Transdermal iontophoresis of gonadotropin releasing hormone (LHRH) and two analogues

Gonadotropin releasing hormone (GnRH), as well as an antagonist [Ac-D2Nal,1 D4ClPhe,2 D3Pal,3 NicLys,5 DNicLys,6 ILys,8 DAla10] GnRH.HOAc (1) and a superagonist [DTrp6, Pro9-NHEt]GnRH (2), have been electrochemically driven across excised hairless mouse skin. Determined by HPLC analysis, the delivery rate from aqueous solution into isotonic saline at 0.5 mA cm-2 was as high as 19 nM cm-2 h-1 for 2. Because of its insolubility in water, analogue 1 could only be delivered from an acidic donor solution. Analogue 2 was also delivered in pulsatile fashion using current on/off cycles. For all three peptides, passive transport was negligible and stability is evident when in contact with the stratum corneum. Slow metabolism occurs when GnRH contacts the dermal side of hairless mouse skin.     

Partial reversal of the hypogonadotropic hypogonadism of obese men by administration of corticosuppressive doses of dexamethasone

Obese men have hyperestrogenemia-induced hypogonadotropic hypogonadism (HHG), due, we believe, to increased rarmatization of adrenal androgens by the increased bulk of aromatase-containing adipose tissue. We studied the effects of corticosuppressive doses of dexamethasone (D) on 24-h mean plasma total and free estradiol (E2), estrone (E1), LH, FSH, total and free testosterone, delta 4-androstenedione (delta 4), and sex-hormone-binding globulin (SHBG) in nine obese men and five normal-weight controls. In the obese men, the following hormones fell: E2 [59 +/- 19 to 39 +/- 11 pg/ml (P less than 0.01)], E1 [93 +/- 41 to 50 +/- 25 pg/ml; (P less than 0.01)], delta 4-androstenedione [120 +/- 80 to 55 +/- 27 ng/dl; (P less than 0.02)]; free E2 [1.6 +/- 0.4 to 1.1 +/- 0.2 pg/ml; (P less than 0.01)], SHBG [12.8 +/- 5.3 to 8.2 +/- 3 nM/l; (P less than 0.04)]. FSH rose from 4.8 +/- 3.2 to 7.6 +/- 4.2 miu/ml (P less than 0.01). LH, total and free testosterone showed no significant change. In the nonobese men, there were decreases in total E2 [(34 +/- 6.8 to 25 +/- 10 pg/ml; P less than 0.04)], SHBG [16.8 +/- 7.5 to 10.4 +/- 2.0 nM/l: P less than .05.], free E2 [0.9 +/- 0.2 to 0.7 +/- 0.3 pg/ml: P less than 0.05], delta 4 [91.4 +/- 3.6 to 33.4 +/- 16.7 ng/dl; P less than .01] and total T [492 +/- 44 to 393 +/- 121 ng/dl; P less than 0.04]. There was no significant change in E1, FSH, LH or free T.(ABSTRACT TRUNCATED AT 250 WORDS)     

Flow-induced cerebral vasodilatation in vivo involves activation of phosphatidylinositol-3 kinase, NADPH-oxidase, and nitric oxide synthase.

Reactive oxygen species (ROS) such as superoxide (O2*-) and hydrogen peroxide (H2O2) are known cerebral vasodilators. A major source of vascular ROS is the flavin-containing enzyme nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase. Activation of NADPH-oxidase leads to dilatation of the basilar artery in vivo via production of H2O2, but the endogenous stimuli for this unique vasodilator mechanism are unknown. Shear stress is known to activate both NADPH-oxidase and phosphatidylinositol-3 kinase (PI3-K) in cultured cells. Hence, this study used a cranial window preparation in anesthetized rats to investigate whether increased intraluminal blood flow could induce cerebral vasodilatation via the activation of NADPH-oxidase and/or PI3-K. Bilateral occlusion of the common carotid arteries to increase basilar artery blood flow caused reproducible, reversible vasodilatation. Topical treatment of the basilar artery with the NADPH-oxidase inhibitor diphenyleneiodonium (DPI) (0.5 and 5 micromol/L) inhibited flow-induced dilatation by up to 50% without affecting dilator responses to acetylcholine. Treatment with the H2O2 scavenger, catalase similarly attenuated flow-induced dilatation, suggesting a role for NADPH-oxidase-derived H2O2 in this response. The nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) partially reduced flow-induced dilatation, and combined treatment with a ROS inhibitor (DPI or catalase) and L-NAME caused a greater reduction in flow-induced dilatation than that seen with any of these inhibitors alone. Flow-induced dilatation was also markedly inhibited by the PI3-K inhibitor, wortmannin. Increased O2*- production in the endothelium of the basilar artery during acute increases in blood flow was confirmed using dihydroethidium. Thus, flow-induced cerebral vasodilatation in vivo involves production of ROS and nitric oxide, and is dependent on PI3-K activation.     

Metabotropic glutamate receptors mediate excitatory transmission in the nucleus of the solitary tract.

Following microinjection into the nucleus tractus solitarius (NTS), the effects of glutamate on the baroreceptor reflex are poorly antagonized by kynurenic acid and DL-2-amino-5-phosphonovaleric acid, suggesting the possible involvement of metabotropic glutamate receptors in this response. The metabotropic glutamate receptor agonist 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) depolarized neurons located medial to the tractus solitarius (TS) at the level of the area postrema in coronal sections of the rat NTS. This effect was mimicked by glutamate and was not blocked by antagonists at alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA)/kainate or NMDA receptors. 1S,3R-ACPD also produced an inward current under voltage clamp that was not accompanied by a rise in [Ca2+]i, monitored with the Ca(2+)-sensitive dye fura-2. Conversely, the muscarinic agonist carbachol produced an outward current and a rise in [Ca2+]i. 1S,3R-ACPD reduced both the excitatory and the inhibitory postsynaptic current resulting from single electrical stimuli in the region of the TS. High-frequency stimulation of the TS produced an inward current in the presence of AMPA/kainate and NMDA receptor blockers. This current had similar properties to that produced by 1S,3R-ACPD. Thus, metabotropic glutamate receptors may mediate a component of excitatory transmission in the NTS.     

Ileosigmoid knotting: a case report and review.

Ileosigmoid knotting, or compound volvulus, has not been reported previously in Australia. A 41 year old woman of Anglo-Saxon origin presented with a short history of extreme abdominal pain that was out of proportion to her physical findings. At operation it was found that her entire ileum was tightly knotted around the redundant, twisted sigmoid colon. Both closed loops were gangrenous and it was impossible to unravel the bowel. She recovered uneventfully following resection and primary anastomosis of both portions of the intestine. Most patients with this uncommon condition have been reported from Finland and eastern Africa. An arrangement of the small bowel and sigmoid colon on long, narrow mesenteries would appear to be a prerequisite. The brevity of the history and the severity of the abdominal pain call for early laparotomy. Prolonged attempts to untie the knot are dangerous. It is safer to divide the ileum at the knot and resect it in order to release the sigmoid colon. Primary anastomosis is feasible where the history is short and the uninvolved intestine is clean and collapsed.