Molecular characterization of the level of sialic acids N-acetylneuraminic acid, N-glycolylneuraminic acid, and ketodeoxynonulosonic acid in porcine milk during lactation.

Sialic acids (Sia) are key monosaccharide constituents of sialylated glycoproteins (Sia-GP), human sialylated milk oligosaccharide (Sia-MOS), and gangliosides. Human milk sialylated glycoconjugates (Sia-GC) are bioactive compounds known to act as prebiotics and promote neurodevelopment, immune function, and gut maturation in newborns. Only limited data are available on the Sia content of porcine milk. The objective of this study was to quantitatively determine the total level of Sia N-acetylneuraminic acid (Neu5Ac), N-glycolylneuraminic acid (Neu5Gc), and ketodeoxynonulosonic acid (KDN) in porcine milk and to compare these levels in gilt and sow milk during lactation. Milk from 8 gilts and 22 sows was collected at 3 stages of lactation (colostrum, transition, and mature milk). Standard and experimental samples were derivatized using 1,2-diamino-4,5-methylenedioxy-benzene and analyzed by ultra-high-performance liquid chromatography using a fluorescence detector. The following new findings are reported: (1) Gilt and sow milk contained significant levels of total Sia, with the highest concentration in colostrum (1,238.5 mg/L), followed by transition milk (778.3 mg/L) and mature milk (347.2 mg/L); (2) during lactation, the majority of Sia was conjugated to Sia-GP (41-46%), followed by Sia-MOS (31-42%) and a smaller proportion in gangliosides (12-28%); (3) Neu5Ac was the major form of Sia (93-96%), followed by Neu5Gc (3-6%) and then KDN (1-2%), irrespective of milk fraction or stage of lactation; (4) the concentration of Sia in Sia-GP and Sia-MOS showed a significant decline during lactation, but the level of ganglioside Sia remained relatively constant; (5) mature gilt milk contained a significantly higher concentration of Sia-GP than sow milk. The high concentration of total Sia in porcine milk suggests that Sia-GC are important nutrients that contribute to the optimization of neurodevelopment, immune function, and growth and development in piglets. These findings provide an important rationale for the inclusion of Sia-GC in pig milk replacers to mimic porcine milk composition for the optimal growth and development of piglets.

The effect of active immunization against adrenocorticotropic hormone on cortisol, beta-endorphin, vocalization, and growth in pigs.

Because the poor growth performance of intensively housed pigs is associated with increased circulating glucocorticoid concentrations, we investigated the effects of glucocorticoid suppression by inducing a humoral immune response to ACTH on physiological and production variables in growing pigs. Grower pigs (28.6 +/- 0.9 kg) were immunized with amino acids 1 through 24 of ACTH conjugated to ovalbumin and suspended in diethylaminoethyl (DEAE) dextran-adjuvant or adjuvant alone (control) on d 1, 28, and 56. The ACTH-specific antibody titers generated suppressed increases in cortisol concentrations on d 63 in response to an acute stressor (P = 0.002; control = 71 +/- 8.2 ng/mL; ACTH-immune = 43 +/- 4.9 ng/mL) without altering basal concentrations. Plasma beta-endorphin concentrations were also increased (P < 0.001) on d 63 (control = 18 +/- 2.1 ng/mL; ACTH-immune = 63 +/- 7.3 ng/mL), presumably because of a release from negative feedback on the expression of proopiomelanocortin in pituitary corticotropes. Immunization against ACTH did not alter ADG (P = 0.120; control = 1,077 +/- 25; ACTH-immune = 1,143 +/- 25 g) or ADFI (P = 0.64; control = 2,719 +/- 42; ACTH-immune = 2,749 +/- 42 g) and did not modify behavior (P = 0.681) assessed by measuring vocalization in response to acute restraint. In summary, suppression of stress-induced cortisol responses through ACTH immunization increased beta-endorphin concentrations, but it did not modify ADG, ADFI, or restraint vocalization score in growing pigs.

Spinal cord stimulation: a seven-year audit.

OBJECTIVE: To evaluate the outcome and complications of spinal cord stimulation (SCS) for chronic neuropathic pain in an Australian population. MATERIALS AND METHODS: An independent researcher retrospectively examined the records of 138 patients trialing SCS between 1995 and 2002 at our institution. Information collected included pain relief, ability to perform activities of daily living (ADLs), return to work and reduction in opiate analgesia. Clinical, psychological, demographic and financial data were also collected. RESULTS: Of 138 patients who trialed SCS, 103 (74.7%) achieved a greater than 50% reduction in their pain and proceeded to permanent implantation. At 1 year following permanent implantation, 84.4% of these still had a reduction in their pain by greater than 50%. The majority of patients, 59.1%, stated that their analgesia was good (50-74% pain reduction). All patients required opiate analgesics prior to SCS implantation, but this fell to 54.6% after SCS implantation. Additionally, 73.6% had a significant improvement in their ability to perform ADLs and 24% of patients were able to return to work. CONCLUSION: SCS is an effective treatment in the control of chronic neuropathic pain, particularly in combination with comprehensive medical management within a multidisciplinary pain management centre.

Corticotropin-releasing factor (CRF) induces desensitization of the rat pituitary CRF receptor-adenylate cyclase complex.

