Glucocorticoid effects on the inflammatory and clinical responses to cardiac surgery

OBJECTIVE: To measure the effects of glucocorticoids on the systemic inflammatory response and clinical recovery after cardiac surgery. DESIGN: Randomized, prospective, double-blind, placebo-controlled clinical trial with concurrent comparison groups. SETTING: University medical center. PARTICIPANTS: Patients scheduled for elective coronary artery bypass graft surgery using normothermic cardiopulmonary bypass (CPB) and a standardized anesthetic. INTERVENTIONS: Participants randomly received either methylprednisolone, 15 mg/kg intravenously 1 hour before surgery and 0.3 mg/kg intravenously every 6 hours x 4 doses, or placebo. Comparison groups included cardiac surgical patients who received etomidate to lower endogenous cortisol during surgery and healthy volunteers who received methylprednisolone only. MEASUREMENTS AND MAIN RESULTS: Patients who received methylprednisolone had a significant reduction in circulating interleukin (IL)-6 at 60 minutes after CPB (p < 0.05) and on the morning of the 1st (p < 0.01) and 3rd (p < 0.05) postoperative days and a significant increase in circulating IL-10 at 60 minutes after CPB (p < 0.01) compared with the placebo group. Etomidate, given to lower cortisol during surgery, was associated with significantly decreased IL-6 and IL-10 responses to surgery compared with the placebo group, whereas methylprednisolone alone, given to healthy nonsurgical volunteers, had no effect on these cytokines. After adjusting for age, there were no significant differences in postoperative length of hospital stay between the methylprednisolone-treated (4.6 days) and placebo (6.1 days) groups or in the duration of mechanical ventilation (9.9 hours and 15.6 hours). No patient treated with methylprednisolone had nausea and vomiting on the 1st postoperative day compared with 33% of placebo-treated patients (p = 0.02). Glucose was significantly higher after methylprednisolone treatment at 1 hour after CPB (276 mg/dL v 210 mg/dL; p = 0.001) and at 2 hours (289 mg/dL v 213 mg/dL; p = 0.009) and 8 hours (247 mg/dL v 196 mg/dL; p = 0.02) after surgery. There were no differences in pain scores and no significant intergroup differences in lung peak expiratory flow rate or alveolar-arterial oxygen gradients after surgery. CONCLUSION: This study shows significant effects of glucocorticoids on the production of IL-6 and IL-10 in response to cardiac surgery but only minor effects on clinical recovery.     

Nerve injury proximal or distal to the DRG induces similar spinal glial activation and selective cytokine expression but differential behavioral responses to pharmacologic treatment

The specific mechanisms by which nervous system injury becomes a chronic pain state remain undetermined. Historically, it has been believed that injuries proximal or distal to the dorsal root ganglion (DRG) produce distinct pathologies that manifest in different severity of symptoms. This study investigated the role of injury site relative to the DRG in (1) eliciting behavioral responses, (2) inducing spinal neuroimmune activation, and (3) responding to pharmacologic interventions. Rats received either an L5 spinal nerve transection distal to the DRG or an L5 nerve root injury proximal to the DRG. Comparative studies assessed behavioral nociceptive responses, spinal cytokine mRNA and protein expression, and glial activation after injury. In separate studies, intrathecal pharmacologic interventions by using selective cytokine antagonists (interleukin-1 [IL-1] receptor antagonist and soluble tumor necrosis factor [TNF] receptor) and a global immunosuppressant (leflunomide) were performed to determine their relative effectiveness in these injury paradigms. Behavioral responses assessed by mechanical allodynia and thermal hyperalgesia were almost identical in the two models of persistent pain, suggesting that behavioral testing may not be a sensitive measure of injury. Spinal IL-1beta, IL-6, IL-10, and TNF mRNA and IL-6 protein were significantly elevated in both injuries. The overall magnitude of expression and temporal patterns were similar in both models of injury. The degree of microglial and astrocytic activation in the L5 spinal cord was also similar for both injuries. In contrast, the pharmacologic treatments were more effective in alleviating mechanical allodynia for peripheral nerve injury than nerve root injury, suggesting that nerve root injury elicits a more robust, centrally mediated response than peripheral nerve injury. Overall, these data implicate alternate nociceptive mechanisms in these anatomically different injuries that are not distinguished by behavioral testing or the neuroimmune markers used in this study.     

