Biomedical subjects
Publications and source records attributed to C Lambert.
A case of a child with Becker's muscular dystrophy is presented. Because of the genetic and clinical similarity with the more common Duchenne muscular dystrophy, these two diseases are compared. Since muscular dystrophy often initially presents with toe walking, flat-foot, and waddling gait, podiatrists may be the first physicians to see the child and provide early diagnosis.
TNF is clearly involved in allograft rejection but measurement of serum cytokine levels do not reflect reliably the rejection crisis. TNF induces release of soluble receptor parts that are more stable, are catabolized by kidneys and have inhibitory activity. Thus it is crucial to analyse their kinetics during renal function recovery after transplantation to forecast their potential clinical use in rejection monitoring or treatment. A sequential study was performed in 61 patients undergoing kidney graft, compared to 60 graft patients with long follow-up and 15 healthy controls. Soluble TNF and Il2 receptors were measured by ELISA and TNF was measured by RIA. The sTNF-Rs were markedly increased in renal failure, much more than another soluble cytokine receptor, the sIl2-R. Levels progressively decreased with the recovery of renal function and became directly correlated to the renal function. Normal levels were only reached after some weeks. No significant changes were observed during graft rejection at that stage of renal function but p75 were higher after antilympocyte antiserum and tubular necrosis. High sTNF-R did not seem to minimize rejection risk or gravity. In long-standing recipients, sTNF-R rose in some patients, particularly with glomerulonephritis, and may help in monitoring chronic rejection activity. sTNF-R but not sIl2-R markedly accumulate in ESRF and mask any changes that could be helpful in the monitoring of early graft events. However, increased levels above renal impairment (sTNF-R/SCr) may be clinically relevant in late rejection or glomerulonephritides.
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The effects of procainamide and propafenone on the composition of the excitable gap (EG) were studied in a canine model of atrial flutter (AFI) around the tricuspid valve. In 14 open-chest, chloralose-anesthetized dogs, a Y-shaped incision was made in the intercaval area extending to the right atrial appendage. Atrial effective refractory period (ERP) was measured at constant stimulation cycle lengths (CLs) (200 and 300 msec) at each of five recording sites around the tricuspid valve. The EG as defined by the reset-response curve was determined by introducing premature stimuli during AFI induced by burstpacing. Seven dogs each received procainamide or propafenone as a bolus followed by infusion. At constant plasma levels, both drugs increased ERP at constant paced CL and prolonged the reentry CL. In the absence of drug, reset-response curves were mixed, demonstrating an EG composed of both partially (increasing portion) and fully (flat portion) excitable tissue. Procainamide and propafenone shifted the curve upward and to the right and prolonged ERP during AFI, but did not change the duration of the EG. On procainamide, fully excitable tissue was preserved, but on propafenone, in some cases, the fully excitable part of the gap was reduced markedly or even eliminated. In conclusion, both drugs can prolong AFI CL by a direct effect on conduction velocity in fully excitable tissue. In addition, propafenone's effect on refractoriness can contribute significantly in some cases to slowing of AFI.
