Abnormalities in urinary pterin levels in Rett syndrome.

The pterins, neopterin and biopterin, occur naturally in body fluids including urine. Increased neopterin levels are associated with activation of the cellular immune system and reduced biopterins are essential for biosynthesis of the monoamine neurotransmitters. The present study measured urinary neopterin and biopterin by high-performance liquid chromatography in 40 subjects with Rett syndrome, eight of their healthy sisters and 29 female control volunteers (age range 2-54 years). The results confirm earlier preliminary findings that urinary neopterin levels are raised in a proportion of young girls with Rett syndrome but not in the older women. In contrast urinary biopterin levels are not different from controls in the youngest children but remain low while control values increase with age. These findings may indicate immune activation during the regression phase of Rett syndrome but also raise the possibility that an inherited fault in tetrahydrobiopterin metabolism increases the risk of developing the disorder.

Effects of isoflurane, sevoflurane and propofol anaesthesia on jugular venous oxygen saturation in patients undergoing coronary artery bypass surgery.

We investigated the effect of sevoflurane, isoflurane and propofol on jugular venous bulb oxygen saturation (SjO2) in 21 patients undergoing coronary artery bypass graft surgery (CABG) during and after normothermic cardiopulmonary bypass (CPB). Patients received a standardized anaesthetic consisting of fentanyl, midazolam and were then randomly allocated to receive either isoflurane, sevoflurane or propofol for maintenance. SjO2 values were significantly lower than baseline 1 h after CPB in the propofol but not the isoflurane or the sevoflurane groups. Furthermore, SjO2 values were significantly higher during CPB in the isoflurane group (P = 0.0081) and significantly lower 6 h after CPB in the sevoflurane group (P = 0.0447) when compared to the propofol group. We conclude that jugular venous desaturation during and after normothermic CPB is more likely during propofol anaesthesia.

Cerebrovascular cytokine responses during coronary artery bypass surgery: specific production of interleukin-8 and its attenuation by hypothermic cardiopulmonary bypass.

UNLABELLED: Brain dysfunction after cardiopulmonary bypass (CPB) is common, and it has been hypothesized that this injury might be due partly to activation of inflammatory processes in the brain. We measured juguloarterial gradients for interleukin-1beta, interleukin-6, and interleukin-8 (IL-8) as indices of local proinflammatory cytokine production in the brain and studied the effect of temperature during CPB on these changes. Twelve patients undergoing coronary artery bypass graft surgery (normothermic CPB n = 6, hypothermic CPB n = 6) were studied. Cytokine levels were measured in paired arterial and jugular bulb samples obtained before, during, and after CPB. Although systemic levels of all three cytokines increased during and after CPB, increases in juguloarterial cytokine gradients were observed only for IL-8. Juguloarterial IL-8 gradients started to increase 1 h post-CPB and were significantly elevated 6 h post-CPB (P < 0.05). At this time point, the median (interquartile range) juguloarterial IL-8 gradients were significantly larger in the normothermic CPB group (25.81 [24.49-39.51] pg/mL) compared with the hypothermic CPB group (6.69 [-0.04 to 15.47] pg/mL; P < 0.05). These data imply specific and significant IL-8 production in the cerebrovascular bed during CPB and suggest that these changes may be suppressed by hypothermia during CPB. IMPLICATIONS: Using juguloarterial gradients to measure cerebrovascular cytokine production is novel in the setting of cardiopulmonary bypass and implicates the cerebral activation of inflammatory processes, which may contribute to brain dysfunction. Hypothermia during cardiopulmonary bypass may significantly attenuate this response.

Urinary levels of neopterin and biopterin in autism.

The pterins, neopterin and biopterin, occur naturally in body fluids including urine. It is well established that increased neopterin levels are associated with activation of the cellular immune system and that reduced biopterins are essential for neurotransmitter synthesis. It has been suggested that some autistic children may be suffering from an autoimmune disorder. To investigate this further we performed high performance liquid chromatography analyses of urinary pterins in a group of pre-school autistic children, their siblings and age-matched control children. Both urinary neopterin and biopterin were raised in the autistic children compared to controls and the siblings showed intermediate values. This supports the possible involvement of cell-mediated immunity in the aetiology of autism.