Strong Base Anion Exchange Selectivity of Nine Perfluoroalkyl Chemicals Relevant to Drinking Water

Selectivity with respect to chloride (K PFAS ∕ C ) was determined for nine drinking water relevant perfluoroalkyl and polyfluoroalkyl substances (PFAS): perfluoro-2-propoxypropanoic acid (GenX), five perfluoroalkyl carboxylic acids (PFCAs), and three perfluoroalkyl sulfonic acids (PFSAs). Three single-use strong base anion exchange gel resins were investigated, targeting drinking water relevant equilibrium PFAS liquid concentrations (≤500 ng/L). Except for the longest carbon chain PFCA (perfluorodecanoic acid) and PFSA (perfluorooctanesulfonic acid) studied, PFAS followed traditional ion exchange theory (law of mass action), including increasing equilibrium PFAS liquid concentrations with increasing equilibrium chloride liquid concentrations. Overall, K PFAS ∕ C values were (i) similar among resins for a given PFAS, (ii) 1-5 orders of magnitude greater than the selectivity of inorganic anions (e.g., nitrate) previously studied, (iii) 2 orders of magnitude greater for the same carbon chain length PFSA versus PFCA, (iv) found to proportionally increase with carbon chain length for both PFSAs and PFCAs, and (v) similar for GenX and perfluorohexanoic acid (six-carbon PFCA). A multisolute competition experiment demonstrated binary isotherm-determined K PFAS ∕ C values could be applied to simulate a multisolute system, extending work previously done with only inorganic anions to PFAS. Ultimately, estimated K PFAS ∕ C values allow future extension and validation of an open-source anion exchange column model to PFAS.

Role of grinding method on granular activated carbon characteristics

A coconut shell (AC1230CX) and a bituminous coal based (F400) granular activated carbon (GAC) were ground with mortar and pestle (MP), a blender, and a bench-scale ball milling unit (BMU). Blender was the most time-efficient for particle size reduction. Four size fractions ranging from 20 × 40 to 200 × 325 were characterized along with the bulk GACs. Compared to bulk GACs, F400 blender and BMU 20 × 40 fractions decreased in specific surface area (SSA, -23% and -31%, respectively) while smaller variations (-14% to 5%) occurred randomly for AC1230CX ground fractions. For F400, the blender and BMU size fraction dependencies were attributed to the combination of (i) radial trends in the F400 particle properties and (ii) importance of shear (outer layer removal) versus shock (particle fracturing) size reduction mechanisms. Compared to bulk GACs, surface oxygen content (At%-O1s) increased up to 34% for the F400 blender and BMU 20 × 40 fractions, whereas all AC1230CX ground fractions, except for the blender 100 × 200 and BMU 60 × 100 and 100 × 200 fractions, showed 25-29% consistent increases. The At%-O1s gain was attributed to (i) radial trends in F400 properties and (ii) oxidization during grinding, both of which supported the shear mechanism of mechanical grinding. Relatively small to insignificant changes in point of zero charge (pH_PZC) and crystalline structure showed similar trends with the changes in SSA and At%-O1s. The study findings provide guidance for informed selection of grinding methods based on GAC type and target particle sizes to improve the representativeness of adsorption studies conducted with ground GAC, such as rapid small-scale column tests. When GACs have radial trends in their properties and when the target size fraction only includes larger particle sizes, manual grinding is recommended.

Anion Exchange Resin and Inorganic Anion Parameter Determination for Model Validation and Evaluation of Unintended Consequences during PFAS Treatment

When implementing anion exchange (AEX) for per- and polyfluoroalkyl substances treatment, temporal drinking water quality changes from concurrent inorganic anion (IA) removal can create unintended consequences (e.g., corrosion control impacts). To understand potential effects, four drinking water-relevant IAs (bicarbonate, chloride, sulfate, and nitrate) and three gel-type, strong-base AEX resins were evaluated. Batch binary isotherm experiments provided estimates of IA selectivity with respect to chloride (K x ∕ C ) for IA/resin combinations where bicarbonate < sulfate ≤ nitrate at studied conditions. A multi-IA batch experiment demonstrated that binary isotherm-determinedK x ∕ C values predicted competitive behavior. Subsequent column experiments with and without natural organic matter (NOM) allowed for the validation of a new ion exchange column model (IEX-CM; https://github.com/USEPA/Water_Treatment_Models). IA breakthrough was well-simulated using binary isotherm-determinedK x ∕ C values and was minimally impacted by NOM. Initial AEX effluent water quality changes with corrosion implications included increased chloride and decreased sulfate and bicarbonate concentrations, resulting in elevated chloride-to-sulfate mass ratios (CSMRs) and Larson ratios (LRs) and depressed pH until the complete breakthrough of the relevant IA(s). IEX-CM utility was further illustrated by simulating the treatment of low-IA source water and a change in the source water to understand the resulting duration of changes in IAs and water quality parameters.