Cardizem SR and Bi-Tildiem were both approved in their respective countries on the basis of clinical trials demonstrating efficacy and safety in the treatment of angina pectoris. In this cross-over randomized study, we assessed whether these two sustained-release formulations of diltiazem have equivalent pharmacokinetic and pharmacodynamic profiles. Twenty-four young healthy male volunteers were hooked to Holters and ambulatory blood pressure monitors for 24 h to establish baseline systolic blood pressure (SBP), diastolic blood pressure (DBP), sinus rate and PR intervals. They then received a single dose of 120 mg of diltiazem from one formulation. The pharmacodynamic measurements were recorded for a further 24 h and blood samples were collected over 36 h for evaluation of diltiazem in plasma by a high-performance liquid chromatogrpahic (HPLC) method. The procedures were repeated with the alternate formulation after a 7 d wash-out. Pharmacokinetics showed statistically significant (p < 0.01) differences in AUC0-12 with means (+/- SD) of 519.2(+/- 172.8) and 429.6(+/- 147.2) ng h ml-1, AUC0-36 of 835.6(+/- 281.6) and 730.9 (+/- 271.5) ng h ml-1 and Cmax of 89.1(+/- 30.3) and 61.1(+/- 21.2) ng ml-1 for Cardizem SR and Bi-Tildiem, respectively. The only pharmacodynamic parameter showing a statistically significant difference in change from baseline between the two formulations was DBP with mean (+/- SD) change in AUC0-12 of -13.6(+/- 20.8) and +8.4(+/- 31.7) mm Hg h (p = 0.0135) and in AUC0-24 of -33.0(+/- 43.7) and -0.3(+/- 59.2) mm Hg h (p = 0.0463) for Cardizem SR and Bi-Tildiem, respectively. These findings suggest that assessment of efficacy of sustained-release formulations of diltiazem by bioequivalence could be misleading. They also confirm that a single dose of diltiazem does not elicit a significant pharmacodynamic response in healthy volunteers. Equivalence for such formulations should therefore be demonstrated by pharmacodynamic evaluation or clinical studies in a patient population.
Although sociology plays an increasingly important role in nurse education, many nurse learners are unable to assimilate sociological knowledge in relation to nursing practice. The relevance of sociology and its contribution to nursing is questioned and its usefulness is lost in a self-imposed web of confusion. Using the allegory of Plato's cave, I suggest that the root of the problem lies in the epistemology of nursing and the manner in which the culture of nursing is reproduced. From this premise, the use of seminar learning to dismantle the web will be discussed in this paper.
We studied the effects of modafinil, a putative central alpha-1 agonist, on the excessive daytime sleepiness (EDS) of 10 narcoleptic patients while using a double-blind design and objective measurements of vigilance. There were two treatment periods, in which either modafinil or placebo was used; each lasted four weeks and was preceded by a 2-week "run-in" period and separated by a 2-week "wash-out" period. The effects of treatment on EDS were evaluated by daily home questionnaires and a psychomotor performance test, the Four Choice Reaction Time Test (FCRTT). Modafinil reduced the daily number of sleep attacks significantly, and markedly improved performances during the FCRTT. Results of this study suggest that modafinil is effective in treating EDS in narcolepsy, and that noradrenergic mechanisms could be involved in the physiopathology of EDS in that disorder.
Bromocriptine, a preferential D2 receptor agonist, was administered to six human narcoleptic patients during a double-blind, cross-over study. Laboratory sessions consisted of two all-night polysomnographic recordings and three daytime tests of vigilance: the Analogue Vigilance Scale (AVS), the Maintenance of Wakefulness Test (MWT), and the Four-Choice Reaction Time Test (FCRTT). No change in nocturnal sleep organization, daytime somnolence, or psychomotor performance was observed during bromocriptine administration. Periodic limb movements in sleep (PLMS) were significantly reduced during bromocriptine condition. These results suggest that D2 receptors are unlikely to play a major role in the physiopathology of human narcolepsy, and support the hypothesis that dopaminergic mechanisms are involved in PLMS.
