Effect of protamine sulfate on the permeability properties of the mammalian urinary bladder

Protamine sulfate (PS, an arginine-rich protein of molecular weight 5,000) has been reported to affect the ionic permeability of gallbladder epithelium, the permeability of cultured epithelial cells to mannitol, and the permeability of endothelial cell layers to albumin. Although the effect of PS has been widely investigated, the mechanism of its action on membrane permeability is presently unknown. The effect of PS on the rabbit urinary bladder epithelium was studied using both transepithelial and intracellular microelectrode techniques in conjunction with equivalent circuit analysis. The addition of 100 micrograms/ml of PS to a NaCl-containing mucosal solution caused (over a 40-min period) a large increase in the transepithelial conductance (Gt) and a transient hyperpolarization of the transepithelial voltage (Vt) followed by a depolarization of Vt. This secondary depolarization of Vt was not present if the mucosal solution was a KCl or a K-gluconate Ringer. The PS-induced increase in Gt was due to an increase in the apical membrane permeability to both cations (Na+ or K+) and anions (Cl- or gluconate). Further studies revealed the following features of the PS-induced conductance. (i) Trypsin inhibits the PS effect; however, this was due to PS hydrolysis by trypsin and not a membrane effect. (ii) Mucosal PS partially inhibited the PS-induced apical membrane conductance. (iii) The ability of PS to increase the membrane conductance was enhanced when the apical membrane potential was cell interior negative. (iv) The rate of conductance change (at any given membrane potential) was a saturating function of the PS concentration. This finding suggests that PS must interact with a membrane binding site before it can induce a change in the membrane conductance. (v) Lanthanum inhibited the PS-dependent conductance by two different mechanisms. One was as a reversible blocker of the PS-induced conductance. The other was by inhibiting the interaction between PS and a membrane binding site. A kinetic model is developed to describe the steps involved in the increase in membrane conductance.

The role of eggs in mercury excretion by Quail Coturnix coturnix and the implications for monitoring mercury pollution by analysis of feathers

: This paper describes differences in the excretion of methyl mercury between male and female Quail Coturnix coturnix after a single dose. Since feathers are often used to monitor mercury pollution it is important to take into account biases in feather mercury levels that may arise as a result of mercury loss through egg-laying. Evidence is presented to support the use of bird eggs to sample for environmental mercury contamination. Birds were monitored up to twelve weeks after administration. Mercury concentrations in the kidney exceeded those in the liver which exceeded those in the pectoral muscle. Significant differences in mercury levels between male and female birds were found up to eight weeks after administration. Mercury was initially distributed through most of the internal tissues and was lost relatively slowly in a negative exponential manner. Mercury loss through excretion differed between the sexes for the first eight weeks after mercury administration. Initial mercury concentration in eggs was 3.5 μg g(-1) but no mercury was detected in eggs five weeks after the dose was administered. At this point over 40% of the females' intake had been lost into the eggs.

Mercury levels in eggs, tissues, and feathers of herring gulls Larus argentatus from the German Wadden Sea Coast

The relationships between mercury levels in eggs, tissues, and feathers of male and female herring gulls caught at their nests at a colony on the German Wadden Sea Coast were investigated, and an assessment of mercury intake and excretion of these birds was made. Samples of the liver, ovary, pectoral muscle, and body feathers, as well as the primary feather (in some cases), and eggs were taken from 37 adult herring gulls. Analysis of total mercury in all samples showed that body-feather and tissue levels were independent of sex. There was, however, a significant difference between levels of mercury in the primary feathers of male and female birds. Egg levels were not correlated to pectoral muscle, ovary, or feather levels although they were positively correlated with mercury levels in the liver. Liver levels were in turn correlated with mercury levels in the ovary. The ratio of mean feather to mean egg concentration ranged from 3.7 to 5.5 according to which feather was used. It was estimated that herring gulls from the Wadden coast ingested between 825 and 1337 microg of mercury in the year prior to analysis. It was also estimated that female birds may excrete over 20% more mercury via their eggs than could be excreted by male birds.

