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Biomedical subjects

F Ruch

Publications and source records attributed to F Ruch.

At least 19 recordsLinked to original sources
PubMed2000

Preparation of Micrometer Size Budesonide Particles by Precipitation.

Particles of different shape, size and crystallinity of budesonide, a hydrocortisone streroid, were prepared by precipitation. The method is based on taking advantage of the different solubility of this material in certain organic solvents (ethanol, acetone) and water or alcanes. In principle, to solutions of budesonide, water was added until the solids precipitate or the same solute in mixed solvents was carefully separated by evaporation of the more volatile component at room temperature. The morphology, size, and stability of the resulting particles were sensitive to the evaporation technique, stirring, and presence of a stabilizing agent. Copyright 2000 Academic Press.

Journal Article↗
PubMed1996

Age-related difference in tamoxifen disposition.

PURPOSE: To investigate the pharmacokinetic aspects of tamoxifen, such as the pharmacokinetic-pharmacodynamic (toxicity and clinical response) relationship and the influence of hepatic dysfunction, age, treatment duration, and associated chemotherapy on tamoxifen pharmacokinetics. PATIENTS AND METHODS: Three hundred sixteen patients with breast cancer (247 postmenopausal women) were investigated. Mean age was 58 years (age range, 29 to 85 years). One hundred seventeen patients received tamoxifen as single therapy (adjuvant, 60; neoadjuvant, 17; metastatic, 40); 292 of 316 received 30 mg daily. We obtained 794 blood samples at steady state. Tamoxifen and metabolites, N-desmethyltamoxifen, N-desdimethyltamoxifen, primary alcohol, and 4-hydroxytamoxifen were measured by HPLC. RESULTS: Serum concentrations of tamoxifen and metabolites showed a wide asymmetrical distribution. Median and extremes were 347 nmol/L (not detectable [ND] to 1677) for tamoxifen, 572 nmol/L (ND to 3132) for N-desmethyltamoxifen, 109 nmol/L (ND to 795) for N-desdimethyltamoxifen, and 59 nmol/L (ND to 390) for primary alcohol. 4-Hydroxytamoxifen was detectable in 9.5% of the samples (ND to 162 nmol/L). Neither the absolute nor the relative concentrations of each compound showed significant variations during treatment. Chemotherapy concomitant with tamoxifen slightly increased the tamoxifen blood concentration. Hepatic dysfunction had no obvious effect on drug concentrations, an exception being a slight reduction in the relative proportion of tamoxifen. The influence of age revealed that concentrations of tamoxifen and metabolites increased significantly with age: women younger than 40 years had a tamoxifen plus metabolite median concentration of 802 nmol/L compared with 2428 nmol/L for women older than 80 years. In the 28 patients in whom tamoxifen-related side effects developed, the proportion of demethylated metabolites was higher than that in patients in whom toxicity did not develop. There was no difference in drug concentrations between responding and nonresponding patients. CONCLUSION: Despite the tremendous interpatient variability in drug concentrations, the present data show that tamoxifen and metabolite concentrations significantly increase with age.

Adult↗
PubMed1984

The DNA content of cerebral cortex neurons. Determinations by cytophotometry and high performance liquid chromatography.

Previous work from our laboratories has indicated that the DNA content of rat cerebral cortex neurons increases postnatally to a level of slightly above 3c, where 2c denotes the diploid DNA complement. We have re-evaluated this concept by using various cytophotometric assays and a novel high performance liquid chromatography (HPLC) technique. The latter consists of digesting the DNA in isolated neuronal nuclei by a mixture of DNA-degrading enzymes followed by analysis of the resulting deoxynucleosides by HPLC. We find that the various methods fall into two groups. The first gives evidence of a postnatal DNA (or histone) increase, while the second does not. The first group (DNA increase) comprises cytofluorometry for DNA following Schiff-type staining with fluorochromes 2,5-bis-(4-aminophenyl)-1,3,4-oxadiazole (BAO) and pararosaniline, ultraviolet absorption scanning for DNA and cytofluorometry for histones following staining with sulfaflavine at pH 8. The second group (no DNA increase) consists of cytofluorometry for DNA following staining with the DNA-complexing agents mithramycin, chromomycin A3, 4',6-diamidino-2-phenylindole (DAPI) and bisbenzimide (Hoechst 33258), as well as the newly developed HPLC technique. Since the HPLC technique measures DNA by a direct chemical approach without interference from other nuclear constituents or from higher order packaging in the chromatin, and detects at least 94-95% of the total DNA contained in neuronal nuclei independent of the developmental stage, we infer that the HPLC technique and, by consequence, the cytochemical assays of the second group reflect true DNA values. Therefore, we propose that cerebral cortex neurons retain a diploid DNA level throughout development.

Animals↗
PubMed1983

Cytofluorometric DNA base determination for the investigation of heterochromatin and heterochromatin amplification.

The measurement of chromomycin A3/DAPI fluorescence ratios is shown to allow base content determinations in eu- and heterochromatic regions of interphase cell nuclei. The base content values obtained in chromocenters and euchromatin of Scilla sibirica agree with those measured earlier [12] on the band and non-band areas of the chromosomes of this species. In Sinapis alba three different heterochromatin types, with regard to base content, can be discerned. The heterochromatin amplification observed in the polyploid nuclei of Sinapis roots and hypocotyl involves either all three heterochromatin types, with little resulting change of the total nuclear base content, or only one or the other of them, with a measurable shift of the base content.

Adenine↗
PubMed1979

The fluorescence and bright field microscopic demonstration of cathepsin B in human fibroblasts.

Cathepsin B was demonstrated cytochemically in human fibroblasts with Z-Ala-Arg-Arg-2-(4-methoxy)naphtylamide as substrate. The enzyme was visualized in the bright field microscope with the diazonium salt Fast Blue B as coupling reagent and in the fluorescence microscope with 5-nitrosalicylaldehyde. With both methods cathepsin B was found in small granules distributed throughout the cytoplasm.

Carcinoma, Squamous Cell↗
PubMed1978

Selective excitation of mithramycin or DAPI fluorescence on double-stained cell nuclei and chromosomes.

Fluorescence spectra of leukocytes stained by both mithramycin and DAPI showed that the fluorescence of the two dyes can be separated efficiently by using different excitation wavelengths, for instance the 435 nm and the 365 nm mercury lines. In human chromosomes the complementary ("reverse") banding pattern produced by these dyes may thus be observed on double stained chromosome spreads. In plants, for instance in Anemone blanda, the two dyes may reveal two different banding patterns. The results of absorption and fluorescence measurements suggest the existence of at least two binding sites, or types, for each dye, with different fluorescent yields and binding strengths.

Amidines↗
PubMed1978

Cytophotometric study of nuclear differentiation during pollen development in Tradescantia paludosa.

During pollen development the dry weight, total protein, histone, DNA, arginine, and lysine content were analysed by cytophotometric methods in partially isolated nuclei. The amount of analysed substances increased from the end of the meiosis to the mitosis of the microspores to the double of the initial values. After mitosis the ratio histone/DNA remained almost unchanged in both vegetative and generative nuclei. On the other hand a large difference in the ratio non-histone protein/DNA could be observed, the vegetative nucleus containing more non-histone protein than the generative nucleus. The rate of RNA synthesis being higher in the vegetative nuclei, these non-histone proteins may have some function in nuclear activation. The DNA of the generative nucleus is duplicated before anthesis, whilst in the vegetative nucleus the DNA content remains constant.

Arginine↗