Ten volunteers received piperacillin (4 g), piperacillin (4 g) plus tazobactam (0.5 g) (Tazocin), and ticarcillin (3 g) plus clavulanic acid (0.2 g) (Timentin) intravenously over 30 min in a cross-over blinded scheme. Blood samples were obtained 0.5 and 3 h after the end of infusion to measure by (high-pressure liquid chromatography) the concentration and bactericidal titers against 70 gram-negative bacilli. Serum time-kill curves were done against 35 strains to measure killing rates and area under the time-kill curve. Using the measure of serum bactericidal activity, ticarcillin-clavulanic acid and piperacillin-tazobactam were equally effective against Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Serratia marcescens, and Bacteroides fragilis. Piperacillin-tazobactam was superior to ticarcillin-clavulanic acid against piperacillin-resistant Klebsiella pneumoniae (4 to 16 times) and S. marcescens (2 to 4 times). By using the area under the time-kill curve, piperacillin-tazobactam was equivalent to ticarcillin-clavulanic acid against piperacillin-susceptible strains; piperacillin-tazobactam was significantly more active than piperacillin against piperacillin-resistant strains and was more active than ticarcillin-clavulanic acid when the sample obtained 3 h after the end of infusion to volunteers was considered. Serum piperacillin concentrations (mean +/- standard error of the mean; in mg/liter) were 115 +/- 13 at 0.5 h and 7.4 +/- 1.4 at 3 h after the administration of piperacillin alone and 105.5 +/- 12.6 (0.5 h) and 7.7 +/- 1.6 after the administration of piperacillin-tazobactam. Serum tazobactam concentrations (in milligram per liter) were 13.1 +/- 1.4 at 0.5 h and 1.2 +/- 0.2 at 3 h. The piperacillin-tazobactam ratio was 8 +/- 0.3 at 0.5 h and 6.2 +/- 0.5 at 3 h. Piperacillin-tazobactam appears promising against beta-lactamase-producing gram-negative bacilli.
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This study examined the relationships of role stress and psychological hardiness and identified predictors of role stress in nurse educators overall and in those either involved or not involved in faculty practice. In addition, the study examined differences in psychological hardiness and role stress between nurse educators either involved or not involved in faculty practice. Data were obtained through three mailed self-report questionnaires from 871 nurse educators employed full-time in a National League for Nursing (NLN)-accredited school of nursing with both undergraduate and graduate programs. The findings revealed significant negative correlations between role stress and psychological hardiness and between components of role stress and components of psychological hardiness. Predictors of role stress were identified. No significant difference was found in role stress or in psychological hardiness between nurse educators involved and those not involved in faculty practice.
The influence of cimetidine on the natriuretic and diuretic responses to furosemide was studied in 10 patients with hepatic cirrhosis. After four days on a low sodium diet, the patients were given 40 mg of furosemide i.v. and from the sixth to the eleventh day they received 400 mg of cimetidine p.o. every 6 h and a second dose of furosemide with the last 6 h dose. Ten healthy subjects received the same dose of furosemide. Multiple blood and urine samples from both groups were analyzed for furosemide, sodium and creatinine. Furosemide kinetics were not affected in patients with hepatic cirrhosis but the effect was lower than in the controls: urinary excretion of sodium (0.47 +/- 0.07 vs 1.59 +/- 0.10 mmol/min, p < 0.05) and urine excretion (4.86 +/- 0.57 vs 9.16 +/- 0.85 ml/min, p < 0.05). The predicted maximal effect of furosemide (Emax) and the furosemide urinary rate of excretion needed to elicit 50% of Emax for the cirrhotic patients and the controls were 1.85 +/- 0.21 and 3.22 +/- 0.41 mmol/min (p < 0.05) and 137 +/- 15 and 99 +/- 12 micrograms/min (p < 0.05), respectively. The amounts of sodium filtered (FNa) and reabsorbed in response to the injection of furosemide were lower in the cirrhotic patients than in the controls, however, relative to the FNa, the cirrhotic patients reabsorbed more sodium than the controls. The administration of cimetidine did not affect the kinetics of furosemide nor its natriuretic or diuretic responses.(ABSTRACT TRUNCATED AT 250 WORDS)
Tamm-Horsfall protein (THP) is the major glycoprotein component of urine, yet its biological role remains obscure. Recent reports have suggested that a concanavalin A (Con A)-binding fraction of THP from pregnancy urine can bind the cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1). In order to investigate this claim in relation to THP from normal adult urine we raised monoclonal antibodies to THP and sought THP/TNF-alpha interactions in three separate assay systems. We found no evidence that THP binds to TNF-alpha under physiological conditions, but we observed that it exerts a weak, probably not physiologically relevant, but reproducible inhibitory effect on the toxicity of TNF-alpha for monolayers of L929 cells, even when the cells are pretreated with the THP, and washed before addition of the cytokine. Since our preparations of THP do not interact directly with TNF-alpha we postulated an interaction with the cells themselves, or with their extracellular matrix. The THP was found by ELISA, immunoblotting and immunohistology, to bind to as yet unidentified components of the extracellular matrix in a manner dependent on cations, pH and carbohydrates. These data, considered in the light of the published amino acid sequence and biochemical properties, suggest that THP is a member of a structural glycoprotein family known to modulate cell adhesion.