Protection of swine against foot-and-mouth disease with viral capsid proteins expressed in heterologous systems

Three groups of swine were each inoculated with a different antigen preparation of foot-and-mouth disease virus (FMDV) capsid proteins and challenged by contact exposure to animals infected with FMDV. One group of four animals was inoculated with an extract from cells infected with a recombinant baculovirus containing the FMDV P1-2A structural protein precursor gene and a portion of the P2 gene. Two out of four animals were protected from clinical disease, but not from virus replication. A second group of animals was inoculated with an extract from Escherichia coli that expressed FMDV proteins from a construct containing the P1-2A gene, a portion of the P2 gene and the 3C protease gene. Three out of four animals in this group did not develop clinical signs of FMD upon challenge and two of four were protected against virus replication. In contrast, inoculation of a third group of swine with an extract from E. coli expressing the same FMDV construct as present in the recombinant baculovirus failed to protect any of the four animals from generalized FMD.

Comparison of a modification of the ellman method to measure carbamate inhibition of acetylcholinesterase in plasma, erythrocytes and brain tissues in sprague dawley rats using two analytical systems

Inhibition of the enzyme acetylcholinesterase (AChE) using a carbamate compound was measured in 30 Crl: CD(R)BR Sprague Dawley rats. Erythrocyte, plasma, and brain tissues were analyzed using modifications of the Ellman technique(1) on two different clinical chemistry analyzers. Both EDTA and heparin anticoagulated whole blood were used for the erythrocyte and plasma tests. Results demonstrated similar inhibition of the enzyme in all three tissues between the control and dosed groups using the two technique modifications and instruments. Final inhibition of plasma and erythrocyte AChE for the control vs. treated groups (males and females combined) was 89.5% vs. 82% and 39% vs. 38% for the Technicon AutoAnalyzertrade mark vs. the Boehringer Mannheim Hitachitrade mark 704, respectively. Inhibition of the left and right brain segments for the control vs. treated groups (males and females combined) was 35% vs. 39% and 33.2% vs. 29% for the Technicon and the Hitachi, respectively. All inhibitions were significant at the 5% level using two tailed Dunnett's t-Test. Hemolysates prepared from EDTA whole blood packed cells gave more consistent results on the Hitachi 704.

RP 58802B, a long-acting beta 2-adrenoceptor agonist: assessment of antiasthma activity in the guinea-pig in vivo

We have examined the protective actions of RP 58802B, a novel beta 2-adrenoceptor agonist, administered by the inhaled and oral routes in the anaesthetized and conscious guinea-pig against bronchospasm induced by histamine or antigen (ovalbumin). We have also examined the effects of RP 58802B on airway reactivity and inflammatory cell infiltration in platelet-activating factor (PAF) (aerosol)-induced bronchial hyperreactivity and on PAF (tracheal instillation)-induced microvascular leakage in the guinea-pig. Nebulized RP 58802B produced a rapid onset and long lasting inhibition of histamine-induced bronchospasm in the anaesthetized guinea-pig (EC50 = 3.2 +/- 0.9 micrograms/ml; duration greater than 90 min). Given orally, RP 58802B (5 mg/kg, 60 min before challenge) produced a greater than three-fold shift to the right of the dose-response curve and depressed the maximum response to histamine by 39 +/- 11%. Increasing the concentration to 25 mg/kg had no futher effect. Similar protection was still seen 4 h after oral dosing. In conscious guinea-pigs, RP 58802B (5 or 25 mg/kg, p.o. 60 min before challenge) significantly attenuated antigen-induced dyspnoea with the time to severe dyspnoea increasing from 170 +/- 32 to 325 +/- 32 s at the higher dose of drug. RP 58802B (10 or 25 mg/kg, p.o. 60 min before exposure to PAF) prevented the development of bronchial hyperreactivity. Although PAF-induced bronchial hyperreactivity was not accompanied by an increase in the number of pulmonary eosinophils, RP 58802B (25 mg/kg p.o.) reduced the numbers of eosinophils recovered by lavage. RP 58802B (10 mg/kg p.o.) significantly inhibited PAF-induced microvascular leakage into guinea-pig lung. These data suggest that RP 58802B, in addition to being a potent and long acting bronchodilator, may have a prophylactic role in preventing bronchial hyperreactivity and in reducing plasma exudation into the lungs.

