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Results for “Sulfur Radioisotopes”

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At least 19 recordsLinked to original sources
PubMed1985

Mucosubstance histochemistry in control and acid-stressed epidermis of brown bullhead catfish, Ictalurus nebulosus (LeSueur).

Glycoprotein components of epidermal mucous cells in control (pH 6.8) and acid-stressed (pH 5.8, 4.8, 4.0) brown bullhead catfish were studied by histochemical and autoradiographic methods. Following exposure to acid, increased numbers of epidermal mucous cells were noted in all tissue sites studied, particularly dorsal and ventral skin. Mucous cells of control fish and acid-stressed (pH 5.8) fish contained a mixture of neutral and acidic mucosubstances, the latter including both sialomucins and sulfomucins, with sialomucins predominating. An apparent shift toward increased sulfomucin production was observed in skin from fish exposed to pH 4.8 and 4.0. In addition, autoradiographic studies using 35S showed increased labeling of mucous cells in acid-exposed (pH 4.0) epidermis, offering further support for a shift toward sulfomucin production in acid-stressed fish. Absence of appreciable sulfomucin production in younger fish (less than 1 year old) suggested that this shift may be partly age-dependent. The functional significance of increased sulfomucin production in acid-stressed epidermal mucous cells is uncertain but may be related to maintenance of ionic equilibrium.

Animals↗
PubMed1979

A selected bibliography of biomedical and environmental applications of stable isotopes. V-2H, 13C, 15N, 18O and 34 S, 1977-1978.

The first biennial updated compilation, for the period 1977-1978, of selected references to the use of 2H, 13C, 15N, 18 O and 34S in biochemical, pharmacological, clinical and environmental applications is presented. Author and subject indices for this information are compiled to enable the reader to make further use of these references.

Bibliographies as Topic↗
PubMed1993

Papillomavirus screening in cervical cell samples using dual-label dot-blot analysis.

The presence of human papillomavirus (HPV) in cervical cells is closely related to the development of cervical carcinoma. Detection of virus may be by Southern blot, dot blot or the highly sensitive polymerase chain reaction. Whatever method is employed, there are problems of false negatives due to poor clinical samples in which the DNA may be degraded or is absent altogether. Here we describe a new method of dual labelling for dot blots using a 32P-labelled probe for HPV and a 35S-labelled probe for human actin genes. The samples were counted on a Beta-plate flat-bed scintillation counter and the data analysed to separate the activities of the two isotopes. The counts from the actin probe show whether human DNA is present or not and false negatives from this cause may thereby be eliminated. The counts due to HPV when compared with those for actin give a quantitative measure of HPV abundance for the particular sample and this may have clinical relevance.

Actins↗
PubMed1986

Gene mapping on human metaphase chromosomes by in situ hybridization with 3H, 35S, and 32P labeled probes and transmission electron microscopy.

A method based on in situ hybridization, autoradiography and transmission electron microscopy for mapping genes on human metaphase chromosomes is presented. Successful mapping of the tandemly repeated rDNA genes and of two nucleic acid probes, N-myc and probe 3 (Kanda et al. 1983), that are amplified in a homogeneously staining region (HSR) of the neuroblastoma cell line, IMR-32 is described. By using sufficiently thin AgBr emulsions, it is possible to obtain observable grains and good resolution with probes radiolabeled with 3H, 35S, or 32P, but the former gives the best results. We observe that neither of the two probes, N-myc and probe 3, has a uniform spatial distribution along the HSR and that the distributions of the two probes differ from each other. These observations support previous studies which indicated that the formation of an HSR is a more complex process than uniform amplification of a single DNA segment to form an n-fold set of perfect tandem repeats. The present study shows that the electron microscopic method is useful for extending the results of light microscopic studies for problems where higher resolution mapping is needed.

Cell Line↗
PubMed1990

Proteoglycan metabolism in isolated chondrocytes from human cartilage. Influence of niflumic acid.

The effect of niflumic acid on hyaluronic acid and proteoglycan metabolism of human cartilage cells was investigated in vitro. Cartilage cells were obtained from five different donors. Niflumic acid levels used in the test systems ranged from 0 to 22 microgramsr/ml and were comparable to serum concentrations in humans after oral intake. Niflumic acid increased the synthesis rates of proteoglycan in some batches of isolated and monolayer-cultured chondrocytes. The effect on hyaluronate synthesis was less pronounced. The fact that this increase in the synthesis of proteoglycan was restricted to some of the donors whereas isolated cells or tissue samples from other individuals remained unaffected illustrates the heterogeneity of different human donors. Depression of proteoglycan synthesis in the presence of the drug was never observed.

Carbon Radioisotopes↗
PubMed1983

Comparisons using 35S- and 32P-labeled DNA for hybridization on nitrocellulose filters.