Sequence-Defined Macrocycles for Understanding and Controlling the Build-up of Hierarchical Order in Self-Assembled 2D Arrays

Anfinsen's dogma that sequence dictates structure is fundamental to understanding the activity and assembly of proteins. This idea has been applied to all manner of oligomers but not to the behavior of cyclic oligomers, aka macrocycles. We do this here by providing the first proofs that sequence controls the hierarchical assembly of nonbiological macrocycles, in this case, at graphite surfaces. To design macrocycles with one (AAA), two (AAB), or three (ABC) different carbazole units, we needed to subvert the synthetic preferences for one-pot macrocyclizations. We developed a new stepwise synthesis with sequence-defined targets made in 11, 17, and 22 steps with 25, 10, and 5% yields, respectively. The linear build up of primary sequence (1°) also enabled a thermal Huisgen cycloaddition to proceed regioselectively for the first time using geometric control. The resulting macrocycles are planar (2° structure) and form H-bonded dimers (3°) at surfaces. Primary sequences encoded into the suite of tricarb macrocycles were shown by scanning-tunneling microscopy (STM) to impact the next levels of supramolecular ordering (4°) and 2D crystalline polymorphs (5°) at solution-graphite interfaces. STM imaging of an AAB macrocycle revealed the formation of a new gap phase that was inaccessible using only C3-symmetric macrocycles. STM imaging of two additional sequence-controlled macrocycles (AAD, ABE) allowed us to identify the factors driving the formation of this new polymorph. This demonstration of how sequence controls the hierarchical patterning of macrocycles raises the importance of stepwise syntheses relative to one-pot macrocyclizations to offer new approaches for greater understanding and control of hierarchical assembly.

Stem cell-derived neurons from autistic individuals with SHANK3 mutation show morphogenetic abnormalities during early development

Shank3 is a structural protein found predominantly at the postsynaptic density. Mutations in the SHANK3 gene have been associated with risk for autism spectrum disorder (ASD). We generated induced pluripotent stem cells (iPSCs) from control individuals and from human donors with ASD carrying microdeletions of SHANK3. In addition, we used Zinc finger nucleases to generate isogenic SHANK3 knockout human embryonic stem (ES) cell lines. We differentiated pluripotent cells into either cortical or olfactory placodal neurons. We show that patient-derived placodal neurons make fewer synapses than control cells. Moreover, patient-derived cells display a developmental phenotype: young postmitotic neurons have smaller cell bodies, more extensively branched neurites, and reduced motility compared with controls. These phenotypes were mimicked by SHANK3-edited ES cells and rescued by transduction with a Shank3 expression construct. This developmental phenotype is not observed in the same iPSC lines differentiated into cortical neurons. Therefore, we suggest that SHANK3 has a critical role in neuronal morphogenesis in placodal neurons and that early defects are associated with ASD-associated mutations.

Determination of iron sites and the amount of amorphization in radiation-damaged titanite (CaSiTiO5)

Iron is a ubiquitous impurity in metamict (radiation-damaged and partially amorphized) materials such as titanite (CaSiTiO(5)). Using (57)Fe Mössbauer spectroscopy we find that iron in metamict titanite is partitioned between amorphous and crystalline regions based on valence. Trivalent iron exists in the crystalline titanite matrix whereas divalent iron exists almost exclusively in radiation-amorphized regions. We find that the relative abundances of the oxidation states correlate with the volume fraction of amorphous and crystalline regions. Our data also show that oxidation of iron proceeds along with the recrystallization of the amorphized regions. Recrystallization is confirmed to occur over the range 700 °C < T < 925 °C, and no further structural changes are observed at higher temperatures. It is surprising that our Mössbauer measurements show divalent iron to be surrounded by titanite with a high degree of short-range structural order in the amorphized regions. This observation is fundamentally different from other metamict materials such as zircon (ZrSiO(4)), where amorphized regions show no short-range order.