A Technique for Evaluating Heterodera glycines Development in Susceptible and Resistant Soybean

A technique was developed to evaluate Heterodera glycines development in susceptible and resistant soybean. Roots of 3-day-old soybean were exposed to infective juveniles of H. glyci.nes in sand for 8 hours followed by washing and transfer to hydroponic culture. The cotyledons and apical meristem were removed and plants were maintained under constant light, which resulted in a dwarfed plant system. After 15 or 20 days at 27 C, nematodes were rated for development. Emerged males were sieved from the culture water and females were counted directly from the roots. Nematodes remaining in the roots were rated for development after staining and clearing the tissues. The proportion of nematodes at each stage of development and the frequency of completed molts for each stage were calculated from these data. This technique showed that resistance to H. glycines was stage related and did not affect males and females equally in all resistant hosts. The resistance of plant introduction PI 209332 primarily affected development of third and fourth-stage juveniles; 'Pickett' mainly affected second and third-stage juveniles, whereas PI 89772 affected all stages. Male development was markedly affected in PI 89772 and 'Pickett' but not in PI 209332.

Genomic RFLP Analysis of Meloidogyne arenaria Race 2 Populations

Traditional morphological methods of Meloidogyne identification have been unsuccessful in distinguishing three South Carolina, USA Meloidogyne arenaria race 2 populations-Govan, Pelion, and Florence. These populations differ greatly in reproductive rate and aggressiveness on soybean hosts. Total genomic DNA from eggs of each population was digested with the restriction endonuclease Eco RI and Southern hybridization analyses were performed with single-copy and interspersed multi-copy cloned probes. Probes were isolated from a genomic library of Eco RI, M. arenaria DNA fragments cloned into pUC8. One probe, designated pE1.6A, when hybridized to Southern blots of M. arenaria genomic DNAs, displayed an interspersed repetitive pattern, and the RFLPs distinguished the Govan population from the Pelion and Florence populations. Another clone, pE6.0A, carrying moderately repeated sequences, distinguished the Pelion and Florence isolates. This communication demonstrates the utility of genomic RFLP analysis for distinguishing populations of the same race within the same species. To test the possible utility of these moderately repeated sequence probes for detecting the presence of nematode DNA in DNA samples from roots inoculated with varying numbers of nematodes, dot blot hybridization analyses were performed. It is possible to detect as few as 30 nematodes per root sample with these cloned probes.

Identification and characterization of the structural and nonstructural proteins of African horsesickness virus and determination of the genome coding assignments

Proteins present in purified African horsesickness virus (AHSV) and in infected cells were analyzed by SDS-polyacrylamide gel electrophoresis. Twelve viral proteins were identified, one minor and four major structural proteins, three major and two minor nonstructural proteins, as well as variable amounts of two additional structural proteins. Cell-free translation of total AHS virion RNA in a rabbit reticulocyte system resulted in the synthesis of proteins which were qualitatively and quantitatively similar to those found in infected cells. The in vivo and in vitro synthesized proteins were viral specific as demonstrated by immunoprecipitation. The coding assignments of all the purified genome segments were determined by in vitro translation and confirmed by immunoprecipitation.

RP 59227, a novel PAF receptor antagonist: effects in guinea pig models of airway hyperreactivity

The PAF antagonists RP 59227 and WEB 2086 (100 micrograms.kg-1 i.v., 10 min prior to platelet-activating factor (PAF) infusion) abolished or reduced (P less than 0.05) hyperreactivity to bombesin measured at 1 h. Similarly, RP 59227 and WEB 2086 (10 mg.kg-1 p.o., 1 h prior to PAF aerosol) abolished or reduced (P less than 0.01) hyperreactivity to bombesin measured at 24 h. Lower concentrations of RP 59227 and WEB 2086 (3 mg.kg-1 p.o.) were without effect. RP 59227 or WEB 2086 (3 or 10 mg.kg-1 p.o., 1 h prior to antigen aerosol) did not protect against antigen-induced hyperreactivity to histamine measured at 24 h. Antigen-(but not PAF)-induced hyperreactivity was accompanied by an increase in total cell number and, specifically, eosinophil number in bronchoalveolar lavage fluid. The PAF antagonists did not affect BALF cell populations. It is concluded that RP 59227 and WEB 2086 are potent PAF antagonists which inhibit PAF-but not antigen-induced airway hyperreactivity. These data suggest that endogenous PAF may not be involved in antigen-induced hyperreactivity in the guinea pig.

