Modulation of whole body protein metabolism, during and after exercise, by variation of dietary protein

The aim of this study was to investigate dietary protein-induced changes in whole body leucine turnover and oxidation and in skeletal muscle branched chain 2-oxo acid dehydrogenase (BCOADH) activity, at rest and during exercise. Postabsorptive subjects received a primed constant infusion of L-[1-13C,15N]leucine for 6 h, after previous consumption of a high- (HP; 1.8 g . kg-1 . day-1, n = 8) or a low-protein diet (LP; 0.7 g . kg-1 . day-1, n = 8) for 7 days. The subjects were studied at rest for 2 h, during 2-h exercise at 60% maximum oxygen consumption, then again for 2 h at rest. Exercise induced a doubling of both leucine oxidation from 20 micromol . kg-1 . h-1 and BCOADH percent activation from 7% in all subjects. Leucine oxidation was greater before (+46%) and during (+40%, P < 0.05) the first hour of exercise in subjects consuming the HP rather than the LP diet, but there was no additional change in muscle BCOADH activity. The results suggest that leucine oxidation was increased by previous ingestion of an HP diet, attributable to an increase in leucine availability rather than to a stimulation of the skeletal muscle BCOADH activity.     

FTIR characterization of heterocycles lumazine and violapterin in solution: effects of solvent on anionic forms

Fourier transform infrared (FTIR) spectra have been obtained from solution samples of the heterocycles uracil, lumazine, and violapterin and reveal interpretable carbonyl stretching frequencies. Spectra of conjugate bases of lumazine and violapterin demonstrate decreases in these carbonyl stretching frequencies upon ionization. Based on isotopic shifts from amide deuterated analogs, semiempirical QCFF/PI calculations were used to assign the vibrational frequencies in the region 1100-1800 cm-1 observed from samples in dimethylsulfoxide (DMSO) and aqueous solutions to specific normal modes. The observed deuterium shifts and the calculations suggest that, in some cases, N-H bending motions are coupled to the C=O stretching motions of the pyrimidine ring. These data suggest that for lumazine anions a change in solvent can significantly change the mixing of the N-H bending and C=O stretching vibrational motions. This implies that vibrational analysis for lumazine species in relatively noninteracting media like nonpolar solvents, mulls or pellets cannot necessarily be transferred to the system when it is dissolved in a polar, hydrogen-bonding solvent such as water. Although other explanations can be offered, our vibrational analysis suggests that the changes in normal mode composition of the predominantly C=O stretching vibrations of lumazine anion on going from dimethylsulfoxide to water solution are consistent with a change in the predominant tautomer of the heterocycle. This change appears to correspond to a shifting of the location of the remaining acidic proton to a different ring nitrogen atom. This interpretation is of interest in view of recent ab initio calculations which suggest that proton shifts may occur during the hydroxylation of lumazine as mediated by the enzyme xanthine oxidase.     

Platynosomum fastosum in ex-captive orangutans from Indonesia

The liver fluke Platynosomum fastosum was identified upon necropsy of three ex-captive orangutans (Pongo pygmaeus) which had been part of a rehabilitation program for reintroduction to the wild. This trematode has not been reported in orangutans previously and is commonly found in cats in Southeast Asia. Cross infection from cats via intermediate hosts, to orangutans kept in captivity as pets, could explain their presence in the latter. Although P. fastosum caused intrahepatic and bile duct damage, death of the hosts could not be attributed solely to the presence of the liver fluke infection.     

Prospective study on the influence of gastroduodenal ulcer hemorrhage on the diagnostic methods in Helicobacter pylori infection]

Peripheral giant cell granuloma consists of mononuclear cells and osteoclast-like giant cells. The proliferative ability of peripheral giant cell granuloma is restricted to the mononuclear cell compartment, whereas multinucleated giant cells lack mitotic activity. Although the proliferative compartment of peripheral giant cell granuloma has been investigated in detail, the expression and distribution of proteins regulating apoptosis is unknown. The present study demonstrates strong expression of bak and bax in the majority of giant cells. In contrast, giant cells show only weak positivity for bcl-2 and moderate positivity for bcl-x. Mononuclear cells were negative to weakly positive for bcl-x. Only scattered mononuclear cells were positive for bak, bax and bcl-2. The frequency of apoptotic nuclei detected by TUNEL-staining compared to regular nuclei was 18 times higher in giant cells than in mononuclear cells. In summary, our findings support the presumption that giant cells of bone and soft tissue tumors are reactive cell forms and not of neoplastic origin.     

A prospective 12-year study of subsyndromal and syndromal depressive symptoms in unipolar major depressive disorders

BACKGROUND: Investigations of unipolar major depressive disorder (MDD) have focused primarily on major depressive episode remission/recovery and relapse/recurrence. This is the first prospective, naturalistic, long-term study of the weekly symptomatic course of MDD. METHODS: The weekly depressive symptoms of 431 patients with MDD seeking treatment at 5 academic centers were divided into 4 levels of severity: (1) depressive symptoms at the threshold for MDD; (2) depressive symptoms at the threshold for minor depressive or dysthymic disorder (MinD); (3) subsyndromal or subthreshold depressive symptoms (SSDs), below the thresholds for MinD and MDD; and (4) no depressive symptoms. The percentage of weeks at each level, number of changes in symptom level, and medication status were analyzed overall and for 3 subgroups defined by mood disorder history. RESULTS: Patients were symptomatically ill in 59% of weeks. Symptom levels changed frequently (1.8/y), and 9 of 10 patients spent weeks at 3 or 4 different levels during follow-up. The MinD (27%) and SSD (17%) symptom levels were more common than the MDD (15%) symptom level. Patients with double depression and recurrent depression had more chronic symptoms than patients with their first lifetime major depressive episode (72% and 65%, respectively, vs 46% of follow-up weeks). CONCLUSION: The long-term weekly course of unipolar MDD is dominated by prolonged symptomatic chronicity. Combined MinD and SSD level symptoms were about 3 times more common (43%) than MDD level symptoms (15%). The symptomatic course is dynamic and changeable, and MDD, MinD, and SSD symptom levels commonly alternate over time in the same patients as a symptomatic continuum of illness activity of a single clinical disease.     