The in vivo effects of general and epidural anesthesia on human immune function

Impaired in vivo immunity is often observed after major surgery and is multifactorial. We conducted a randomized clinical study to determine the independent effects of general anesthesia (GA) and of lumbar epidural anesthesia (LEA) on human immune function in the absence of surgical trauma. Nineteen healthy volunteers were randomized to receive GA with thiopental and isoflurane, LEA with lidocaine, or no anesthesia (Control). Serial blood samples were tested for antibody responses to antigen inoculation, neutrophil and mononuclear cell antibody-dependent cell cytotoxicity (ADCC), natural killer cell cytotoxicity, and neutrophil phagocytic activity. Antibody responses were similar in the three groups. Mononuclear cell ADCC increased in the LEA group at the end of the anesthetic (P < 0.05 at effector/target [E/T] ratios of 10:1, 25:1, and 50:1). Natural killer cell cytotoxicity increased at the end of the anesthetic in both the LEA group (P < 0.05 at all E/T ratios) and the GA group (P < 0.05 at an E/T ratio of 5:1 and 10:1). No significant changes were observed for neutrophil ADCC or phagocytosis. General or epidural anesthesia alone, in the absence of surgery, seems to have only transient and minor effects on human immune function. IMPLICATIONS: General or epidural anesthesia alone, in the absence of surgery, seems to have only transient and minor effects on human immune function.     

Persistent hyperinsulinemic hypoglycemia of infancy: case report

OBJECTIVE: To report a case of Persistent Hyperinsulinemic Hypoglycemia in twins which is a situation not yet reported in the literature. METHODS: Report of seizures in identical twins, from consanguineous parents, with persistent hypoglycemia as cause of the seizures. Laboratory tests, performed for etiological investigation of the hypoglycemia, included thyroid hormones (T4/TSH), insulin, cortisol, growth hormone, stimulation test with glucagon (to evaluate the insulin/glucose relation), and histopathological study of the pancreas. RESULTS: Laboratorial investigation revealed a persistent hypoglycemia with hyperinsulinism which were confirmed with the stimulation test with glucagon. The histopathological exam showed a persistence of first generation pancreatic islet, confirming the diagnosis of Persistent Hyperinsulinemic Hypoglycemia in Infancy (the new denomination of Nesidioblastosis). CONCLUSION: Although rare, this condition must be early suspected early in the evaluation of hypoglycemia of the young infant, even out of the neonatal period, specially if the parents are consanguineous. The adequate therapy must be quickly initiated in order to prevent neurological damage.     

Myelin thickenings in val 102/fs null mutation of MPZ gene

Painful sensory neuropathies consist of a wide range of neuropathies that can involve large as well as small nerve fibres. Even if most cases remain of unknown cause, some of them may be associated with an underlying disorder such as diabetes, HIV, infections, amyloidosis, and Sjogren's syndrome. Since in some cases an autoimmune mechanism has been postulated, we investigated a panel of circulating autoantibodies including anti‐gliadin (AGA), anti‐endomysium (EmA), anti‐transglutaminase (tTGA) and anti‐nuclear (ANA) antibodies in the sera of patients with unexplained painful sensory neuropathies in order to identify other potentially treatable disorders. We tested the sera of 10 patients (4M; 6F) previously investigated for other causes of neuropathies, including anti‐nerve, onconeural, anti‐extractable nuclear, anti‐neutrophil cytoplasmic, anti‐thyroglobulin (TgA) and anti‐peroxidase (TPOA) antibodies. We found the presence of AGA positivity in 4 patients (40%), ANA in 7 (70%) and AGA + ANA in 4 (40%), two of whom were negative for celiac disease by gastrointestinal biopsy. None of the patients had EmA positivity. Three (30%) had TgA and TPOA and none had anti‐nerve or onconeural antibodies. Whether the presence of circulating autoantibodies in patients with unexplained painful neuropathy reflects an autoimmune involvement which may be amenable to immune therapy and not only to symptomatic treatment remains to be established.     