A spectroscopic method for assessing confluence of epithelial cell cultures

We describe a convenient nonelectrophysiological technique for assessing cell proliferation and subsequent tight junction formation for epithelial monolayers grown on permeable supports. The method involves the use of phenol red (PR), a standard pH indicator in most cell culture media. In addition, we report a systematic error in a commercially available system for measuring transepithelial electrical properties. Briefly, the flux of PR across the epithelium was measured from the serosal solution into the mucosal solution. The mucosal solution was first replaced with a PR-free solution and then collected at timed intervals. The PR concentration was measured using a spectrophotometer set at the isosbestic point for PR (479 nm). PR flux was then calculated and used as an index of the permeability of the epithelium to PR. This method was tested using the renal epithelial cell line A6. After cell seeding, PR flux decreased in two phases: an initial large decrease, associated with cell growth and monolayer confluence, and a second decrease associated with tight junction formation [assessed by measuring transepithelial conductance (Gt)]. In addition to monitoring tight junction formation, PR flux measurements were also used to estimate the net movement of solution by the epithelial cells between the mucosal and serosal compartments. For convenience, Gt was initially measured in culture dishes using a commercially available "chopstick" electrode system. However, the chopstick system yielded Gt values that were on average 51% lower than values for the same preparations when measured in standard Ussing-type chambers. The discrepancy was due to a nonuniform current field produced by the chopstick electrodes.

Expression, processing, and assembly of foot-and-mouth disease virus capsid structures in heterologous systems: induction of a neutralizing antibody response in guinea pigs

Plasmids containing the foot-and-mouth disease virus structural protein precursor (P1) and 3C protease genes or the P1 gene alone were expressed in Escherichia coli. A recombinant baculovirus containing the P1 gene was also generated and expressed in Spodoptera frugiperda cells. Expression of the P1 and 3C genes in E. coli resulted in efficient synthesis and processing of the structural protein precursor and assembly into 70S empty capsids. This material reacted with neutralizing monoclonal antibodies which recognize only conformational epitopes and elicited a significant neutralizing antibody response in vaccinated guinea pigs. Expression of the P1 gene in E. coli resulted in synthesis of an insoluble product, whereas in insect cells infected with the recombinant baculovirus a soluble product was synthesized. Both soluble and insoluble P1 reacted with a 12S-specific monoclonal antibody, but only soluble P1 elicited a neutralizing antibody response in guinea pigs.

Transport-related modulation of the membrane properties of toad urinary bladder epithelium

Impedance analysis and transepithelial electrical measurements were used to assess the effects of the apical membrane Na+ channel blocker amiloride and anion replacement on the apical and basolateral membrane conductances and areas of the toad urinary bladder (Bufo marinus). Mucosal amiloride addition decreased both apical and basolateral membrane conductances (Ga and Gbl, respectively) with no change in membrane capacitances (Ca and Cbl). Consequently, the specific conductances of these membranes decreased without significant changes in membrane area. Following amiloride removal, an increase was obtained in the steady-state rate of sodium transport compared to values before amiloride addition. This increase was independent of the initial transport rate, suggesting activation of a quiescent pool of apical sodium channels. Chloride replacement by acetate or gluconate had no significant effects on apical or basolateral membrane capacitances. The effects of these replacements on membrane conductances depended on the anion species. Gluconate (which induces cell shrinkage) decreased both membrane conductances. In contrast, acetate (which induces cell swelling) increased Ga and had no effect on Gbl. The increase in the apical membrane conductance was due to an increase in the amiloride-sensitive Na+ conductance of this membrane. In summary, mucosal amiloride addition or chloride replacements led to changes in membrane conductances without significant effects on net membrane areas.

