Prostaglandin E2 suppresses phytohemagglutinin-induced immune responses of normal human mononuclear cells by decreasing intracellular glutathione generation, but not due to increased DNA strand breaks or apoptosis

Prostaglandin E2 (PGE2) at concentrations more than 1 x 10(-8) M markedly suppressed the cell proliferation and release of soluble molecules of interleukin-2 receptor (sIL-2R), CD4 (sCD4) and CD8 (sCD8) from phytohemagglutinin (PHA)-stimulated normal human mononuclear cells (MNC) in a dose-related manner. To further elucidate the subcellular mechanism of the inhibitory effect of PGE2 on PHA-stimulated MNC, intracellular concentration of glutathione (GSH) in PHA-stimulated MNC was sequentially measured from day 1 to day 3 by enzymic method. Furthermore, the effect of PGE2 on nuclear DNA including DNA strand breaks in alkali treatment and DNA fragmentation (apoptosis) of PHA-stimulated MNC were also measured. We found intracellular GSH levels were significantly decreased in the early stage of lymphocyte activation (day 1), but no evidence of increased DNA strand breaks or apoptotic process appeared in 3-day culture. In addition, butathione sulfoximine (a specific GSH inhibitor) and dibutyryl cyclic AMP also exhibited both proliferation inhibition and GSH-decreasing effects on PHA-stimulated MNC as well as PGE2. These results suggest that the immunosuppressive effect of PGE2 is mediated by the decreased generation of intracellular GSH, but not by the increased DNA strand breaks or apoptotic mechanism in the cells.

A rapid method for the measurement of cholesterol thermodynamic activity in bile salt-lecithin-cholesterol solutions

Earlier work from this laboratory suggested that the cholesterol (Ch) thermodynamic activity is a more meaningful measure of the degree of Ch supersaturation in human bile than the widely known cholesterol saturation index. An early version of a method for determining thermodynamic activity based on Ch uptake from bile salt (BS)-lecithin (LE) solutions into silicone polymer particles, but requiring 12-24 h for reaching equilibrium, was considered unsatisfactory because Ch nucleation and crystal formation frequently occurred within a few hours. The aim of the present work was to develop a method that would reduce equilibration times to the order of 1 h. Changing the thickness of the silicone film alone did not result in the desired reduction of equilibration times and it was soon deduced that the uptake of Ch by the silicone film from the BS-LE solution was a surface-controlled transport process involving the transport of Ch by negatively charged BS and BS-LE micelles at the interface. Three different approaches were tried to modify the silicone film to make its surface positively charged, thereby reducing and/or eliminating the presumed electrical repulsion barrier for the interfacial transport of Ch. The film was treated with different concentrations of aminopropyl methyl-dimethylsiloxane (AMDS) in cyclohexane, octadecyldimethyl-[3-(trimethoxysilyl)-propyl] ammonium chloride (ODTOP) in methanol, and octadecylamine solution in ethanol. Films treated with 1-1.5% ODTOP and 5-10% AMDS reduced the Ch equilibration times for model BS-LE solutions to < 1 h.

Adenomyoma of the papilla of Vater: a case report

Adenomyoma of the papilla of Vater is exceedingly rare. Histologically, the adenomyoma is characterized by locules of ducts with interlacing bundles of smooth muscle. A 63-year-old male patient is presented who had developed abdominal pain, progressively darker urine and light color stool, jaundice and dyspepsia over the past two-month period. Impression from radiologic study was neoplasm of the papilla of Vater, pathologic findings proved adenomyoma. This case, and review of the literature, suggest that local excision is the treatment-of-choice.

Cholesterol (thermodynamic) activity determinations in bile salt-lecithin-cholesterol systems and cholesterol-rich liquid crystalline mesophase formation