DNA was labeled by nick translation with 35S and used as a probe in Southern- or colony-blot DNA hybridization. Comparison with DNA labeled with 32P showed that not only was 35S-labeled DNA suitable as a probe, but in many cases had advantages. The longer half-life of 35S allows for less stringent timing of experiments and eliminates the waste of unused old label. Resolution on autoradiographs was found to improve when using 35S-labeled DNA.

Chemical Phenomena↗
PubMed1986

Preparation of tyrosine-O-[35S]sulfated cholecystokinin octapeptide from a nonsulfated precursor peptide.

A rapid and simple one-pot method for O-sulfation of nonsulfated cholecystokinin octapeptide (CCK-8) was developed using sulfuric acid and dicyclohexylcarbodiimide (DCC) without protection of the amino acid side chains. The extent of sulfation was increased with increasing the amount of reactants, sulfuric acid, and DCC, and reached maximum (40%) with fourfold molar excess of sulfuric acid and 40-fold molar excess of DCC. The excess of nonsulfated peptide inhibited the sulfation. The sulfation product was purified by HPLC or TLC to give a pure sulfated substance which showed exactly the same behavior as that of an authentic O-sulfated CCK-8 on HPLC or TLC. The purified sulfated peptide was active in stimulating amylase secretion from rat pancreatic fragments, and amino acid analysis showed that the tyrosine residue in the peptide existed in O-sulfated form. Sulfation with [35S]sulfuric acid-DCC produced a radioactive substance, from which O-[35S]sulfated CCK-8 could be easily purified by two-dimensional TLC.

Cholecystokinin↗
PubMed1989

Preparation of [35S]sulfobromophthalein of high specific activity.

Study of the hepatocyte transport mechanism of organic anions such as bilirubin and sulfobromophthalein has been limited by the relatively low specific activities of these ligands. [3H]Bilirubin and [35S]sulfobromophthalein have been available with specific activities of only approximately 100 mCi/mmol. We now report a relatively simple procedure to prepare [35S]sulfobromophthalein at a specific activity of approximately 3000 mCi/mmol. This compound is radiochemically pure and serves as a tracer for authentic sulfobromophthalein as judged by chromatography, hepatocyte uptake, metabolism, and biliary excretion. Use of this material as a photoaffinity probe and as a transported ligand may permit dissection and understanding of its transport mechanism.

Animals↗
PubMed1993

Compartmentation of intestinal drug sulphoconjugation. Incorporation of luminal and contraluminal [35S]sulphate into 1-naphthol by the isolated mucosa of guinea pig jejunum and colon.

Compartmentation of 1-naphthol metabolism was inferred from the metabolite pattern and distribution in the isolated mucosa of guinea pig intestine mounted in a flux chamber (Sund and Lauterbach, Arch Pharmacol Toxicol 58: 74-83, 1986). To verify the existence of these compartments the dependence of [35S]sulphate incorporation into 1-naphthol sulphate on the side of administration of 1-naphthol and [35S]sulphate was determined. Isolated mucosae were pre-equilibrated with [35S]-sulphate (5 x 10(6) cpm/mumol, 1 mM) for 30 min and subsequently incubated for 15 min with 50 microM 1-naphthol. The three 1-naphthol sulphate fractions (luminal side, blood side and tissue) were assayed by HPLC and liquid scintillation counting; their specific activity was calculated as percentage of the specific activity of the inorganic sulphate administered. 1-Naphthol glucuronide was also measured. In jejunal experiments: after luminal administration of 1-naphthol, 1-naphthol sulphate appeared almost exclusively in the luminal solution; its specific activity approached 70% and 3%, when [35S]sulphate was added to the luminal and blood side, respectively. After introducing 1-naphthol and [35S]sulphate on the blood side, a high and similar specific activity of 50-60% was observed in all three 1-naphthol sulphate fractions (luminal and blood side, tissue) though adding [35S]sulphate to the lumen side decreased the specific activity to 10-20%. In experiments on colonic mucosa: a specific activity both of luminal and blood side 1-naphthol sulphate of more than 50% was observed with blood side [35S]sulphate irrespective of the side of 1-naphthol administration. When [35S]sulphate was placed on the luminal side the specific activity of blood side 1-naphthol sulphate dropped to only 3%, and that of luminal 1-naphthol sulphate ranged between 6% and 20%. Supplementary experiments in which mucosae were exposed to 1-naphthol and [35S]sulphate for 45 min without preincubation showed a tendency to decrease the lumen: blood distribution ratio of 1-naphthol sulphate. However, the general pattern of 1-naphthol sulphate specific activity remained unchanged. The experiments provide further evidence that the jejunal conjugation of phenolic drugs is being performed in two major compartments, which are accessible from the lumen ("luminal compartment") and blood ("systemic compartment") side. The luminal compartment seems practically inaccessible to blood side sulphate as is the systemic compartment for luminal 1-naphthol. In the colonic mucosa, a major "systemic compartment" receiving its sulphate from the blood side is the site for most of the events, but a minor "luminal compartment" seems to be involved as well.

Animals↗