Dog obesity: owner attitudes and behaviour

Animal (dog) factors that contribute to obesity are classified into three broad categories: genetic pre-disposition, reproductive management and dietary/exercise (human) management. This paper examined the latter-dietary/exercise (human) management. A quantitative analysis of questionnaire responses from dog owners and veterinarians was used to determine the routine care and obesity management strategies for dogs. A total of 550 questionnaires were distributed to dog owners in Victoria, Australia. Owners were asked to score the body condition of their animal by comparison with photographic images of animals with condition score ranging from 2 to 5. The management routines of 219 dog owners were received, including data on 302 dogs. There were 168 households with normal weight animals (BCS 2 and 3) and 51 with obese animals (BCS 4 and 5). The mean number of people per household (normally involved with caring for the animal(s)) with normal weight dogs was significantly lower than that of households with dogs categorised as overweight or obese (Kruskal-Wallis, Chi; chi(2)=6.28; 2.2 (s=0.79) vs. 2.5 (s=1.66); d.f.=2, P<0.05). Dog owners identified a preference for main meal feeding of 'twice a day' (60%), followed by 'once daily' (33%), 'greater than or equal to three times daily' (2%), and 'always feed available' (5%). There was a significant difference (Chi; chi(2)=6.30; d.f.=1; P<0.05) in the frequency of main meal feeding between households. Normal weight animals had food divided into two portions, whereas obese animals or animals from mixed households were more often fed their meal in either one or three-plus portions. Almost all owners fed treats (99%) in the daily feed. Households with normal weight dogs gave treats significantly less frequently than households with obese or mixed weight dogs (Chi; chi(2)=31.81; d.f.=6; P<0.001). The frequency of exercise differed between households (Chi; chi(2)=9.9; d.f.=1; P<0.01), with normal weight dogs being exercised daily compared to weekly for overweight or mixed weight dogs. Owners who indicated that their dog was confined to a yard as its exercise regime rather than walked were also significantly more likely to be an obese or mixed weight household (Chi; chi(2)=18.4; d.f.=1; P<0.001). In conclusion, there is clear evidence that obesity in dogs is affected by the interrelationships between food management, exercise and social factors.

Origin of the Verwey transition in magnetite

Comprehensive x-ray powder diffraction studies were carried out in magnetite in the 80-150 K and 0-12 GPa ranges with a membrane-driven diamond anvil cell and helium as a pressure medium. Careful data analyses have shown that a reversible, cubic to a distorted-cubic, structural transition takes place with increasing pressure, within the (P,T) regime below the Verwey temperature TV(P). The experimental documentation that TV(P)=Tdist(P) implies that the pressure-temperature-driven metal-insulator Verwey transition is caused by a gap opening in the electronic band structure due to the crystal-structural transformation to a lower-symmetry phase. The distorted-cubic insulating phase comprises a relatively small pressure-temperature range of the stability field of the cubic metallic phase that extends to 25 GPa.

The influence of whole grain inclusion in pelleted broiler diets on proventricular dilatation and ascites mortality

1. Pelleted diets, incorporating whole or ground wheat or barley in the pellets, were fed to broiler chickens and proventricular dilatation, digesta characteristics and mortality were recorded. 2. The incidence of proventricular dilatation was reduced when whole grain was incorporated into pelleted diets at 200 g/kg. 3. Enzyme application did not influence proventricular dilatation. 4. Digesta contents of intestinal sections were greater and pH lower in anterior intestinal sections when birds had dilated proventriculi. 5. Consideration of overall ascites mortality suggests that the incidence of the condition may be curtailed by whole grain inclusion in pelleted diets. 6. Production efficiency may be enhanced with whole grain inclusion in pellets when feed processing costs and flock health responses are considered.