Previous in vitro studies have shown that tauroursodeoxycholate (TUDC)-lecithin (L) micellar solutions solubilize cholesterol (Ch) poorly compared to its 7 alpha-epimer, taurochenodeoxycholate (TCDC). However, in clinical studies ursodeoxycholic acid (UDC) has been found to be as effective as chenodeoxycholic acid (CDC) in Ch gallstone dissolution, and it has been suggested that, during UDC therapy, liquid crystalline mesophase formation may be involved in enhancing micellar Ch dissolution and dispersion. The purpose of the present study was to investigate whether measurements of the Ch thermodynamic activity (A(T) would provide new insights into the problem of Ch solubilization and mesophase formation in bile salt-lecithin-Ch systems. Using the silicone polymer uptake method developed in this laboratory, A(T) was measured as a function of Ch concentration in the TUDC-L-Ch and TCDC-L-Ch model bile systems. In the TCDC systems Henry's law was obeyed almost up to unit activity (i.e., A(T) was proportional to Ch concentration almost up to A(T) = 1.0). However, in many of the TUDC-containing systems negative deviations from Henry's law were observed well below unit activity and these systems became visibly turbid before saturation with respect to cholesterol monohydrate (ChM) was reached. The effects of varying the TCDC/TUDC ratio upon the A(T) behavior were also studied. With increasing TCDC/TUDC ratio, the onset of mesophase formation was shifted to higher A(T) values. A(T) measurements were also conducted in BS-L-Ch mixtures simulating biles of patients undergoing UDC therapy. The results obtained suggest that mesophase formation may not always occur in biles of patients undergoing UDC therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of hypercalcemia on renal sympathetic nervous system activity

Since calcium plays a modulatory role in the activity of the sympathetic nervous system (SNS), in these studies, we have tested the hypothesis that hypercalcemia may alter renal SNS activity, and, consequently, renal function. Acute hypercalcemia was induced in Sprague-Dawley rats by infusion of calcium 30 mg/kg/2 h in 0.45% saline. A control group of rats received only 0.45% saline. Two more groups of rats received either calcium or 0.45% saline 7-10 days after total renal denervation. Calcium infusion increased serum calcium by 1.8 +/- 0.23 mg/dl in rats with intact renal nerves and by 2.7 +/- 0.48 mg/dl in renal denervated rats. Mean arterial pressure and inulin clearance did not change during calcium or 0.45% saline in rats with intact renal nerves. Renal sympathetic nerve activity (RSNA) decreased by 44% in rats infused with calcium, but it did not change in control animals. Calcium caused a significantly greater rise in urine volume, sodium excretion and fractional excretion of sodium than the infusion of 0.45% saline. Rats with renal denervation manifested greater baseline urine volume, sodium excretion and fractional excretion of sodium than rats with intact renal nerves. Infusion of calcium, however, caused no further rise in urine sodium excretion in these animals. alpha-Methyltyrosine, an inhibitor of norepinephrine (NE) synthesis, also increased natriuresis in rats. Calcium reduced by 27% the NE content in the kidney but not in the heart. Methyltyrosine, on the other hand, reduced NE content in both the heart and the kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

An immunocytochemical study of effects of light deprivation on prolactin cells in the adenohypophysis of the golden hamster

Population ratio and morphology of prolactin cells were studied by employing immunohistochemical methods in the adenohypophysis of normal and experimental golden hamsters of both sexes at 16 weeks of age. Prolactin cells occupied 29% of the total adenohypophyseal cells in the intact males exposed to 14/10 h light/dark schedule. After stimulation of the pineal activity by binding or exposure of males to continuous darkness for eight weeks, prolactin cells became atrophic and were reduced in population to 17% and 13%, respectively. Pinealectomy prevented to some extent the effects of the above treatments; thus, prolactin cells constituted 27% in the pinealectomized and blinded hamsters, and 19% in the pinealectomized and darkness-treated group; and their morphology was comparable with that of the intact controls. Prolactin cells in the normal females were apparently larger in size and more numerous as compared with those of the normal males, comprising 47% of cell population in the anterior pituitary. In response to light deprivation, prolactin cells were atrophic with a diminished cytoplasm and decreased in cell number as reflected in the population ratio of 27% in the blinded and 21% in the darkness-treated groups. In pinealectomized females combined with binding or darkness-treatment, prolactin cells contained an abundance of secretory granules in the cytoplasm and maintained the population ratio comparable to that in the intact females. The present study revealed that light deprivation exerts an inhibitory effect on the secretory activity of prolactin cells and also causes hypoplasia of prolactin cells in the hamster adenohypophysis, the effects being mediated by the pineal gland.