Effect of beta-adrenergic agonists on paracellular width and fluid flow across outflow pathway cells

PURPOSE: To determine whether the adrenergic agonists epinephrine and isoproterenol regulate fluid flow across endothelial cells cultured from the human aqueous outflow pathway and to evaluate associated cellular mechanisms. METHODS: Confluent monolayers of human trabecular meshwork (TM) or Schlemm's canal endothelial (SCE) cells were grown on porous filter supports. The monolayers were perfused with media while fluid flow, expressed as hydraulic conductivity (HC = microl/min/mm Hg/cm2), was continuously measured in preparations treated with isoproterenol, epinephrine, or control medium. Morphometric ultrastructural methods were used to measure the area occupied by the intercellular space and by each cell. RESULTS: SCE cells and TM cells exposed to isoproterenol or epinephrine responded with an increase in transendothelial fluid flow. Dose-response curves for both adrenergic agonists showed that HC increased linearly as a function of the log of the isoproterenol and epinephrine concentration. At 10(-4) M isoproterenol, the HC increased threefold, and threshold conditions were reached at 10(-9) M. The increase in HC was apparent after isoproterenol had been applied for 1 hour, reached a peak in 3 to 4 hours, and declined gradually to return to baseline conditions in 10 to 12 hours. Morphometric analyses showed that the area occupied by the intercellular space increased fourfold when isoproterenol was used at 10(-4) M, whereas the cell area decreased as a function of the concentration of adrenergic agonist. Epinephrine's effects on HC and cell morphology were blocked by pretreatment with equimolar concentrations of the nonselective beta-blocker, timolol. CONCLUSIONS: Epinephrine and isoproterenol increase flow through the paracellular pathway of SCE and TM cells through a beta-receptor mediated response that widens the intercellular space and reduces cell area. These findings support the hypothesis that epinephrine decreases the intraocular pressure in glaucoma therapy by promoting fluid flow across the SCE and TM cells lining tissues of the major aqueous outflow pathway.     

Use of cyclodextrins in capillary electrophoresis: resolution of tramadol enantiomers

Capillary zone electrophoresis was successfully applied to the enantiomeric resolution of racemic tramadol. Both uncoated and polyacrylamide-coated capillaries were tested for method optimization using either negatively charged or native cyclodextrins (CD) added to the background electrolyte (BGE). The resolution was strongly influenced by the CD type and concentration as well as by the pH and the concentration of the BGE. Among the CDs tested, carboxymethylated-beta-cyclodextrin allowed the baseline separation of tramadol enantiomers. After the method was optimized, it was validated in a coated capillary for enantiomeric analysis of tramadol enantiomers in pharmaceutical formulation, including specificity and elution order, linearity, accuracy and precision, determination of limit of detection (LOD) and quantification (LOQ), enantiomeric purity linearity, freedom from interference, and stability of sample solutions. Precision at the target concentration was less than 2%, with an accuracy higher than 99%. Furthermore, the method was able to detect 0.3% and to quantify 1% of the minor enantiomer in the presence of the major one at the target value.     

Regulation of cardiac myocyte contractile function by inducible nitric oxide synthase (iNOS): mechanisms of contractile depression by nitric oxide

Inflammatory cytokines have been implicated in the reversible depression of cardiac contractile function accompanying local or systemic immune stimulation. Incubation of cardiac myocytes with soluble components in the supernatant from cultured rat lung macrophages activated with endotoxin decreases their contractile response to beta-adrenergic stimulation through the induction of iNOS and the subsequent production of nitric oxide by these cells. In the present study, we characterize the mechanisms underlying NO's attenuation of adrenergic responsiveness in cardiac myocytes. iNOS was induced in cultured ventricular myocytes from adult rats by incubation for 20 h with conditioned medium from lipopolysaccharide (LPS)-activated macrophages. iNOS induction did not induce any alteration in beta-adrenergic receptor density or affinity, Galphai protein abundance, or adenylyl cyclase activity in cultured myocytes. Myocyte exposure to activated macrophage-conditioned medium markedly attenuated the elevation of cAMP in response to isoproterenol (Iso, 2 nM). Induction of iNOS with the macrophage-conditioned medium also potentiated the Iso-induced increase in myocyte cGMP. This cGMP increase was totally abolished by NOS inhibitors. NOS inhibition also returned the attenuated cAMP response to 2 nM Iso to levels observed in control cells. Pre-incubation of the cells in isobutylmethylxanthine (IBMX), a phosphodiesterase inhibitor, also partly reversed the attenuation of cAMP increase with 2 nM Iso in cells expressing iNOS. Brief (15 min) exposure of myocytes to the NO donor, S-nitrosoacetylcysteine (SNAC, 100 micro M) which produced a three-fold increase in intracellular cGMP, also decreased by half the contractile response of cardiac myocytes to Iso (2 nM). We conclude that NO endogenously produced by iNOS decreases the intracellular levels of cAMP in response to beta-adrenergic stimulation in isolated cardiac myocytes, in part through a cGMP-mediated mechanism. This effect may participate in the NO-dependent depression of cardiac function following cytokine exposure.