The incorporation of whole grain into pelleted broiler chicken diets. II. Gastrointestinal and digesta characteristics

1. Pelleted diets, incorporating whole or ground wheat or barley in the pellets, were fed to broiler chickens and the performance, gastrointestinal development and digesta characteristics of those chickens recorded. 2. Body weight was similar with whole grain incorporation or enzyme application. Food conversion efficiency was improved by addition of enzyme to a full wheat diet. 3. Whole grain inclusion in pellets reduced proventriculus proportional mass and increased gizzard proportional mass with no apparent effects of exogenous feed enzyme addition. 4. Relative ileal mass was reduced by enzyme inclusion in a wheat diet and by inclusion of whole barley in the pellets. 5. Digesta viscosity was increased by whole wheat inclusion but reduced by enzyme inclusion irrespective of grain processing. Inclusion of 200 g/kg of barley did not alter viscosity of digesta beyond the duodenum. 6. Fresh excreta pH was higher with both cereals in the grower phase when whole grain was fed. On the barley diet, this was affected by enzyme addition, which created higher pH from a point earlier in the grower phase than when no enzyme was employed. 7. Evidence of a complex interaction between higher viscosity and pH being involved in differences in ileal relative mass was found through significant relationships being produced by enzyme use on the wheat diet alone.

Pressure induced self-oxidation of Fe(OH)2

Mössbauer spectroscopy, x-ray diffraction, and electrical resistance [R(P,T)] studies in Fe(OH)(2) to 40 GPa revealed an unforeseen process by which a gradual Fe2+ oxidation takes place, starting at approximately 8 GPa reaching 70% Fe3+ abundance at 40 GPa. The nonreversible process Fe2+-->Fe3++e(-) occurs with no structural transition. The "ejected" electrons form a deep band within the high-pressure electronic manifold becoming weakly localized at P>50 GPa. This process is attributed to an effective ionization potential created by the pressure induced orientationally deformed (OH) dipoles and the unusual small binding energy of the valence electron in Fe2+(OH)(2).

A review of protein-small molecule docking methods

The binding of small molecule ligands to large protein targets is central to numerous biological processes. The accurate prediction of the binding modes between the ligand and protein, (the docking problem) is of fundamental importance in modern structure-based drug design. An overview of current docking techniques is presented with a description of applications including single docking experiments and the virtual screening of databases.

TANK2, a new TRF1-associated poly(ADP-ribose) polymerase, causes rapid induction of cell death upon overexpression

Tankyrase (TANK1) is a human telomere-associated poly(ADP-ribose) polymerase (PARP) that binds the telomere-binding protein TRF1 and increases telomere length when overexpressed. Here we report characterization of a second human tankyrase, tankyrase 2 (TANK2), which can also interact with TRF1 but has properties distinct from those of TANK1. TANK2 is encoded by a 66-kilobase pair gene (TNKS2) containing 28 exons, which express a 6.7-kilobase pair mRNA and a 1166-amino acid protein. The protein shares 85% amino acid identity with TANK1 in the ankyrin repeat, sterile alpha-motif, and PARP catalytic domains but has a unique N-terminal domain, which is conserved in the murine TNKS2 gene. TANK2 interacted with TRF1 in yeast and in vitro and localized predominantly to a perinuclear region, similar to the properties of TANK1. In contrast to TANK1, however, TANK2 caused rapid cell death when highly overexpressed. TANK2-induced death featured loss of mitochondrial membrane potential, but not PARP1 cleavage, suggesting that TANK2 kills cells by necrosis. The cell death was prevented by the PARP inhibitor 3-aminobenzamide. In vivo, TANK2 may differ from TANK1 in its intrinsic or regulated PARP activity or its substrate specificity.

Structural requirements of Tom40 for assembly into preexisting TOM complexes of mitochondria