The rise in circulating ACTH levels after adrenalectomy in the rat is associated with a decrease in CRF receptor-binding capacity in the anterior pituitary. To investigate the role of increased hypothalamic CRF release on pituitary CRF receptor regulation after withdrawal of glucocorticoid feedback by adrenalectomy, the effects of chronic CRF infusion and lesions in the medial basal hypothalamus were studied in the rat. Subcutaneous infusion of CRF at 10, 25, 50, and 100 ng/min for 48 h in intact rats caused dose-dependent increases in plasma ACTH levels from the control value of 32.1 +/- 4.3 to 58.0 +/- 4.9, 82.0 +/- 7.1, 135.5 +/- 11.6, and 149.2 +/- 13.2 pg/ml, respectively. In contrast, the pituitary CRF receptor concentration was reduced by 25.3 +/- 4.5%, 38.3 +/- 2.5%, 43.8 +/- 0.9%, and 45.8 +/- 2.0%, respectively. Intravenous infusion of increasing doses of CRF caused a similar increase in plasma ACTH levels, which became maximum at the lowest infusion dose (32.4 +/- 5.4, 138.5 +/- 12.3, 162.0 +/- 18.3, and 167 +/- 19.1 pg/ml for control and 10, 50, and 100 ng/min CRF, respectively). Pituitary CRF receptor concentration was again decreased after iv CRF infusion [by 42 +/- 6.2% with the lowest dose (10 ng/min)], with no further reduction after infusion of 50 and 100 ng/min (49.0 +/- 6.8% and 26.0 +/- 6.2%, respectively)]. The decrease in pituitary CRF receptors after CRF infusion was accompanied by a decrease in CRF-stimulated adenylate cyclase activity, with a 10- to 100-fold increase in the concentration of CRF required for threshold stimulation. In cultured pituitary cells prepared from animals infused with 50 ng/min CRF for 48 h, maximum CRF-stimulated ACTH release was reduced by 29 +/- 3.2% (P less than 0.01; n = 3), with no significant change in sensitivity to CRF (ED50, 0.6 +/- 0.5 and 1.0 +/- 0.5 nM CRF for control and CRF infusion, respectively). The role of endogenous CRF in adrenalectomy-induced pituitary CRF receptor down-regulation was also studied in rats with medial basal hypothalamic deafferentation. The marked loss of pituitary CRF receptors after adrenalectomy was completely prevented by such hypothalamic lesioning, indicating that receptor down-regulation was dependent on the release of CRF or/and other hypothalamic factors. The data demonstrate that while increased CRF levels result in down-regulation and desensitization of pituitary CRF receptors, the differences between adrenalectomy and CRF infusion indicate that additional regulatory factors are involved in the modulation of CRF receptor content and activity after adrenalectomy.

Clinical studies on the phenylethylamine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplements.

To test the hypothesis that 2-phenylethylamine (PEA) modulates affect, plasma levels and urinary excretion of its main metabolite, phenylacetic acid (PAA), were studied in depressed and manic subjects, and the mood-elevating effects of its precursor, L-phenylalanine, were studied in depressed subjects. Mean total plasma PAA concentrations were 491.83 +/- 232.84 ng/ml in 12 healthy volunteers and 300.33 +/- 197.44 ng/ml in 23 drug-free patients with major depression. The 24-hour urinary PAA excretion was also measured in 48 healthy volunteers (141.1 +/- 10.2 mg PAA/24 hr) and in 144 patients with major depression (78.2 +/- 41.0 mg PAA/24 hr). The results suggest that low plasma and urinary PAA may be state markers for depression and are compatible with the PEA hypothesis. In further support, phenylalanine elevated mood in 31 of 40 depressives.

GnRH receptors and actions in the control of reproductive function.

The hypothalamic control of reproductive function is expressed through the receptor-mediated actions of GnRH on the pituitary gonadotroph. GnRH receptors in the pituitary gland exhibit prominent variations in number during the ovarian cycle and after changes in steroid feedback, and are modulated by the rate of GnRH secretion from the hypothalamus. In cultured pituitary cells, GnRH receptors undergo down-regulation during exposure to GnRH agonists, followed by a subsequent elevation of sites that is dependent on protein synthesis. GnRH antagonists do not cause receptor down-regulation, but high-affinity antagonist analogs bind for extended periods to cause receptor occlusion and prolonged inhibition of GnRH action. Analysis of the rat pituitary GnRH receptor by photoaffinity labeling reveals two binding subunits of mol. wt 53,000 and 42,000. The receptor-activated processes leading to gonadotropin secretion are highly calcium-dependent, and are initiated by rapid phospholipid hydrolysis with production of arachidonic acid metabolites, diacylglycerol, and inositol phosphates. The role of protein kinase C in gonadotropin secretion is indicated by the ability of phorbol esters and synthetic diacylglycerols to stimulate LH release, the inhibition of protein kinase C and LH release by retinal, and the redistribution of protein kinase C between cytosol and membrane fractions during stimulation of pituitary gonadotrophs by GnRH. It is likely that the effects of arachidonate metabolites are integrated with those of calcium-calmodulin and calcium, phospholipid-dependent protein kinases during the immediate and sustained phases of GnRH-induced gonadotropin secretion.