Meloidogyne arenaria Populations on Soybean

The distribution of Meloidogyne spp. was determined in the Piedmont and Coastal Plains soybean production areas of South Carolina. Meloidogyne arenaria, M. incognita, and M. javanica were found in six of seven counties surveyed, with some populations consisting of two or more species. Because M. arenaria populations did not reproduce on peanut (Arachis hypogaea cv. Florunner), they were designated as Host Race 2. Severity of root galling, shoot and root growth, seed yield, and nematode reproduction were examined in fields infested with M. arenaria at Govan and Pelion, South Carolina, using soybean cultivars differing in host suitability to M. arenaria. When different responses in shoot and root growth, seed yield, and nematode reproduction in the two locations were found, soil influences were examined in duplicate field microplot experiments. Soybean growth was affected more by soil influences than by nematode populations; however, the two M. arenaria populations differed in amount of galling and rate of reproduction.

Urinary proteases degrade epithelial sodium channels

The mammalian urinary bladder epithelium accommodates volume changes by the insertion and withdrawal of cytoplasmic vesicles. Both apical membrane (which is entirely composed of fused vesicles) and the cytoplasmic vesicles contain three types of ionic conductances, one amiloride sensitive, another a cation-selective conductance and the third a cation conductance which seems to partition between the apical membrane and the mucosal solution. The transport properties of the apical membrane (which has been exposed to urine in vivo) differ from the cytoplasmic vesicles by possessing a lower density of amiloride-sensitive channels and a variable level of leak conductance. It was previously shown that glandular kallikrein was able to hydrolyze epithelial sodium channels into the leak conductance and that this leak conductance was further degraded into a channel which partitioned between the apical membrane and the mucosal solution. This report investigates whether kallikrein is the only urinary constituent capable of altering the apical membrane ionic permeability or whether other proteases or ionic conditions also irreversible modify apical membrane permeability. Alterations of mucosal pH, urea concentrations, calcium concentrations or osmolarity did not irreversible affect the apical membrane ionic conductances. However, urokinase and plasmin (both serine proteases found in mammalian urine) were found to cause an irreversible loss of amiloride-sensitive current, a variable change in the leak current as well as the appearance of a third conductance which was unstable in the apical membrane and appears to partition between the apical membrane and the mucosal solution. Amiloride protects the amiloride-sensitive conductance from hydrolysis but does not protect the leak pathway. Neither channel is protected by sodium. Fluctuation analysis demonstrated that the loss of amiloride-sensitive current was due to a decrease in the sodium-channel density and not a change in the single-channel current. Assuming a simple model of sequential degradation, estimates of single-channel currents and conductances for both the leak channel and unstable leak channel are determined.

Aggressiveness and Reproduction of Four Meloidogyne arenaria Populations on Soybean

Aggressiveness and reproduction differed among four geographical populations of M. arenaria on six soybean cultivars in field microplots. These differences were consistent over 3 years. The populations did not differ in virulence; i.e., population by cultivar interactions were not significant. Perineal pattern morphology, the North Carolina differential host test, chromosome counts of immature oocytes, and esterase phenotypes confirmed that the four populations were M. arenaria. Three populations were host race 2 and one population was host race 1.

Characterization of proteins and immunogens released by adult Schistosoma mansoni

The proteins released in vitro by metabolically radiolabeled adult Schistosoma mansoni were identified by 2-dimensional gel electrophoresis. To determine the origin of these proteins, adult worms were fractionated into surface membrane, tegument, and remaining body components, and the electrophoretic patterns of the proteins in the 3 fractions were compared to those of the released proteins. The immunogens present in these fractions then were identified by immunoprecipitation with sera from humans infected with S. mansoni. This analysis indicated that essentially all of the proteins released from the worm were immunogenic, whereas most of the major membrane and tegumental proteins were not reactive with the immune sera. Thus, it appears that the adult worm is defended against immune attack by detection of the host's antibody response against released proteins rather than against proteins-exposed on the worm's surface.