Cytochrome p450 polymorphisms in geriatric patients: impact on adverse drug reactions--a pilot study

BACKGROUND AND OBJECTIVE: Up to 23% of the population, depending on their ethnic background, has genetically determined differences in the metabolism of drugs by the cytochrome P450 (CYP) enzymes CYP2C9, CYP2C19 and CYP2D6. The aim of this survey was to determine the relationship between genetical polymorphisms in these CYP enzymes and adverse drug reactions (ADRs) in geriatric patients. STUDY DESIGN: In a prospective 6-month cohort study of 243 patients in a geriatric rehabilitation ward, mean age 80.2 +/- 7.7 years, ADRs were identified by intensive monitoring by a pharmacoepidemiological team, consisting of pharmacists and physicians. 125 out of these 243 patients were genotyped cross-sectionally for polymorphisms of CYP2C9, CYP2C19 and CYP2D6 by the TaqMan-polymerase chain reaction. The main outcome measures were the prevalence of genetical polymorphisms and the patients' risk for developing an ADR as related to the genotype. RESULTS: Patients received an average of 14.2 drugs during hospitalisation which led to 251 ADRs in the whole cohort and 149 ADRs in the cross-sectional genotyping study. Genotype frequencies of CYP2C9 enzyme were 25.9% (n = 29) intermediate metabolisers (IMs) and 2.7% (n = 3) poor metabolisers (PMs). For the enzyme CYP2C19, 26.8% (n = 33) IMs and 0.8% (n = 1) PMs were detected. For the enzyme CYP2D6, 24.1% (n = 26) IMs and 3.7% (n = 4) PMs were found in the analysed patient population. In total, 61.6% (n = 77) of genotyped patients experienced mutations in at least one of the three cytochrome enzymes. The ADR rate did not differ significantly between patients with genetic mutations and wild-type genotype patients. Moreover, only eight out of 40 ADRs which were associated with drugs metabolised by CYP2C9, CYP2C19 or CYP2D6 were detected in patients with IM genotype and none in patients with PM genotype. CONCLUSION: In this investigation geriatric patients showed a high rate of ADRs. However, no association between the ADR rate and the patients' genotype could be detected, which most likely was a result of the small number of patient samples analysed.Although prophylactic genotyping would have not prevented ADRs in this pilot study, physicians nevertheless have to be aware of potential genetic mutations in patients with polypharmacy.     

A bronchogenic cyst of the right ventricular endocardium

In a 73-year-old male patient with a history of prostate cancer, a right ventricular endoluminal tumor was diagnosed by echocardiography. An endocardial papillary fibroelastoma or myxoma appeared possible; a malignant tumor could not be ruled out. The tumor was resected using extracorporeal circulation and cardioplegic arrest. Histopathology study revealed a bronchogenic cyst with ciliated epithelium.     

Visualizing reaction pathways in photoactive yellow protein from nanoseconds to seconds

Determining 3D intermediate structures during the biological action of proteins in real time under ambient conditions is essential for understanding how proteins function. Here we use time-resolved Laue crystallography to extract short-lived intermediate structures and thereby unveil signal transduction in the blue light photoreceptor photoactive yellow protein (PYP) from Halorhodospira halophila. By analyzing a comprehensive set of Laue data during the PYP photocycle (forty-seven time points from one nanosecond to one second), we track all atoms in PYP during its photocycle and directly observe how absorption of a blue light photon by its p-coumaric acid chromophore triggers a reversible photocycle. We identify a complex chemical mechanism characterized by five distinct structural intermediates. Structural changes at the chromophore in the early, red-shifted intermediates are transduced to the exterior of the protein in the late, blue-shifted intermediates through an initial "volume-conserving" isomerization of the chromophore and the progressive disruption of hydrogen bonds between the chromophore and its surrounding binding pocket. These results yield a comprehensive view of the PYP photocycle when seen in the light of previous biophysical studies on the system.