Biomedical subjects

J R Thomas

Publications and source records attributed to J R Thomas.

At least 73 records · Page 4Linked to original sources

PubMed1996

Identification of a GDP-Fuc:Gal beta 1-3GalNAc-R (Fuc to Gal) alpha 1-2 fucosyltransferase and a GDP-Fuc:Gal beta 1-4GlcNAc (Fuc to GlcNAc) alpha 1-3 fucosyltransferase in connective tissue of the snail Lymnaea stagnalis.

Connective tissue of the freshwater pulmonate Lymnaea stagnalis was shown to contain fucosyltransferase activity capable of transferring fucose from GDP-Fuc in alpha 1 -2 linkage to terminal Gal of type 3 (Gal beta 1-3GalNAc) acceptors, and in alpha 1-3 linkage to GlcNAc ot type 2 (Gal beta 1-4GlcNAc) acceptors. The alpha 1-2 fucosyltransferase was active with Gal beta 1-3GalNAc beta 1-OCH2CH=CH2 (Km = 12mM, V(max) = 1.3 mUml-1) and Gal beta 1-3GalNAc (km =20 mM, V(max) = 2.1 mUml-1), whereas the alpha 1-3 fucosyltransferase was active with Gal beta 1-4GlcNAc (Km = 23 mM, V(max) = 1.1 mUml-1). The products formed from from Gal beta 1-3GalNAc beta 1-OCH2CH=CH2 and Gal beta 1-4GlcNAc were purified by high performance liquid chromatography, and identified by 500 MHz 1H-NMR spectroscopy and methylation analysis to be Fucalpha1-2Gal beta 1-3GalNAc beta 1-OCH2CH=CH2 and Gal beta 1-4(Fucalpha1-3)GlcNAc, respectively. Competition experiments suggest that the two fucosyltransferase activities are due to two distinct enzymes.

Animals↗

PubMed1996

Telomeric associations in the progression of chromosome aberrations in pediatric solid tumors.

Telomeric association (tas) is a cytogenetic phenomenon in which chromosome ends fuse to form dicentric, multicentric, and ring chromosomes. We observed clonal tas in six pediatric solid tumors of various types and histological grades studied using short-term in situ culture and G-banding techniques. These tumors included a neurilemoma, an undifferentiated (embryonal) sarcoma of the liver (UESL), two anaplastic astrocytomas (AA), one case of glioblastoma multiforme (GBM), and a neuroblastoma (NB) of the kidney. Cytogenetic data from all six tumors demonstrated multiple numerical and structural aberrations including tas. The tas appeared to be a secondary aberration in these tumors, however, it was possible to follow the progression of the telomeric chromosome aberrations in several cases. In all but one case (UESL) the loss of chromosome segments occurred. Tas of 11p was observed in three of the six tumors, two of which showed the subsequent loss of 11p (AA and AB). In addition, tas of 4p was seen in three tumors, two of which showed clonal tas of 4p with 22q. Tas of 10p, 21p, and 22q were all observed in at least two different tumors. The clonal telomeric fusions of 4p with 22q, recurring tas of 11p, and the subsequent loss of the short arm of 11 demonstrated here, suggests that some chromosome regions are subject to nonrandom instability and sometimes loss.

Adolescent↗

PubMed1996

Comparison of hetastarch with albumin for postoperative volume expansion in children after cardiopulmonary bypass.

OBJECTIVE: Hetastarch has been studied as a volume expander in adults after cardiopulmonary bypass (CPB) and in recommended dosages has not altered coagulation studies or increased clinical bleeding. Hetastarch was compared with albumin in children after CPB to determine whether hetastarch use was associated with increased clinical bleeding or alteration of coagulation studies. DESIGN: Randomized double-blinded study. SETTING: University-affiliated children's hospital. PARTICIPANTS: Forty-seven children age 1 year or greater (mean 72.8 months; range 12 months to 15.5 years) scheduled for repair of congenital heart disease with moderate hypothermia were randomized to receive hetastarch or albumin as a postoperative volume expander during the first 24 hours after surgery. INTERVENTIONS: Thirty-eight children required colloid replacement therapy. Blood pressure, central venous pressure, urine output, and chest tube drainage were used to determine colloid requirement. MEASUREMENTS AND MAIN RESULTS: Clinical bleeding and laboratory studies of coagulation were evaluated as were requirements for colloid, crystalloid, and blood products. Twenty children received 6% hetastarch, and 18 received 5% albumin. No differences were found in the amount of replacement fluids required, or in coagulation parameters in children receiving 20 mL/kg or less of either colloid replacement therapy. An increase in prothrombin time was demonstrated in children who received greater than 20 mL/kg of 6% hetastarch (p = 0.006); however, no difference in clinical bleeding or blood product requirement was demonstrated between the hetastarch or albumin groups receiving more than 20 mL/kg. CONCLUSION: This study demonstrated that 6% hetastarch is safe and an effective plasma volume expander in the postoperative management of children, using volumes up to 20 mL/kg. Close laboratory monitoring and careful evaluation of clinical bleeding are suggested when larger doses of hetastarch are administered because of prolongation of the prothrombin time with more than 20 mL/kg of hetastarch.

Adolescent↗

PubMed1996

Rejuvenation of the skin surface: chemical peel and dermabrasion.

Chemical peel and dermabrasion are traditional, well-proven methods for the rejuvenation of the skin. The medium-depth trichloroacetic acid peel and the deep phenol peel offer distinct advantages and disadvantages and are discussed in detail in this article. The management of complications associated with both peel techniques is also discussed. Regional dermabrasion is an effective adjunct to facial rejuvenative surgery, such as face lift and blepharoplasty. Full-face dermabrasion and spot or local dermabrasion are most often used in the treatment of facial scarring. The technique of dermabrasion is discussed as well as its indications and postoperative care. Results are shown for both dermabrasion and peel.

Administration, Topical↗

PubMed1996

Effects of diet and diet-plus-exercise programs on resting metabolic rate: a meta-analysis.

Studies examining the effects of diet (D) and diet-plus-exercise (DE) programs on resting metabolic rate (RMR) report equivocal results. The purpose of this study was to use meta-analysis to determine if exercise prevents the decrease in RMR observed with dieting. Results from the 22 studies included in this analysis revealed that the majority of studies used female subjects ages 31-45 years, who were fed a relatively low-fat, high-carbohydrate diet of less than 5,023 kJ.day-1. The predominant prescribed exercise was aerobic in nature, 31-60 min in duration, performed 4-5 days per week, and of moderate intensity (51-70% of VO2max). Contrary to what is reported in narrative reviews, RMR decreased significantly with both D and DE programs, and the drop with D was significantly greater than that with DE. In conclusion, the addition of exercise to dietary restriction appears to prevent some of the decrease in RMR observed in premenopausal women.

Adult↗

PubMed1996