Biomedical subjects

J Blome

Publications and source records attributed to J Blome.

6 recordsLinked to original sources

PubMed2001

Time-space sampling in minority communities: results with young Latino men who have sex with men.

OBJECTIVES: This study addressed methodological issues influencing the feasibility of time-space sampling in HIV prevention studies targeting hard-to-reach populations of minority young men who have sex with men (MSM). METHODS: We conducted interviews with 400 men in 32 venues where young Latino MSM congregate in New York City. Response rates and demographic and sexual risk profiles are compared by venue type. RESULTS: More than 90% of the men approached were screened. Among eligible men, participation rates exceeded 82%. Participation was higher at special events and gay venues compared with nongay venues (P < .05). Young MSM in nongay venues were less likely to self-identify as gay (P < .01) or to report recent anal sex with a male (P < .10). Condom use did not vary by venue type but was lower with women than with men. If surveys had been limited to gay venues, about half of the young MSM surveyed in nongay venues would have been missed. CONCLUSIONS: Time-space sampling of a relatively "hidden" minority young MSM population can be successful across a range of venues. However, the benefits of greater outreach must be weighed against the costs incurred recruiting participants in nongay venues.

Adolescent↗

PubMed2000

High-performance liquid chromatographic separation and measurement of various biogenic compounds possibly involved in the pathomechanism of Parkinson's disease.

The work presented here describes an optimised, reversed-phase high-performance liquid chromatographic (RP-HPLC) method for separating 46 biogenic compounds, which, as neurotoxins or as their precursors or derivatives, may be relevant in the pathomechanism of Parkinson's disease. In some cases, the physico-chemical properties of these substances are very similar, in other cases they differ greatly. In order to facilitate their detection in one chromatographic run, ion-pair chromatography was uniquely combined with a gradient elution. A diode array or a dual wavelength detector was used in combination with a fluorescence detector to verify the identity of the compounds.

Chromatography, High Pressure Liquid↗

PubMed1997

Enantioselective high-performance liquid chromatography assay of (+)R- and (-)S-alpha-lipoic acid in human plasma.

A specific plasma level assay for the enantiomers of alpha-lipoic acid is described. It makes use of liquid-liquid extraction, chemical reduction to the dithiol enantiomers, and their precolumn chiral derivatisation with o-phthalaldehyde in the presence of D-phenylalanine. The two diastereomeric derivatives are separated by reversed-phase HPLC with fluorescence detection. The working range of the assay is between 15 ng/ml (lower limit of quantitation) and 1,000 ng/ml for either enantiomer.

Calibration↗

PubMed1986

A sensitive, fast, durable, highly selective method for the determination of amino acids and biogenic amines in the cerebrospinal fluid and other body fluids and tissues.

A sensitive, fast, durable HPLC method with high resolution for the determination of amino acids and some biogenic amines is described. It allows the simultaneous determination of more than 40 substances in the cerebrospinal fluid or other body fluids or tissues. The method allows to measure both, the free and the conjugated amino acids. It detects 5 X 10(-13) g of most amino acids and measures the relevant substances in their physiological concentrations with less than 0.1 ml cerebrospinal fluid. The precision is 1-2%.

Amino Acids↗

PubMed1982

[Not Available].

Explore the source record for details and available documents.

Botany↗

PubMed1982

[Comparative study of the bioavailability and the pharmacodynamic effect of five allopurinol preparations (author's transl)].

The aim of this study was to determine the relative bioavailability of five oral allopurinol preparations and evaluation of the pharmacodynamic effect. Included were two slow-release formulations. The study was performed as complete five-way randomized steady-state cross-over trial in 10 healthy volunteers. Each day 300 mg of 1H-pyrazolo-(3,4-d) pyrimidin-4-ol (allopurinol) were orally administered for 7 days, followed by a wash-out phase of 14 days. The minimal serum levels of allopurinol and its major metabolite oxypurinol were determined by HPLC. In parallel the concentrations of uric acid in blood and in 24-h urine were measured. The two slow-release formulations had a significantly lower relative bioavailability compared to the normal formulations and, moreover, a slow-release effect could not be demonstrated. In all cases the clinical effect of the test preparations could be demonstrated, and a correlation between bioavailability and pharmacodynamic effect could be calculated. A correlation between published in vitro data and the present in vivo data could not be found.

Adult↗