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M Wenzel

Publications and source records attributed to M Wenzel.

At least 109 records · Page 6Linked to original sources
PubMed1987

Scanning electron microscopical observations on retina cells in culture.

In cell cultures of the retina from 10 days old chicken embryo photoreceptors, bipolar neurons, synaptic contacts, and supporting cells of Müller were demonstrated by scanning electron microscopy. It was found that the longer the cells survive in culture media they form constantly growing cell aggregates. After 12 days in vitro large multilayered cell complexes covered by an epithelioid cell layer had developed. Merely at the border of such aggregates typical retinal cells could be observed. The occurrence of a dense epithelioid cell layer covering the aggregate of neuronal cells is interpreted as a general adaptational reaction of the cells to the long lasting survival under in vitro conditions.

Animals↗
PubMed1986

[Not Available].

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Anatomy↗
PubMed1986

[Effect and tolerance of daily 2 X 1 g imipenem/cilastatin in general surgery].

The clinical efficacy, tolerability and safety of imipenem/cilastatin were studied in a open, prospective trial with 63 general surgical patients suffering from bacterial infections. According to study criteria, 48 of the patients were evaluable. Clinical cure was achieved in 47 of these 48 patients (97.9%). The causative organisms were eliminated in 39 of the 47 patients cured. Clinical side-reactions were observed in 4.2% of the 63 patients treated. In 8.3% of these laboratory parameters were changed. 77 of the 78 microorganisms isolated before therapy were sensitive to imipenem (MICs 0.02-2.0 mg/l). In one patient a coagulase-negative staphylococcus with an MIC of 16 mg/l was isolated after five days of therapy.

Adult↗
PubMed1986

[Biochemistry of amino acid derivatives of [103Ru] ruthenocene. Comparison with 131I hippuran].

The potential radiopharmaceuticals: ruthenocenoyl alanine, ruthenocenoyl methionine, 1'-methyl-ruthenocenoyl glycine and its esters were labelled with 103Ru starting from the analogous ferrocene compounds. In a series of tests in mice and rats these substances were compared with hippuran and ruppuran (= ruthernocenoyl glycine, a ruthenocene-amino acid analogue of hippuran). The organ distribution of these compounds was measured at various times after injection. Kidney concentrations of 1'-methyl-ruthenocenoyl glycine and its esters were found to be extremely high, followed by a rapid excretion. In contrast with these compounds, ruthenocenoyl methionine indicated a significantly greater affinity for liver than for kidney, but not for pancreas. Ruthenocenoyl alanine exhibits a high affinity for tumor cells. The advantages of 97Ru labelled radiopharmaceuticals compared with 99mTc or 123I/131I labelled compounds are discussed.

Amino Acids↗
PubMed1986

[Amphetamine analog of ruthenocene as a radiodiagnostic agent: brain affinity of ruthenocenoyl-isopropylamine].

N-alkyl derivatives of 1-ruthenocenoyl-2-aminopropane (Rc-amphetamine) were labelled with 103Ru and their organ distributions were measured in mice and rats. All Rc-amphetamines showed a high affinity for brain and lung. A concentration ratio brain/blood up to 17:1 and lung/blood up to 80:1 was measured. The advantages of 97Ru labelled Rc-amphetamine compared to 123I labelled amphetamine for measurement of regional cerebral blood flow are discussed.

Animals↗
PubMed1986

[Effect of derivatives of substance P dipeptide on nerve fiber growth in tissue culture].

Explants and cells from the peripheral (PNS) and central nervous system (CNS) were cultivated in MAXIMOW chambers. The following four derivatives of Substances P (SP) dipeptide were tested for their effects in concentrations between 10(-4) and 10(-8) mol/l: Lys-Pro X 2HBr, Lys(Z)-Pro X HCl, Lys[Z(NO2)]-Pro X HCl and cyclo(Lys-Pro) X HCl. The results suggest that SP and SP derivatives may modulate nerve fibre outgrowth in vitro. In ganglion trigeminale explants Lys(Z)-Pro X HCl stimulated the growth of nerve fibres. The explant covered areas increased significantly. In telencephalon explants and cell cultures the tested derivatives did not essentially promote neurite outgrowth. In retinal cell cultures incubated with cyclo(Lys-Pro) X HCl and Lys[Z(NO2)]-Pro X HCl the neurite outgrowth index was stimulated in a different way. The neurite length was affected and stimulated in the presence of Lys(Z)-Pro X HCl and cyclo(Lys-Pro) X HCl. Both for survival and differentiation PNS neurons depend on specific biofactors. In sensory ganglia explants SP and especially SP derivatives were shown to improve neuronal survival provided that serum or embryonic extract was simultaneously present in the medium. Even if the dipeptides need other biofactors for their full function the may be discussed as neuronotrophic factors because they ensure survival and general growth capability of the responsive neuroblasts.

Animals↗
PubMed1986

[Scanning electron microscopy and light microscopy studies on the retina of chick embryos in cell culture].

