Biomedical subjects

T K Williams

Publications and source records attributed to T K Williams.

12 recordsLinked to original sources

PubMed1992

Experimental model of human light-chain-associated disease.

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Animals↗

PubMed1990

Health behavior correlates of depression in a sample of high school students.

Frequency of symptoms of depression and selected health-related practices and events were measured in a sample of 219 high school students. Students reported numerous symptoms of depression. Relative proportions of boys and girls reporting symptoms of depression were not significantly different. However, girls reported experiencing more severe depression than their male counterparts. Depression correlated significantly with several of the 22 health practices and states of affect examined. Both the determinants and manifestations of depression in adolescent cohorts require in-depth investigation. Possible implications for school health personnel are discussed.

Adolescent↗

PubMed1988

Conversion of xanthine dehydrogenase to oxidase in ischemic rat intestine: a reevaluation.

Oxygen radicals derived from xanthine oxidase (XO) are important mediators of the cellular injury associated with reperfusion of ischemic intestine, stomach, liver, kidney, and pancreas. XO exists in nonischemic tissue predominantly as xanthine dehydrogenase (XDH) and converts to oxygen radical-producing XO with ischemia. Grinding intestine under liquid nitrogen and placing the powder in phosphate buffer (pH 7.0) containing thiol reductants and protease inhibitors adequately preserved total XDH + XO activity and the percentage in the oxidase form (%XO) for 24 h. Total activity in nonischemic intestine ranged from 374 nmol.min-1.g-1 in duodenum to 138 nmol.min-1.g-1 in ileum, while XO activity was approximately 19% of total activity throughout the entire small intestine. The rate of XDH conversion to XO during normothermic ischemia varied only slightly throughout the intestine, increasing 13% per hour to 34, 46, and 61% XO after 1, 2, and 3 h of ischemia, respectively. Our results contrast with previous reports where XDH conversion to XO occurred within 60 s ischemia but are consistent with physiological and morphological evidence of ischemic injury and provide further support for involvement of XO in intestinal injury associated with ischemia.

Animals↗

PubMed1987

Regulation of ecdysone biosynthesis in the tobacco hornworm, Manduca sexta: titre of the haemolymph stimulatory factor during the last larval instar.

A recently isolated haemolymph protein appears to be an important regulator of ecdysone biosynthesis by prothoracic glands in Manduca sexta. Using a dose-response titration protocol, the haemolymph titre of this stimulatory factor was determined during the last larval instar. The titre was high (greater than 2.0 U ml-1) on days 0 and 1, then dropped significantly to 0.55 U ml-1 on day 2, and remained depressed until day 4. The titre of the stimulatory factor then increased to a peak of 1.62 U ml-1 on day 7, and remained elevated (approx. 1.1 U ml-1) until the end of the instar. A set of physical and biochemical criteria was used to confirm that the stimulatory activity present in haemolymph on different days of the instar represented the presence of the factor. The data are consistent with the hypothesis that fluctuations in the titre of the haemolymph stimulatory factor play a critical role in regulating ecdysone biosynthesis during larval-pupal development.

Animals↗

PubMed1984

Radioimmunoassay of fragment E-related neoantigen: validation studies and clinical application.

Measurement of fibrinogen-fibrin degradation products (FDP) levels in plasma may provide a direct index of plasmin action, and increased levels of FDP would indicate coagulopathy. We have established an E-neoantigen radioimmunoassay ( Eneo RIA) that can determine normal and pathological plasma levels of E-related FDP. The assay employs rabbit antiserum produced against fragment E derived from a plasmin digest of fibrinogen and subsequently absorbed with fibrinogen. The absorbed antiserum contains antibodies which are equally reactive with fibrinogen derived E (Fg-E) and fibrin derived E (Fb-E) but not with fibrinogen at 1 mg/ml. The Eneo RIA was validated by assay parallelism and by recovery experiments. Plasma Eneo immunoreactivities in 14 normals were 4-22 ng/ml (mean 12.7 ng/ml). Plasma Eneo levels in 23 of 24 patients with neoplastic and haematological diseases were elevated above normal (range 27-2027 ng/ml). Unusually high Eneo values were observed with three patients whose diseases were complicated by either disseminated intravascular coagulation (DIC) or deep vein thrombosis. After heparin therapy, the Eneo level of a patient with chronic DIC declined. A pathological plasma was eluted from a Sephadex G-200 column and Eneo immunoreactivity was determined on the eluates. The gel filtration pattern of Eneo indicates that E-related FDP is a family of plasmic fragments derived from crosslinked fibrin.

Anticoagulants↗

PubMed1981

Comparisons of hemagglutination inhibition, staphylococcal clumping, and latex agglutination tests for canine fibrinolytic degradation products.

Two assay systems for fibrinogen-fibrin degradation products (FDP) in canine serum, the glutaraldehyde erythrocyte hemagglutination-inhibition immunoassay (GEHII) and the staphylococcal clumping test (SCT), were compared for reactivity with the plasmin digests of canine fibrinogen and with sera obtained from dogs suspected of having circulating FDP, The GEHII reacted well with early and late plasmin digests of fibrinogen. With early-stage fibrinogen digests, the SCT was more reactive than was GEHII. However, after the appearance of D and E fragments in the digests, SCT reactivity decreased progressively during plasminolysis. The sensitivities of GEHII and SCT for assaying FDP were 0.5 and 0.125 microgram of fibrinogen equivalent/ml, respectively. Serum FDP values for dogs with desease were comparable, with values ranging from 1 to 122 micrograms/ml by GEHII and 8 to 64 micrograms/ml by SCT. One dog with fulminating disseminated intravascular coagulation had a serum FDP value of 128 micrograms/ml by SCT and 179 micrograms/ml by GEHII. Howeever, normal canine sera had values by SCT of 4 to 16 micrograms of fibrinogen equivalent/ml, whereas normal values by GEHII were 0.5 to 2 micrograms/ml. Serum FDP concentrations were also determined for healthy and diseased dogs by latex-agglutination test. The dog with fulminating disseminqated intravascular coagulation had a FDP value of greater than 40 micrograms/ml, and only 1 other diseased dog had greater than 10, but less than 40 micrograms of fibrinogen equivalent/ml. All other dogs were considered negative, with FDP values of less than 10 micrograms/ml.

Agglutination Tests↗

PubMed1975