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OBJECTIVE: To assess the claim that the human 60-kd heat-shock protein (HSP) is highly expressed in the joints of patients with rheumatoid arthritis (RA), but is not readily detected in normal tissues. METHODS: Monoclonal antibodies were raised against the human 60-kd mitochondrial heat-shock protein (P1 protein; hsp60), and their specificity was established. They were then applied to synovial tissue. RESULTS: HSP was expressed similarly in normal, osteoarthritic, and RA synovium. Low levels of hsp60 were detected in synovial fluid by immunoprecipitation. CONCLUSION: Minor differences in the distribution of hsp60 in synovium from RA joints were attributable to increased cellularity and to the disorganization of the tissue architecture.
Clentiazem, 8-chloro diltiazem, is a calcium channel blocker currently undergoing evaluation for the treatment of stable angina and hypertension. As patients with ischaemic disorders often present some degree of heart failure, the aim of this study was to investigate the effect of congestive heart failure on clentiazem (200 micrograms kg-1, i.v. bolus) pharmacokinetics in a canine model. Congestive heart failure was induced in six dogs by rapid ventricular pacing (240 beats min-1) for 3-5 weeks. Clentiazem pharmacokinetics was studied in each dog under the control condition and after the development of clinical signs of heart failure (ascites, dyspnea, fatigue). Blood samples were collected up to 480 min post-dose. Clentiazem plasma concentrations were determined by high performance liquid chromatography. The area under the plasma concentration versus time curves (AUC0-infinity) was significantly increased in congestive heart failure dogs (8.8 +/- 1.6 vs 21.8 +/- 1.4 micrograms min ml-1) (mean +/- SEM). These changes were related to a reduction of the volume of distribution of the central compartment (0.9 +/- 0.1 vs 0.2 +/- 0.11 kg-1) and total body clearance (1.9 +/- 0.4 vs 0.7 +/- 0.21 h-1 kg-1). It is concluded that, in our model, congestive heart failure significantly modifies clentiazem disposition. These results suggest that caution should be exercised when clentiazem is given to patients with a low ejection fraction and a compromised cardiac function. Reduced loading and maintenance doses might be recommended in patients with severe congestive heart failure.
The nitrosyl complexes pentachloronitrosylosmate(II), [OsCl5(NO)]2-, and hydroxytetranitronitrosylosmate(II), [Os(OH)(NO2)4(NO)]2-, were evaluated as parent species for use on the 191Os-191mIr generator in an attempt to increase the 191mIr yield of the generator by providing a direct route to a chemically stable 191mIr daughter. The uptake of the 191Os-labeled complexes by the inorganic ion-exchangers ZrO2, SnO2, PbS, MnO2 and Al2O3 and the organic resin AG MP-1 was measured and prototype generators were prepared using those exchangers that demonstrated greater than 90% uptake of the 191Os-labeled complexes. The 191mIr(III)-nitrosyl complexes produced subsequent to beta- decay of the 191Os-nitrosyl parent complexes were found to undergo secondary chemical reactions to form nitro (NO2-) complexes that were tightly retained on the ion exchanger limiting 191mIr yield to less than 5%.