Histological and scanning electron microscopy studies (SEM) suggest a classification of neural elements into five main types: receptor cells, bipolar cells, horizontal, amacrine, and ganglion cells in dissociated cell cultures of the retina from 7 to 10 days old chick embryos. By use of SEM the development of the receptor cell inner segments was observed. At the same time many protrusions were noticed at the receptor cell surface. Specific synaptic contacts between the axons of the receptor cells and the dendrites of the bipolar neurons, as well as unspecific contacts between the pericarya of the receptor cells and other dendrites were demonstrated. The bipolar neurons showed smooth cell surfaces, however, the horizontal cells appeared rough on the cell surfaces. Müller cells were always found adjacent to the photoreceptor cells.

Animals↗
PubMed1986

[Organ distribution of ruthenocenyl biogenic amine derivatives--radiodiagnostic agents for the adrenals and ovaries?].

The organ distribution of 103Ru labelled ruthenocenyl derivatives of tyramine, histamine, benzylamine, phenylethylamine and homoveratrylamine were measured in rats. The derivatives of tyramine, histamine and benzylamine showed a high affinity for the adrenal and ovar. Adrenal/muscle ratios up to 2000:1 were gained but only if the dose was administered i.v. and was below 0.1 mumol/kg. The ruthenocenyl derivatives of tyramine labelled with 103Ru in the ruthenocene moiety or with 14C in the tyramine moiety showed a parallel distribution pattern but completely different from the distribution of 103RuCl3. This indicates that the tyramine derivatives are not destroyed in the body yielding Ru-ions. The advantages of the ruthenocenyl derivatives in comparison with the known amphetamine derivatives labelled with radioactive iodine are discussed.

Adrenal Glands↗
PubMed1985

Ru-labeled ruthenocenoyl-glycine: comparison of clearance with hippuran.

Ruthenocenoyl-glycine (ruppuran) is a metallocene analog of iodo-labeled hippuran. After injection of 103Ru-labeled ruppuran and ruthenocenoyl-1,1'-diglycine in rabbits, measurement with external detectors revealed a very rapid accumulation in the kidneys followed by rapid excretion of the 103Ru activity. By measurement of the radioactivity concentration in plasma and urine samples collected 1-60 min after IV injection, the plasma clearance was calculated and compared with the clearance of 125I-labeled hippuran injected simultaneously. The clearance of ruppuran and ruthenocenoyl-diglycine in rabbits was found to be somewhat higher than that of hippuran. Extrapolating to man (1.73 m3), plasma clearance with both ruthenocene derivatives was approximately 500-600 ml/min. Biochemical data as well as the nuclear properties of 97Ru indicate the usefulness of 97Ru-labeled ruthenocenoyl-glycine as a radiopharmaceutical for kidney function studies.

Animals↗
PubMed1985

Autoradiographical investigations on the affinity of acetyl-(103Ru)-ruthenocene for the adrenal glands of mice.

Whole-body autoradiography was used to investigate the distribution of acetyl-103-ruthenium-(103Ru)-ruthenocene in female mice 2 and 24 h after intravenous application. Two hours after the application of acetyl-(103Ru)-ruthenocene, the nasal mucosa, colon, lung, liver, spleen and especially the adrenal glands were labelled. After 24 h, apart from the absence of labelling of the colon, the labelling pattern did not differ from that obtained 2 h after application. Again, the adrenal glands were particularly strongly labelled. Microautoradiography was performed to investigate the distribution of acetyl-(103Ru)-ruthenocene within the adrenal glands. It was shown that acetyl-(103Ru)-ruthenocene labelling was restricted to the zona reticularis and the inner zona fasciculata of the adrenal cortex. After the stimulation of glucocorticoid synthesis in the adrenal cortex by adrenocorticotropic hormone (ACTH) pretreatment, the labelled area in the zona fasciculata was clearly enlarged. It is concluded that acetyl-(103Ru)-ruthenocene has an affinity for those regions of the adrenal glands where androgen and glucocorticoid synthesis occur.

Adrenal Glands↗
PubMed1985

Sex-dependent organ distribution of radiopharmaceuticals: effect of hormones on localization of acetyl-103Ru-ruthenocene.

This paper demonstrates modification of organ distribution of a radiopharmaceutical, acetyl-103Ru-ruthenocene, by competing drugs. This radiopharmaceutical concentrates in kidneys of male Wistar rats 15-fold higher than in females of the same strain and age. This concentration in the male is age-dependent. Moreover, the retention of that radiopharmaceutical in male rats' kidneys is markedly reduced by pre-treatment of the rats with estradiol, and this effect is dose-dependent. Estradiol is competetively inhibiting the retention of acetyl-ruthenocene by the kidneys, the same effect also being obtained by tamoxifen, an anti-estrogen used clinically for regression of mammary carcinoma. Blocking the retention of acetyl-ruthenocene was also obtained by testosterone and cyproterone-acetate, as well as by ovariectomy, but the block after castration was partially compensated with time. Blood clearance of acetyl-ruthenocene is biphasic, with a first t 1/2 of about 12 h, and a second t 1/2 of about 48 h. The retention of the label is sex-specific also in mice, but only the female mice show a high adrenal affinity and significant changes in its organ distribution. These effects may be due to competition of acetyl-ruthenocene for steroid receptors, or due to its activation of enzymes that are responsible for its transformation into a bindable moiety.

Animals↗