Pressure to be a role model.
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Biomedical subjects
Publications and source records attributed to D Hicks.
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Posttransplantation lymphoproliferative disorder is a serious complication of organ transplantation. This disorder has been linked to Epstein-Barr virus infections and can involve the transplanted organ. In the past the diagnosis of posttransplantation lymphoproliferative disorder in heart transplant recipients involving the transplanted organ was made primarily at autopsy. A case of a patient with posttransplantation lymphoproliferative disorder in whom the diagnosis was made initially by endomyocardial biopsy with confirmation by application of molecular techniques on mediastinal lymph node tissue and who was subsequently treated successfully is reported.
The efficacy of a new sustained-release formulation of diltiazem was examined in a placebo-controlled, double-blind trial in patients with stable angina. Doses of 60 mg BID, 90 mg BID, 180 mg BID and 240 mg BID were compared with placebo in 208 patients at 3 hours and 12 hours after dosing. Diltiazem, in doses of 90 mg BID and 180 mg BID, was statistically superior to placebo with respect to increasing total exercise time. Treadmill exercise time at 3 hours postdose increased with placebo from 356.1 +/- 118.7 sec to 375.7 +/- 119.8 sec (NS); with 90 mg BID, 382.7 +/- 111.8 sec to 445.4 +/- 117.5 sec (P < 0.005); and with 180 mg BID, 386.8 +/- 145.9 sec to 467.2 +/- 166.2 sec (P < 0.0001). At 12 hours postdose, treadmill exercise time with placebo increased from 357.6 +/- 128.3 sec to 383.8 +/- 128.7 sec (NS); with 90 mg BID, 395.2 +/- 119.4 sec to 449.7 +/- 123.1 sec (P = 0.053); with 180 mg BID, 395.3 +/- 141.4 sec to 476.6 +/- 165.6 sec (P < 0.0001). Time to onset of angina was also increased by the 180-mg-BID dose both at 3 hours postdose (257.3 +/- 126.8 sec to 354.3 +/- 158.7 sec; P < 0.0001) and at 12 hours postdose (274.7 +/- 131.2 sec to 377.4 +/- 186.2 sec; P < 0.0001). Sustained-release diltiazem is effective and safe in treating patients with chronic stable angina.
The relationship between pharmacodynamic effect and plasma concentrations of the analgesic bromfenac was assessed retrospectively. The drug was administered in single doses of 5, 10, 25, 50, or 100 mg to patients with oral surgery pain. Concentration-effect curves were generated by a semiparametric pharmacokinetic-pharmacodynamic procedure. The bromfenac EC50 (the effect site concentration giving 50% of the maximum effect) was estimated to be 0.36 microgram/ml in patients when all five dose groups were combined, and an Emax model was used for pharmacodynamic response. A similar EC50 value, 0.40 microgram/ml, was obtained when bromfenac was tested in a mouse pain model. On the basis of combined-dose data, effect site concentrations were predicted to be above the analgesic EC50 for approximately 7-8 hours after a 50-mg bromfenac dose was taken in the fasting state. Predictions based on a pharmacokinetic-pharmacodynamic modeling procedure were in reasonable agreement with the clinical observations.
Ganglioside (GG) and neurotrophic growth factor (GF) interactions in retinal neuronal and glial cells have been very little studied. Rat retinas were mechanically separated into outer (photoreceptor or PR) and inner (other neurons, IR) halves by planar vibratome sectioning and retinal Müller glial (RMG) cells were isolated and cultured according to previously published methods. The distribution on a percent molar basis of individual GG was different between the two halves: PR were dominated by GD3 (48% total GG) and contained only trace amounts (< 4%) of complex species (GT1b, GQ); IR was more typical of mature brain tissue, exhibiting substantial amounts (approximately 25%) of more complex GG. The GG profile of RMG cells was also simple, dominated by GM3 (60%) and GD1a (20%). A single addition to the medium of 500 pM bFGF or EGF for 48 hr to cultured RMG cells led to significant increases in total GG levels of 30-40%. Such treatments by both growth factors induced increases in GM3, whereas longer exposure (96 hr) of confluent RMG to these factors additionally stimulated synthesis of more complex GG. Incubations of RMG with [3H]-glucosamine showed that GG synthesis was 2-fold stimulated by growth factors. We also tested the effect of GM3 on one of the bFGF receptor transduction pathways, namely PI-3 kinase activation. To our knowledge these data constitute the first demonstration of neurotrophic factor stimulation of GG levels in cells of CNS in vitro. Such complex interactions may have particularly important consequences for neural physiopathology.