Evidence that glutamine modulates respiratory burst in stressed rat polymorphonuclear cells through its metabolism into arginine

Glutamine (GLN) and arginine (ARG) are recognized for their ability to modulate immune cell function. However, the metabolic pathways involved in their action remain unclear. It was recently shown that GLN- or ARG-enriched diets increased radical oxygen species (ROS) production by neutrophils from stressed rats. Since these two amino acids have a tied metabolism, we hypothesized that conversion between GLN and ARG (and its active metabolites NO* and polyamines) might be involved. To test this hypothesis male Sprague-Dawley rats (n 117) were randomized into thirteen groups: rats in eleven groups were rendered catabolic by dexamethasone injection (1.5 mg/kg per d for 5 d) and 6.8 mmol either GLN, ARG or non-essential amino acids (NEAA; glycine, alanine and histidine)/kg per d were given by the enteral route; one group was pair-fed to the treated groups. The regimens of all the groups were rendered isonitrogenous by the addition of NEAA. The last group was not treated and was fed ad libitum. For each supplementation three subgroups were formed, each of which received a specific inhibitor: methionine sulfoximine (inhibitor of GLN synthase; 100 mg/kg per d), S-methylthiourea (inhibitor of inducible NO* synthase (iNOS); 50 mg/kg per d) and difluoromethylornithine (inhibitor of ornithine decarboxylase (ODC); 50 mg/kg per d). Oxidative metabolism, intracellular H2O2, and extracellular O2*- production were measured in unstimulated and phorbol myristate acetate-stimulated polymorphonuclear neutrophils. GLN- and ARG-enriched diets increased respiratory burst by neutrophils (oxidative metabolism of 152 (sem 24) and 138 (sem 45) v. 57 (sem 18) mV for GLN-, ARG- and NEAA-enriched diets respectively, P<0.05). In vivo inhibition of iNOS or ODC decreased ROS production induced by GLN and ARG. In vivo inhibition of GLN synthase did not modify the effect of ARG on ROS production. In conclusion, GLN and ARG modulate ROS production in neutrophils from stressed rats by the same pathway involving polyamine and NO* synthesis.     

Feeding Skills and Growth After One Year of Intraoral Appliance Therapy in Moderately Dysphagic Children with Cerebral Palsy

We determined changes in functional feeding skills and growth after one year of intraoral appliance therapy in dysphagic children. Twenty children, 4.2-13.1 years of age (average 8.3 +/- 0.9 years), participated in this study. Children wore the appliance daily. Phase I of treatment (6 months) aimed primarily at stabilizing the mandible and phase II aimed at facilitating ingestive skills. A control period of 6 months preceded treatment. Functional feeding skills improved significantly during phase I beyond changes seen during the control period. Further significant improvement occurred in chewing during phase II. All children significantly gained weight (kg) during the control period, as well as during the two treatment phases. This weight gain was sufficient for children to maintain their growth trajectory. There was also significant growth in height (cm). This growth spurt was characterized by marginal catch-up. Jaw stabilization was a major contributor to the significant improvement in functional feeding skills. Weight gain cannot be attributed to intervention because it occurred during the control period and was the same in magnitude through both treatment phases. However, it permitted a period of growth in stature which previously had been described only after tube feeding.     

Causes of syncope in patients with Alzheimer's disease treated with donepezil

INTRODUCTION: Treatment of Alzheimer's disease (AD) with cholinesterase inhibitors carries a theoretical risk of precipitating bradycardia. Though syncope occurs in patients with AD, its aetiology is unclear. The aim of this study was to determine the causes of syncope in patients with AD who were treated with donepezil and hospitalised for evaluation of syncope. METHODS: We studied 16 consecutive patients (12 women, 4 men) with AD aged 80 +/- 4 years who were hospitalised for evaluation of syncope. All patients underwent staged evaluation, ranging from physical examination to electrophysiological testing. RESULTS: The mean dose of donepezil administered was 7.8 mg/day, and the mean duration of donepezil treatment at the time of syncope was 12 +/- 8 months. A cause of syncope was identified in 69% of patients. Carotid sinus syndrome was observed in three patients, complete atrioventricular block in two patients, sinus node dysfunction in two patients, severe orthostatic hypotension in two patients and paroxysmal atrial fibrillation in one patient. A brain tumour was discovered in one patient. No cause of syncope was found in 31% of patients despite comprehensive investigation. Repetition of the investigations after discontinuation of donepezil was noncontributory. CONCLUSION: In patients with AD treated with donepezil, a noninvasive evaluation identified a probable cause of syncope in over two-thirds of patients. Cardiovascular abnormalities were predominant. Noninvasive evaluation is recommended before discontinuing treatment with cholinesterase inhibitors in patients with AD and unexplained syncope.     

