Ankylosing spondylitis antirheumatic drug trials. III. Setting the delta for clinical trials of antirheumatic drugs--results of a consensus development (Delphi) exercise.

Defining the minimum clinically important difference or delta to be detected in a clinical trial depends on a number of factors including the research hypothesis, patient characteristics, the nature of the intervention and the trial design. In 2 previous studies, we have developed standardized procedures for conducting outcome measurement based on current Food and Drug Administration and European League Against Rheumatism guidelines for clinical trials in ankylosing spondylitis, and thereafter, determined the standard deviation for these outcome measures. In the final component of this series of studies, we have employed a Delphi technique to establish estimates for delta, and calculated the sample size requirements under 2 different conditions of Type I and Type II error probabilities.     

A study of 100 high risk lupus pregnancies.

Certain subgroups of lupus patients and those with circulating antiphospholipid antibodies (aPL) in particular, suffer a high rate of fetal loss. Over the past 4 years, we have prospectively studied 100 pregnancies in patients with systemic lupus erythematosus (SLE) and primary antiphospholipid syndrome. In addition to conventional methods of monitoring SLE and fetal development, we have also used Doppler flow assessment of placental perfusion from the 14th wk of pregnancy onward. Patients with the antiphospholipid syndrome and previous history of thrombotic events were treated with daily heparin (10,000 IU) and low-dose aspirin (75 mg). Those without a history of thrombosis were treated with low-dose prednisolone, azathioprine, or hydroxychloroquine. Pregnancy loss was reduced from 81.3% in 101 previous pregnancies to 36.8% in 100 pregnancies managed by us. None of the patients who received hydroxychloroquine throughout the pregnancy presented fetal malformations. Careful management and close monitoring of the lupus pregnancy has substantially improved fetal outcome.     

Factors affecting patency of internal thoracic artery graft: clinical and angiographic study in 1434 symptomatic patients operated between 1982 and 2002.

OBJECTIVE: The purpose is to define factors influencing long-term patency of the internal thoracic artery (ITA) to optimize the operative strategy. METHODS: 1482 left internal thoracic artery (LITA) and 636 right internal thoracic artery (RITA) symptom-directed angiograms were studied in 1434 patients. Data were prospectively collected from patients who had primary coronary artery bypass surgery during the period 1982-2002. The mean age of patients was 59 years; 85% were male. The mean period from operation to re-angiogram was 80 months. LITA was grafted to left anterior descending coronary artery (LAD) in 82% of cases, RITA to right coronary artery (RCA) in 40% and circumflex artery in 35% of cases. Graft failure was defined as > or =80% stenosis. RESULTS: 96.3% of LITA and 88.1% of RITA grafts were patent. No patient variables were significantly associated with graft patency (age, gender, diabetes, hypertension, LVEF, NYHA, AMI). Target coronary artery was associated with patency of both LITA and RITA grafts with maximum patency when grafted to LAD (P = 0.02) RITA had the worst patency to RCA, patency for the left system was identical to LITA. Proximal anastomosis to aorta (free RITA) had significantly better patency when compared with in situ RITA to RCA system (P = 0.005) while similar patency when grafted to left system. ITA diameter and target artery diameter were not associated with graft patency. Recent operations had better RITA patency (P = 0.03). The interval from operation to angiogram was not associated with ITA patency (96% patency for LITA and 88% patency for RITA, remained stable when studied at <1, 1-4, 5-9, 10-14 and >15 years). CONCLUSIONS: Even in a patient cohort that had adverse symptoms, excellent LITA and RITA patency was achieved which almost remained constant through all time intervals studied.     

Review article: The role of anticonvulsant drugs in postoperative pain management: a bench-to-bedside perspective

PURPOSE: Anticonvulsant drugs are effective in the treatment of chronic neuropathic pain but were not, until recently, thought to be useful in more acute conditions such as postoperative pain. However, similar to nerve injury, surgical tissue injury is known to produce neuroplastic changes leading to spinal sensitization and the expression of stimulus-evoked hyperalgesia and allodynia. Pharmacological effects of anticonvulsant drugs which may be important in the modulation of these postoperative neural changes include suppression of sodium channel, calcium channel and glutamate receptor activity at peripheral, spinal and supraspinal sites. The purpose of this article is to review preclinical evidence and clinical trial data describing the efficacy and safety of anticonvulsant drugs in the setting of postoperative pain management. SOURCE: A Medline search was performed to retrieve available literature on the basic and clinical pharmacology of anticonvulsant drugs as they pertain to postoperative pain management. PRINCIPAL FINDINGS: Numerous laboratory studies have described analgesic effects of different anticonvulsant drugs in experimental pain models. Furthermore, several recent clinical trials have shown that anticonvulsants may reduce spontaneous and movement-evoked pain, as well as decrease opioid requirements postoperatively. Some early findings suggest further that anticonvulsant drugs may alleviate postoperative anxiety, accelerate postoperative functional recovery and reduce chronic postsurgical pain. CONCLUSION: Given the incomplete efficacy of currently available non-opioid analgesics, and the identified benefits of opioid sparing, anticonvulsant medications may be useful adjuncts for postoperative analgesia. Further research in this field is warranted.     

Supply and demand in cerebral energy metabolism: the role of nutrient transporters.

Glucose is the obligate energetic fuel for the mammalian brain, and most studies of cerebral energy metabolism assume that the majority of cerebral glucose utilization fuels neuronal activity via oxidative metabolism, both in the basal and activated state. Glucose transporter (GLUT) proteins deliver glucose from the circulation to the brain: GLUT1 in the microvascular endothelial cells of the blood-brain barrier (BBB) and glia; GLUT3 in neurons. Lactate, the glycolytic product of glucose metabolism, is transported into and out of neural cells by the monocarboxylate transporters (MCT): MCT1 in the BBB and astrocytes and MCT2 in neurons. The proposal of the astrocyte-neuron lactate shuttle hypothesis suggested that astrocytes play the primary role in cerebral glucose utilization and generate lactate for neuronal energetics, especially during activation. Since the identification of the GLUTs and MCTs in brain, much has been learned about their transport properties, that is capacity and affinity for substrate, which must be considered in any model of cerebral glucose uptake and utilization. Using concentrations and kinetic parameters of GLUT1 and -3 in BBB endothelial cells, astrocytes, and neurons, along with the corresponding kinetic properties of the MCTs, we have successfully modeled brain glucose and lactate levels as well as lactate transients in response to neuronal stimulation. Simulations based on these parameters suggest that glucose readily diffuses through the basal lamina and interstitium to neurons, which are primarily responsible for glucose uptake, metabolism, and the generation of the lactate transients observed on neuronal activation.     

Cognitive rehabilitation in the elderly: overview and future directions.

This study provides an overview of the papers emanating from the experimental trial that evaluated a new cognitive rehabilitation program in older adults who were experiencing normal cognitive decline. The main features of the design are summarized, along with evidence that the training produced long-lasting improvement in memory performance, goal management, and psychosocial status. The benefits were attributed to several factors, including the program's emphasis on techniques that promoted efficient strategic processing. Limitations of the program and directions for future research are discussed.