Vectorial secretion of a kallikrein-like enzyme by cultured renal cells. I. General properties

Urinary kallikreins are proteolytic enzymes known to be secreted by distal nephron tubules. In this study, we demonstrate (using the chromogenic tripeptide substrate S 2266) that the renal cell line A6 from Xenopus laevis secretes a kallikrein-like enzyme. Secretion is present only when the cells are grown on filters, and enzyme is secreted only into the apical membrane bathing solution. Enzyme secretion consists of two components, one soybean trypsin inhibitor (SBTI) sensitive (SSBTI) and the other insensitive to SBTI (ISBTI). Both enzymes were inhibited by aprotinin, a kallikrein-like enzyme inhibitor. Using a bioassay, only the ISBTI enzyme produced a hypotensive effect on blood pressure and is thus a kallikrein-like enzyme. The apical membrane of cells grown on filters contains both enzyme species, whereas the basolateral membrane contains only the ISBTI (kallikrein-like) enzyme. Both enzymes were present in the apical membrane of cells grown on plastic. Initiation of enzyme secretion occurred after the cells formed electrically tight monolayers and the increase in membrane activity always preceded enzyme secretion. Using an irreversible inhibitor of the apical membrane-bound enzymes, the turnover rate for the SSBTI and ISBTI enzymes (cells on filters) was 3 and 7 h, respectively. Because the recovery of enzyme secretion was proportional to the recovery of membrane-bound enzyme activities, this suggests that enzyme secretion is due to the release of membrane-bound enzyme.

Clinical and angiographic recurrence following PTCA for nonacute total occlusions: comparison of one- versus five-minute inflations

To assess potential efficacy of longer inflations to reduce restenosis, 49 patients with nonacute total occlusions were randomized into two groups after successful guide wire passage across the occlusive stenosis. Twenty-one group I patients had all inflations less than 1 minute, while 28 group II patients received at least one inflation of 5 minutes' duration. There was no significant difference between group I and group II patients in mean age (56 +/- 3 versus 57 +/- 2 years), percent male sex (76% versus 68%), or frequency of left anterior descending (LAD) percutaneous transluminal coronary angioplasty (PTCA) (33% versus 32%), p = NS for all. All lesions post PTCA were less than or equal to 50% stenosed and no patient had coronary artery bypass surgery (CABG). Mean post PTCA stenosis was 29 +/- 2% for group I versus 33 +/- 2% for group II, p = NS. Clinical follow-up was available for all patients 8 +/- 0.6 months after PTCA. Recurrent symptoms were present in 8 of 21 (38%) group I patients compared with 12 of 28 (43%) patients in group II, p = NS. Angiographic follow-up was available in 32 patients (65%), with confirmation of restenosis in seven (33%) group I patients and in 11 (39%) group II patients, p = NS. In conclusion, this prospective study suggests that recurrence rates following successful PTCA of nonacute total occlusions is not modified by 5-minute versus 1-minute inflations.

Ion Channels and Cell Volume Regulation: Chaos in an Organized System

Exposure of many vertebrate cells to solutions more dilute or concentrated than the physiological "norm" results in an initial increase or decrease in cell volume followed by a recovery of volume toward a normal value. Although the basic strategy for volume regulation is the same for cell types studied, the mechanism by which the cell regulates ion channels appears to be tissue dependent.

Bluetongue virus: surface exposure of VP7

The exposed proteins of bluetongue virus serotype 17 were determined using surface labeling and reactivity with monoclonal antibodies. Iodination of amino groups predominantly labeled VP2; however, iodination of tyrosine residues labeled both VP2 and VP5, with VP7 labeled to a significantly lesser degree. To investigate the exposure of VP7 on the intact virion further, monoclonal antibodies that reacted with this protein were used. At least two antibodies, reacting with different epitopes on VP7, bound to intact virions, as determined by adsorption of infectious particles, electron microscopic observation of antibody-bound virus, and co-sedimentation of antibody and virus. Surface iodination of viral cores was used to show that VP7 and VP3 are major exposed proteins on these particles. We conclude that a major core protein, VP7, has at least two epitopes exposed on the virus surface.