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Biomedical subjects

G Stork

Publications and source records attributed to G Stork.

At least 19 recordsLinked to original sources
PubMed2001

[Hemorrhagic acute abdomen due to rupture of splenic artery aneurysm. Tomography contribution in the diagnosis].

Three new splenic artery aneurysm rupture cases are presented insisting on the usefulness of abdominal helicoidal computed tomography (AHCT) with intravenous contrast pump. The three patients presented were hospitalized showing acute abdomen associated with non-traumatic hypovolemic shock. In two of the three cases, abdominal computed tomography was used to arrive at the pre-surgical diagnosis. In one of them the abdominal computed tomography with intravenous contrast pump was used, which showed high specificity for the diagnosis, thus becoming a useful methodology whenever arteriography is not available.

Abdomen, Acute↗
PubMed2000

[Organic synthesis].

Some comments on the problems that are encountered by organic chemists who attempt the total synthesis of a molecule having several asymmetric centers. These difficulties explain the relatively slow progress of that branch of chemistry, although some of its successes merit being considered works of art.

Art↗
PubMed1999

Some contributions to regio and stereo control: from Cincholoipon and Cantharidin to the present.

A condensed review of some of the major original contributions of the author's research group to organic synthesis during more than half a century. The emphasis is on methodology, especially as it involves the control of regio- and stereochemistry. The application of these methods in the total synthesis of specific natural products in the author's laboratory is not discussed in extenso, but only by focusing on certain key steps which illustrate the application of the methods mentioned here. Methods discussed in this fashion are: cationic polyene cyclizations; the enamine alkylation and acylation of ketones and aldehydes; the metalloenamine alkylation; the regiospecific formation and trapping of enolates, via electron addition or via conjugate addition of organometallic reagents to enones; regiospecific enolate formation-trapping from saturated ketones and from beta-alkoxy enones; the epoxynitrile and the allylic epoxynitrile cyclizations; the cyclization of olefinic diazoketones; the cyclization of alkynyl ketones; protected cyanohydrins as acylcarbanion equivalents; the vinyl radical cyclization; the control of regio- and stereochemistry via radical cyclization to temporary rings.

Acylation↗
PubMed1998

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine. II. Enrichment.

A procedure for the enrichment of aromatic amines via solid-phase extraction was developed. A HR-P phase based on styrene-divinylbenzene was used for the investigations, generally followed by derivatization with iodine and determination via GC-ECD. The recoveries of 53 aromatic amines in a drinking water matrix at pH 9 were determined. Most anilines showed relative recoveries between 80-120% with relative standard deviations of< or = 5% at concentration levels between 10 and 20 micrograms 1(-1). The comparison with a wastewater matrix led to similar results. The enrichment procedure was applied to real samples, e.g., samples of ammunition wastewater.

Amines↗
PubMed1998

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine. I. Derivatization.

A new method for the selective determination of aromatic amines is presented, which is based on the solid-phase extraction at pH 9 and subsequent derivatization of the analytes to the corresponding iodobenzenes. These can selectively and sensitively be determined with gas chromatography and electron-capture detection. Separation of at least 30 compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were investigated, and only in six cases no derivatives were obtained. Limits of quantitation were between 0.5 and 8 micrograms 1(-1), but may still be lowered with higher sample volumes or different injection techniques. The application to water samples revealed the suitability for the investigation of ground, leachate and wastewater.

Amines↗
PubMed1998

Highly polar metabolites of nitroaromatic compounds in ammunition wastewater.

Transformation processes of nitroaromatic compounds (NAC) are described that lead to polar and highly hydrophilic metabolites in ammunition waste water. For the identification of proposed metabolites, several analytical methods for the separation and determination of these compounds were developed and applied to the investigation of a former ammunition plant and its surroundings. The compound classes which were investigated include nitro and amino substituted toluenesulfonic acids, nitrobenzoic acids, aminobenzoic acids and nitromethylphenols. Method development was usually done with high performance liquid chromatography and ion pairing or ion suppression techniques. In the leachate water of a disposal site of a former ammunition plant in Stadtallendorf, Germany, 15 compounds from the above-mentioned categories have been found to be present in concentrations up to a few hundred microgram/L. The presence of so many polar compounds suggest that current and future surveying programs should include representative analytes of the investigated categories.

Biotransformation↗