Equilibrium dialysis studies on aqueous taurocholate-lecithin solutions: further validation of the method

Since the 1980 publication by Mazer, Benedek and Carey on the concept of the simple micelle-mixed micelle coexistence phenomenon in the bile salt-lecithin systems, it became apparent that a reliable method was needed for measuring the coexisting species concentrations. We recently published a method based on membrane dialysis equilibrium, and the purpose of this report is to review and to validate this previous work. In the present studies, two dialysis membranes with molecular weight cut-off of 8,000 and 12,000 to 14,000 Da, respectively, and two sets of solution volume conditions were investigated with the taurocholate-lecithin system. Coexistence data were obtained over a wide range of lecithin concentrations and the results were found to be in good agreement with those from the previous studies. The bile salt/lecithin molar ratios for the mixed micelles were also deduced from the data. The principal conclusion of this study is that although there is a moderate amount of variability (10% to 15%), the method is both satisfactory and useful in studying bile salt-lecithin equilibria and dynamics.

An acrylic head appliance for craniomaxillary fixation

An acrylic head appliance for the treatment of LeFort fractures is described. The appliance remains stable and effective during the course of treatment. When immobilization is no longer needed, it may be removed without anesthetizing the patient.

In vitro effects of magnesium on ionized calcium concentration in serum

Hypermagnesemic neonates, born to mothers receiving magnesium (Mg) sulfate before delivery, have elevated ionized calcium (iCa) concentrations in serum. We hypothesized that this elevation might be due in part to competition of Mg with calcium (Ca) bound to proteins or complexed to salts. Serum and its ultrafiltrate were obtained from five placental blood samples. The iCa concentration was measured in both serum and its ultrafiltrate at five incremental Mg concentrations (delta Mg) up to 6.58 mmol/L. In both serum and ultrafiltrate, incremental iCa (delta iCa) correlated significantly with delta Mg. By multiple regression analysis, delta ica in serum correlated positively with delta Mg in serum and negatively with albumin concentration in serum. Thus, iCa concentration in serum is increased in vitro by hypermagnesemia; it appears that Mg may compete with Ca bound to albumin and complexed to salts.

Formate dehydrogenase molybdenum and tungsten sites--observation by EXAFS of structural differences

Preliminary EXAFS data has been collected on the molybdenum (K-edge) in C. pasteurianum formate dehydrogenase and the tungsten (LIII-edge) in C. thermoaceticum formate dehydrogenase. In the presence of dithionite, the tungsten enzyme was devoid of W = O bonds, and exhibited average W-(O, N) and W-S bond lengths of 2.13 +/- 0.03 A and 2.39 +/- 0.03 A, respectively. In sharp contrast, the C. pasteurianum molybdenum site has three Mo = O bonds with an average bond length of 1.74 +/- 0.03 A. It is also the first molybdenum enzyme found lacking Mo-S bonds, and does not appear to be redox active in the presence of formate or dithionite. Model compounds WO2(8-hydroxyquinoline)2 = WO2(ox)2, and WO2(8 mercaptoquinoline)2 = WO2(tox)2, were also examined. Respective predicted bond lengths for WO2(ox)2 and WO2(tox)2 were W = O of 1.71, 1.73 A; W-N of 2.31, 2.29 A; W-O or W-S of 1.92 or 2.40 A, with estimated uncertainties of +/- 0.03 A.

Formate dehydrogenase of Clostridium pasteurianum

Formate dehydrogenase was purified to electrophoretic homogeneity from N2-fixing cells of Clostridium pasteurianum W5. The purified enzyme has a minimal Mr of 117,000 with two nonidentical subunits with molecular weights of 76,000 and 34,000, respectively. It contains 2 mol of molybdenum, 24 mol of nonheme iron, and 28 mol of acid-labile sulfide per mol of enzyme; no other metal ions were detected. Analysis of its iron-sulfur centers by ligand exchange techniques showed that 20 iron atoms of formate dehydrogenase can be extruded as Fe4S4 centers. Fluorescence analysis of its isolated molybdenum centers suggests it is a molybdopterin. The clostridial formate dehydrogenase has a pH optimum between 8.3 and 8.5 and a temperature optimum of 52 degrees C. The Km for formate is 1.72 mM with a Vmax of 551 mumol of methyl viologen reduced per min per mg of protein. Sodium azide competes competitively with formate (K1 = 3.57 microM), whereas the inactivation by cyanide follows pseudo-first-order kinetics with K = 5 X 10(2) M-1 s-1.

