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Biomedical subjects

J J Ryan

Publications and source records attributed to J J Ryan.

At least 235 records · Page 13Linked to original sources
PubMed1976

Chemical confirmation of diethylstillbestrol residues in beef livers.

A simple chemical technique was developed to confirm the presence of diethylstillbestrol (DES) residues in beef tissues at 2 ppb. The DES-trifluoroacetate (TFA) from the previously published method is hydrolyzed in water-methanol at 55 degrees C for 20 min to free DES which is then extracted into benzene. Trimethylamine and a small amount of heptaafluorobutyric (HFB) anhydride are added to effect the smooth conversion of DES to its di-HFB at either room temperature or 60 degrees C. DES-HFB is determined by gas-liquid chromatography with electron capture detection on a 6' x 4 mm id column of 3% OV-210 at 190 degrees C. This procedure yields 2 peaks for DES-HFB (retention times 2.7 and 4.8 min for the cis and trans, respectively) which are resolved from the 2 DES-TFA peaks (retention times 2.3 and 3.3 min for cis and trans, respectively). The sensitivity of detection of DES-HFB is increased by a factor of 4-5 over that for DES-TFA. This chemical technique was successfully applied to purified extracts of beef liver fortified with DES at 2-10 ppb with recoveries from 60 to 110%.

Animals↗
PubMed1975

Clonorchis sinensis and pancreatitis. Twenty-five after endemic exposure.

Clonorchis sinensis is an aften-cited but rarely reported cause of acute pancreatitis. We report a patient with Clonorchis infestation detected 24 years after leaving the endemic area, in whom the parasite is a likely cause of pancreatitis. Recognizing the popularity of the Cantonese style of Chinese cooking and noting relaxation of travel restrictions to the endemic areas, we feel Clonorchis should be sought in the obscure case of pancreatitis, especially in Orientals and travelers who have lived in the endemic area.

Adult↗
PubMed1975

A screening method for determining nitrofuran drug residues in animal tissues.

A method was developed for measuring low levels of total nitrofurans in animal tissues and milk. The antimicrobial nitrofurans (5 or more products) used in agriculture are extracted from tissue with aqueous acid in the presence of ethyl acetate. After centrifugation and evaporation, the organic residue is washed with hexane and the nitrofurans are hydrolyzed to 5-nitrofuraldehyde in aqueous acid at 70 degrees C. The hydrolysis product is extracted with benzene and measured by gas-liquid chromatography with electron capture detection. Recoveries of nitrofurazone and furazolidone from fortified poultry and swine tissues at the levels of 0.5 and 0.1 ppm are 75 and 65%, respectively. This procedure can be used to detect the total nitrofuran content of as little as 10 ppb muscle tissues and milk, 100 ppb liver, and 50 ppb fat with no interference from related veterinary nitrodrugs.

Adipose Tissue↗