The effects of age on the pharmacokinetic and pharmacodynamic responses to rocuronium (Org 9426) were studied in 20 elderly (> 70 yr) and 20 younger control patients (< 60 yr) during N2O/O2, fentanyl anesthesia. The onset times were the same for both the elderly and younger control group, but the duration of action of rocuronium was significantly prolonged in the elderly patients. Elderly patients, when compared with the younger, also exhibited a significant decrease in plasma clearance (3.67 +/- 1.0 vs 5.03 +/- 1.5 mL.kg-1.min-1, mean +/- SD) and volume of distribution (399 +/- 122 vs 553 +/- 279 mL/kg, mean +/- SD). During the recovery phase of paralysis, no significant difference was seen in the log plasma concentration versus twitch tension response relationship between 20% and 80% paralysis in young and elderly patients receiving rocuronium. The differences in action of rocuronium between the elderly and younger groups can be fully explained by the observed differences in the distribution and elimination of rocuronium between the two groups. The decreased total body water and decreased liver mass which normally accompany aging are likely explanations for the pharmacokinetic changes found in the elderly in this study. We conclude that the action of rocuronium is prolonged in patients aged more than 70 yr because of decreased elimination of the drug.
The effect of obesity on the disposition and action of vecuronium was studied in 14 surgical patients. After induction of anesthesia with thiopental and maintenance of anesthesia by inhalation of nitrous oxide and halothane, seven obese patients (93.4 +/- 13.9 kg, 166% +/- 30% of ideal body weight, mean +/- SD) and seven control patients (60.9 +/- 12.3 kg, 93% +/- 6% of ideal body weight) received 0.1 mg/kg of vecuronium. Plasma arterial concentrations of muscle relaxant were determined at 1, 3, 5, 10, 15, 20, 30, 45, 60, 90, 120, 150, 180, 210, 240, 300, and 360 min by a spectrofluorometric method. Simultaneously, neuromuscular blockade was assessed by stimulation of the ulnar nerve and quantification of thumb adductor response. Times to 50% recovery of twitch were longer in the obese than in the control patients (75 +/- 8 versus 46 +/- 8 min) as were 5%-25% recovery times (14.9 +/- 4.0 versus 10.0 +/- 1.7 min) and 25%-75% recovery times (38.4 +/- 13.8 versus 16.7 +/- 10.3 min). However, vecuronium pharmacokinetics were similar for both groups. When the data were calculated on the basis of ideal body weight (IBW) for obese and control patients, total volume of distribution (791 +/- 303 versus 919 +/- 360 mL/kg IBW), plasma clearance (4.65 +/- 0.89 versus 5.02 +/- 1.13 mL.min-1.kg IBW-1), and elimination half-life (119 +/- 43 versus 133 +/- 57 min) were not different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)
We cloned activated T cells from thyroid tissue of patients with autoimmune thyroid disease. After separation on 40% Percoll gradients, T cells were cultured for 2-7 days with T cell growth factor (interleukin 2; 20 U/mL) and cloned by limiting dilution (0.3 cells/well) in the presence of irradiated autologous peripheral blood mononuclear cells (PMC; 10,000/well) as feeder cells. Fifty-seven clones were successfully expanded and tested for reactivity, cytotoxicity, helper/suppressor function, and phenotype. In the reactivity assays clones were tested for responses to autologous and allogeneic PMC, thyroid cells, human thyroglobulin (hTg), and microsomal antigen. Two distinct patterns of functional T cell clones emerged from these characterization studies. Seventy-five percent of T cell clones recovered from Graves' disease thyroid tissue (n = 21) were of helper-induced (CD4+/4B4+) phenotype, and most were effective immunoglobulin helper clones. Fifty percent of Graves' T cell clones responded to autologous PMC, and 33% had a proliferative response to autologous thyroid cells. No cytotoxic clones were derived from Graves' thyroid tissue. By contrast, intrathyroidal T cell clones from patients with autoimmune thyroiditis (n = 36) were 59% suppressor/cytotoxic (CD8+) phenotype, 17% suppressed immunoglobulin secretion, and 55% were cytotoxic to allogeneic blast cells. Fifty-five percent of clones also responded to autologous PMC, and one clone was nonspecifically autocytotoxic. In the thyroid antigen proliferation assays 11% of thyroiditis clones reacted to human thyroglobulin, but none responded to microsomal antigen. Two clones were cytotoxic to autologous but not allogeneic thyroid cells. These data demonstrate that the majority of intrathyroidal T cells in autoimmune thyroid disease are autoreactive. However, small numbers of thyroid-specific T cell clones are present within the thyroid of such patients; they are principally helper-inducer T cells in Graves' disease thyroid and cytotoxic T cells in autoimmune thyroiditis.
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