. The numbers of cells of each type were counted in serially-sectioned ganglia from regions of the sympathetic chain thought to contain dopaminergic neurones (T12-L1 and L7-S2). The percentages of total cell numbers contributed by the DOPA decarboxylase-positive, dopamine beta-hydroxylase-negative cells in these regions were similar to the estimates of dopaminergic neurone numbers that can be made from previously obtained biochemical data. Our results are consistent with the presence of dopaminergic neurons in regions of the paravertebral chain supplying the kidney and the distal hindlimb.

Animals↗
PubMed1984

Characterization of chromaffin-like cells in the canine sympathetic chain by enzyme immunohistochemistry and quantitation of their distribution.

Some of the paravertebral sympathetic ganglia of the dog contain relatively large amounts of dopamine, which we have suggested previously is localized in dopaminergic neurones. However, the possibility exists that intraganglionic chromaffin-like cells may also be a source of dopamine. In order to resolve this question, we have examined the distribution of chromaffin-like cells in dog paravertebral ganglia (T7-S2) using formaldehyde-induced fluorescence of catecholamines and immunohistochemical localization of dopa decarboxylase, dopamine beta-hydroxylase and phenylethanolamine N-methyltransferase. The results have been compared with levels of the different endogenous catecholamines in equivalent ganglia. Clusters of between 20 and several thousand chromaffin-like cells were randomly present in ganglia at all levels of the chain, and were most common in the more caudal segments (L4 or below); but many ganglia contained no cells. About 24,000 chromaffin-like cells were found in 18 ganglia from six animals which were stained for dopa decarboxylase and dopamine beta-hydroxylase. In 16 of these ganglia, all of the 17,000 cells present contained both enzymes, indicating that they could synthesize noradrenaline. In the remaining two ganglia, 500 out of 7000 cells contained dopa decarboxylase, and therefore were capable of synthesizing dopamine, but appeared to lack the dopamine beta-hydroxylase necessary to convert this to noradrenaline. Five ganglia from three other dogs were stained for dopamine beta-hydroxylase and phenylethanolamine N-methyltransferase. A further 2600 cells were found in these ganglia and both enzymes were present in all of the cells, indicating that they could all synthesize adrenaline. Biochemical estimates of the various catecholamines showed that ganglia containing appreciable amounts of adrenaline had similar distributions to those containing chromaffin-like cells in the same animals. High concentrations of adrenaline were often correlated with high concentrations of noradrenaline but were not correlated with high concentrations of dopamine. It is concluded that paravertebral chromaffin-like cells in the dog store adrenaline, and also perhaps noradrenaline, but not dopamine. The high concentrations of dopamine found in certain ganglia cannot therefore be attributed to the presence of these cells. The erratic distribution of chromaffin-like cells suggests that they are unlikely to fulfil any general role in modulation of ganglionic transmission.

Animals↗
PubMed1977

Identifying and treating the drug-misusing patient.

The drug misusers whom physicians encounter in private practice are not the stereotypes. Treatment of drug problems is possible on an outpatient basis if physicians are willing to extend their normal role. Overcoming negative feelings toward patients who misuse drugs, employing some basic counseling skills and being aware of the relatively uncomplicated medical procedures involved in therapy can enable the physician to treat certain types of drug misuse in his own office.

Amphetamines↗
PubMed1976

Synthesis and characterization of blood compatible surfaces. Part I. Dynamic tube test applied to heparinized surfaces.

A 3 yr study has shown that this test procedure can monitor subtle differences in surface chemistry with a high degree of reproducibility. Based on the present studies, the test appears to be a valid screening tool for examining materials in a dynamic flow situation without the need for animal sacrifice often associated with blood testing. Also, due to the small amount of blood required, numerous samples can be run on the same animal which is extremely advantageous when comparing treatment methods. In addition, the simplicity of the test should make it easily adaptable to most blood testing laboratories.

Animals↗
PubMedDate not supplied

Effect of lipopolysaccharide treatment on neurogenic contraction and noradrenaline release in rat arteries.

In the present study, contractile responses and [3H]-noradrenaline overflow evoked by electrical field stimulation were assessed, respectively, in the small mesenteric artery and in tail artery removed from rats pre-treated with either saline or lipopolysaccharide (LPS). In small mesenteric arteries, LPS treatment did not significantly modify the contractile responses elicited by electrical stimulation, in the absence or in the presence of L-arginine. However, in arteries removed from rats treated with LPS, L-arginine addition produced relaxation of vessels pre-contracted with noradrenaline. The amplification of neurogenic contraction by the nitric oxide (NO) synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME) was similar in arteries removed from saline and LPS-infused rats. In mesenteric arteries, LPS treatment suppressed the potentiation of the neurogenic responses by the alpha2-adrenoceptor antagonist, yohimbine and by the inhibitor of neuronal uptake of noradrenaline, cocaine. In rat tail artery exposed to L-arginine, LPS treatment produced an increase in [3H]-noradrenaline overflow evoked by electrical stimulation. Altogether, these data suggest that an enhanced noradrenaline release from sympathetic nerves, probably resulting from inhibition of the modulatory effect of both prejunctional alpha2-adrenoceptors and neuronal uptake mechanism, may play a role in the preservation of neurogenic response after LPS treatment despite evidence of the induction of NO synthase.

Adrenergic alpha-Antagonists↗