Treatment of infrarenal aortic aneurysm by minimally invasive retroperitoneal approach: use of a video-assisted technique

We propose a technique for treating abdominal aortic aneurysm in which first a minilaparotomy (retroperitoneal) is performed to make a conventional arterial dissection; then, video assistance is used to control the left lumbar arteries and to make the aortic anastomosis. This technique can be performed with no significant laparoscopic capability.The patient was installed in a 20-degree right lateral decubitus. A transverse left 8- to 10-cm abdominal incision was made, followed by separation of the muscular structures. Retroperitoneal control of the proximal aortic neck and of both common iliac arteries was obtained by digital and instrumental dissection. A 30-degree laparoscope was then introduced through a 8- to 12-mm trocar and provided the light and magnification that facilitated the dissection of the posterior wall of the aortic neck and of the left flank of the aneurysm, looking for the lumbar arteries to be clipped. A suspended running suture to make the aorto-prosthetic anastomosis was facilitated by the magnification of the camera, especially during the passage of needles. Between March and September 2001, 32 patients fulfilled the anatomic conditions: an infrarenal aortic neck length of 2 cm or more, absence of hypogastric artery aneurysm, and no need for inferior mesenteric artery reimplantation. In 30 patients, the surgery was performed by using the planned minimally invasive approach, and extension of the incision was necessary in two patients.     

Evidence for growth-promoting effects of omega n - 3 fatty acids alone and in combination with a specific vitamin and mineral complex in rat neuroblastoma cells

The beneficial effects of Omega n - 3 polyunsaturated fatty acids (n - 3 PUFA) in situations of cognitive impairment may be associated with enhanced neuronal growth. Since neuronal growth is impaired in n - 3 PUFA deficiency, and enhanced by certain vitamins and trace elements, the effects of n - 3 PUFA, vitamin and mineral cell complex (VMC) and their association on neuronal growth were investigated in cultured rat neuroblastoma cells. Treatment of cells for 3 days with n - 3 PUFA significantly enhanced neurite length without affecting the number of neurites or cells. VMC significantly increased cell number without affecting neurite length or their number. Combined n - 3 PUFA and VMC significantly enhanced all three growth parameters. The data confirm the growth promoting effects of n - 3 PUFA and VMC in cultured neurons over a relatively short time frame.     

Modulation of nitric oxide and cytokines production by L-arginine in human gut mucosa

BACKGROUND: Arginine is a conditionally essential amino-acid with immuno-modulatory properties, mainly through the nitric oxide (NO) pathway. AIM: To assess the effects of arginine on intestinal production of pro- and anti-inflammatory cytokines and NO in human gut. METHODS: An enteral solution of arginine or a control solution of amino-acids was administered to 8 healthy volunteers on a randomized cross-over design. Duodenal biopsies were taken. Pro- (IL-6, IL-8) and anti-inflammatory (IL-4, IL-10) cytokines mRNA expression was assessed by RT-PCR. Other biopsies were cultured with 0.1, 0.5 or 2 mM arginine or control amino-acids, under basal or IL-1beta-induced inflammatory conditions. Interleukin-4, IL-6, IL-8 and IL-10 production was measured in culture supernatant by ELISA and NO production by Griess reaction. RESULTS: Arginine enhanced the production of NO under inflammatory conditions in a dose-dependent manner (P=0.03). IL-1beta increased the production of IL-8 and IL-6 (P<0.01). Arginine had no effect on pro- and anti-inflammatory cytokines production both under basal and inflammatory conditions. CONCLUSIONS: Arginine enhanced the production of NO but did not affect that of cytokines in inflammatory human gut. Further clinical studies are required to assess whether arginine-enhanced NO production plays a beneficial or deleterious effect in intestinal inflammation.