Correlation between vascular and cellular responses to atrial natriuretic peptide and to sodium nitroprusside

Atrial natriuretic peptide (ANP) and sodium nitroprusside (SNP) increase cGMP in vascular smooth muscle cells and act as vasodilators in some, but not all, blood vessels. In this present study, we attempted to correlate the ability of these two agents to dilate blood vessels with the ability to increase cGMP in cultured vascular smooth muscle cells. In the isolated guinea pig heart, SNP dose-dependently increased coronary flow while ANP was ineffective. In smooth muscle cells cultured from the coronary system, SNP increased intracellular cGMP in a dose-dependent manner while ANP had no effect on cGMP in these cells. In isolated guinea-pig thoracic aorta, precontracted with K+, both ANP and SNP produced relaxation and ANP was the more potent. In smooth muscle cells cultured from the aorta, ANP and SNP increased cGMP and the potency relationship was similar to the intact vessel. These results support the view that phenotypic properties of vascular smooth muscle cells can account for differences in the response of blood vessels to vasodilators.     

N- and O-glycosylation muteins of recombinant human erythropoietin secreted from BHK-21 cells

Single-site glycomuteins of recombinant human erythropoietin (rhuEpo) were constructed and transiently and stably expressed in BHK-21 cells. The transient expression levels varied among muteins, being highest for mutein rhuEpoGln24 followed by wild-type rhuEpo (rhuEpowt). All other glycomuteins, including rhuEpoGln38, rhuEpoGln83, rhuEpoThr126, and rhuEpoGly126, were secreted at lower levels than rhuEpowt. Muteins expressed in stable cell lines showed similar differences in expression levels. Also each mutein could be affinity-purified from culture supernatants, and was biologically active in vivo. Based on secretion rates from BHK-21 cells, the most potent erythropoietin was rhuEpoGln24. This mutein is also considered to have biologic activities that are superior to rhuEpowt.     

Novel expression and regulation of gastrin gene in human ovarian cancer cell line, SW626

Gastrin-secreting tumors have been identified in ectopic locations including the ovary; the mechanisms regulating gastrin gene expression, its distribution, and signaling pathways in these ectopic tissues are not known. The purpose of our present study was to determine: (1) whether the gastrin gene and peptide could be detected in ovarian cancer cell lines, (2) if functional gastrin releasing peptide receptors (GRP-R) are present, and (3) whether gastrin gene expression is altered by GRP. Five ovarian cancer cell lines (SW626, OVCA 420, OVCA 429, OVCA 432, and OVCA 433) were analyzed. We identified gastrin gene and peptide expression in the SW626 cell line but not in the OVCA lines. SW626 cells express a functional GRP-R that is correctly coupled to the Ca2+ signaling pathway. Treatment of SW626 cells with bombesin, the amphibian equivalent of GRP, inhibited expression of the gastrin gene in a time- and dose-dependent fashion. The SW626 ovarian cancer cell line will provide a useful model to further define regulation and expression of both the gastrin gene and peptide in ectopic (nongastrointestinal) tissues.     

The use of controlled-release oxycodone for the treatment of chronic cancer pain: a randomized, double-blind study

1. We have studied the effects of muscarinic cholinoceptor agonists and subtype-preferring antagonists on the isometric contraction of smooth muscle strips from dog prostate. 2. Acetylcholine and carbachol induced contraction of prostate strips from the peripheral zone, ('the capsule'). Bethanechol contracted the tissue but not at lower doses. McN-A-343 and oxotremorine-M showed the same effects. 3. Blocking alpha- and beta-adrenoceptors with phentolamine and propranolol, respectively, did not modify carbachol-induced contractions. 4. The nicotinic receptor blocker, hexamethonium (10(-6)-10(-4) M) did not affect the contractile response evoked by a single dose of carbachol (10(-5) M), whilst the muscarinic receptor antagonist, atropine (10(-11)-10(-9) M), inhibited it in a competitive manner. 5. The muscarinic M1 (pirenzepine), M2 [AF-DX 116, himbacine (M2/M4) and methoctramine], M3 (HHSID and f-F-HHSID), and putative M4 (tropicamide) antagonists reduced significantly the carbachol-induced contractions. The pIC50 values were: atropine (10.01) > himbacine (8.3) > methoctramine (7.85) > AF-DX 116 (7.60) > HHSID (7.21) > p-F-HHSID (7.10) > pirenzepine (7.30) > tropicamide (7.00). 6. The antagonist profile indicates that an predominant M2 receptor subtype could mediate the muscarinic contraction in the canine prostate.     

Role of Epstein-Barr virus in fine-needle aspirates of metastatic neck nodes in the diagnosis of nasopharyngeal carcinoma

The crystal structure of the peptide Boc-Phe-Val-OMe determined by X-ray diffraction methods is reported in this paper. The crystals grown from aqueous methanol are orthorhombic, space group P2(1)2(1)2(1),a = 11.843(2), b = 21.493(4), c = 26.676(4) A3 and V = 6790 A3. Data were collected on a CAD4 diffractometer using MoK alpha radiation (lambda = 0.7107 A) up to Bragg angle theta = 26 degrees. The structure was solved by direct methods and refined by a least-squares procedure to an R value of 6.8% for 3288 observed reflections. There are three crystal-lographically independent peptide molecules in the asymmetric unit. All the three molecules exhibit extended conformation. The sidechain of the Val2 residue shows two different conformations. The conformation of the peptide Boc-Phe-Val-OMe is compared with the conformation of Ac-delta Phe-Val-OH. It is observed that while Boc-Phe-Val-OMe exhibits an extended conformation, Ac-delta Phe-Val-OH shows a folded conformation. The results of this comparison highlight the conformation constraining property of the delta Phe residue. Interestingly, even though Boc-Phe-Val-OMe and Ac-delta Phe-Val-OH are conformationally different, they exhibit similar packing patterns in the solid state.     

Aggressive experience affects the sensitivity of neurons towards pharmacological treatment in the hypothalamic attack area

Early investigators of brain stimulation-evoked complex behaviours (attack, escape, feeding, self-grooming, sexual behaviour) reported that experience may affect the behavioural outcome of brain stimulation. This intriguing example of functional neuronal plasticity was later totally neglected. The present experiment investigated the behavioural outcome of in vivo microdialysis perfusion of the glutamate agonist kainate and/or the GABAA antagonist bicuculline into the hypothalamic attack area (HAA) of (1) animals naive to dyadic encounters; (2) animals with a recent aggressive experience (the probe being implanted 6-24 h after the last of a series of dyadic encounters); and (3) animals with an earlier aggressive experience (probe being implanted 2 weeks after the last aggressive experience). On the experimental day, rats received two 5-min infusions during a dyadic encounter lasting 35 min with an unknown opponent. Flow rate was 1.5-2 microliters/min, drug concentrations were 1.8 x 10(-5) and 1.5 x 10(-5) M for kainate and bicuculline, respectively. Behaviour was analysed before, during and after perfusions. Only the combined kainate + bicuculline treatment had significant effects on behaviour at the doses studied. A significant increase in aggressive behaviour was elicited only in animals with a recent aggressive experience, while naive animals and with an earlier experience responded to the treatments by grooming. These results appear to support early observations indicating that one important aspect of brain stimulation effects is previous experience.