Inorganic Pyrophosphate: Energy Source for Sulfate-Reducing Bacteria of the Genus Desulfotomaculum

Sulfate-reducing bacteria belonging to the genus Desulfotomaculum utilized inorganic pyrophosphate as a source of energy for growth in the presence of fixed carbon (acetate and yeast extract) and sulfate. Pyrophosphate does not support the growth of Desulfovibrio under the same growth conditions. Over a limited range of concentrations, growth is proportional to pyrophosphate, and extracts of bacteria grown on pyrophosphate medium have enzymatic activities similar to extracts prepared from bacteria grown on medium containing lactate plus sulfate. The variety of cell types observed in crude anaerobic pyrophosphate-enrichment cultures from a marine environment suggests that this unique type of energy metabolism is not restricted to the sulfate-reducing bacteria of the genus Desulfotomaculum.

Comparative bioenergetics of sulfate reduction in Desulfovibrio and Desulfotomaculum spp

Extracts of Desulfotomaculum nigrificans, Desulfotomaculum orientis, and Desulfotomaculum ruminis exhibit low levels of inorganic pyrophosphatase but were found to have high levels of pyrophosphate:acetate phosphotransferase. Conversely, extracts of Desulfovibrio gigas, Desulfovibrio vulgaris, and Desulfovibrio desulfuricans Norway 4 were shown to have high levels of inorganic pyrophosphatase but negligible amounts of pyrophosphate:acetate phosphotransferase. Both enzymes are reductant activated and appear to have an analogous function in removing pyrophosphate formed during the activation of sulfate. Conservation of the bond energy of pyrophosphate in Desulfotomaculum eliminates the necessity for invoking electron-transfer-coupled phosphorylation to account for the growth of these bacteria on lactate plus sulfate. Relative growth yields of Desulfovibrio vulgaris and Desulfotomaculum orientis on lactate plus sulfate indicate that the latter does not carry out significant electron-transfer-coupled phosphorylation in this mode of growth.

Experimentally produced resistance of Schistosoma mansoni to hycanthone

Genetically transferred resistance to the antischistosomal drug hycanthone has been observed in several strains of Schistosoma mansoni: 1) in the progeny of worms to whose hosts hycanthone had been administered 54 to 70 days after exposure to cercariae (Type I); 2) in the progeny of worms to whose hosts hycanthone had been administered when the worms were still in an immature stage (27 to 29 days after percutaneous cercarial exposure) (Type II); and 3) in the progeny of worms from hosts that had been infected with cercariae of one sex followed by infection with the opposite sex 2 to 58 weeks later (Type III). In types I and II, drug resistance was transferred maternally. Hycanthone-resistant schistosomes were cross-resistant to antischistosomal drugs structurally related to hycanthone, such as oxamniquine and two chloro-indazole analogs of hycanthone, but not to niridazole and to another nitroheterocyclic compound.

Inhibition by metrifonate and dichlorvos of cholinesterases in schistosomes

1. No species differences between Schistosoma haematobium and Schistosoma mansoni were detected when the I50 of metrifonate for the acetylcholinesterases (AChE) and the cholinesterases (ChE) of these two trematodes were determined in isolated enzyme preparations or following exposure of the intact worms to this drug in vitro.2. S. haematobium appeared to be more affected by AChE inhibition because, after administration of metrifonate to hamsters, a hepatic shift of the parasites was observed with a dose of metrifonate (150 mg (0.6 mmol) per kg) which produced no shift of S. mansoni, although AChE inhibition was comparable in both species.3. Administration of a possible metabolite of metrifonate, dichlorvos, to hamsters resulted in a greater inhibition of AChE and ChE activities of S. haematobium than those of S. mansoni. Furthermore, when schistosomes were incubated with dichlorvos, inhibition of AChE activity of female S. haematobium was significantly greater (P<0.005) than that of both sexes of S. mansoni and of male S. haematobium.4. The discrepancy between the lack of a significant chemotherapeutic effect of metrifonate in hamsters infected with S. haematobium and the clinical results obtained with this organophosphorus compound in human schistosomiasis haematobium is discussed, and the need to conduct similar studies in primates is pointed out.