Tom40 is the major subunit of the translocase of the outer mitochondrial membrane (the TOM complex). To study the assembly pathway of Tom40, we have followed the integration of the protein into the TOM complex in vitro and in vivo using wild-type and altered versions of the Neurospora crassa Tom40 protein. Upon import into isolated mitochondria, Tom40 precursor proteins lacking the first 20 or the first 40 amino acid residues were assembled as the wild-type protein. In contrast, a Tom40 precursor lacking residues 41 to 60, which contains a highly conserved region of the protein, was arrested at an intermediate stage of assembly. We constructed mutant versions of Tom40 affecting this region and transformed the genes into a sheltered heterokaryon containing a tom40 null nucleus. Homokaryotic strains expressing the mutant Tom40 proteins had growth rate defects and were deficient in their ability to form conidia. Analysis of the TOM complex in these strains by blue native gel electrophoresis revealed alterations in electrophoretic mobility and a tendency to lose Tom40 subunits from the complex. Thus, both in vitro and in vivo studies implicate residues 41 to 60 as containing a sequence required for proper assembly/stability of Tom40 into the TOM complex. Finally, we found that TOM complexes in the mitochondrial outer membrane were capable of exchanging subunits in vitro. A model is proposed for the integration of Tom40 subunits into the TOM complex.

The incorporation of whole grain into pelleted broiler chicken diets: production and physiological responses

1. Pelleted diets, incorporating whole or ground triticale or wheat in the pellets, were fed to broiler chickens and the performance, gastro-intestinal development and health of those chickens recorded. 2. The use of whole triticale in the pelleted food produced similar bodyweight responses to when ground triticale was incorporated in the food. Food conversion efficiency was enhanced when whole triticale was used compared to ground triticale and was similar to when an exogenous enzyme was added to the ground triticale diet. The incorporation of whole wheat into the pelleted food produced similar production responses to the use of ground wheat. 3. The gastro-intestinal development of the birds was greater when they were fed the whole grain diet as gizzard weights were increased by the incorporation of whole grain into the diet. Gastro-intestinal development was thought to be related to the presence of large fibre particles in the food. 4. Proventricular dilatation and mortality due to ascites were reduced by feeding pelleted diets containing whole grain, which was possibly related to the early development of the gastro-intestinal tract relative to total body development. 5. It is suggested that the current use of exogenous enzyme additions to broiler diets may be reduced by incorporating whole grain into pelleted diets for broiler chickens.

Proneness to eating disorders: weightlifters compared to exercisers

Previous findings were confirmed suggesting that weightlifters may be more prone to eating disorders than are casual exercisers. 25 weightlifters' mean eating disorder score was significantly higher than that of 25 casual exercisers when contrasted for practical difference.

Influence of the method of calcium provision on Marek's disease losses in compound and choice fed layers

1. Two strains of layers were fed compound or choice forms of a standard diet and given calcium as either ground limestone or coarse limestone grit daily or every 2nd day. Mortality caused by Marek's disease was monitored during the rearing and laying phases. 2. A dramatic difference in Marek's disease mortality was found between the strains. Heavy Marek's disease mortality in the imported strain A in the rearing phase was not markedly affected by dietary or calcium treatment. 3. Method of feeding and calcium provision interacted to influence significantly the risk of death due to Marek's disease in the laying phase in layer strain A. 4. Choice feeding may adversely influence Marek's disease losses in layers.

U-richness is a defining feature of plant introns and may function as an intron recognition signal in maize

Using a large set of plant gene sequences we compared individual introns to their flanking exons. Both Zea mays and Arabidopsis thaliana introns are U-rich but display no apparent bias for A. We identified fifteen 11-mer U-rich motifs as frequent elements of maize introns, and these are virtually absent from exons. By mutagenesis, we show that the single U-rich motif in the Bronze2 intron of maize plays a key role in intron processing in vivo.

Reconstitution of human telomerase with the template RNA component hTR and the catalytic protein subunit hTRT

The maintenance of chromosome termini, or telomeres, requires the action of the enzyme telomerase, as conventional DNA polymerases cannot fully replicate the ends of linear molecules. Telomerase is expressed and telomere length is maintained in human germ cells and the great majority of primary human tumours. However, telomerase is not detectable in most normal somatic cells; this corresponds to the gradual telomere loss observed with each cell division. It has been proposed that telomere erosion eventually signals entry into senescence or cell crisis and that activation of telomerase is usually required for immortal cell proliferation. In addition to the human telomerase RNA component (hTR; ref. 11), TR1/TLP1 (refs 12, 13), a protein that is homologous to the p80 protein associated with the Tetrahymena enzyme, has been identified in humans. More recently, the human telomerase reverse transcriptase (hTRT; refs 15, 16), which is homologous to the reverse transcriptase (RT)-like proteins associated with the Euplotes aediculatus (Ea_p123), Saccharomyces cerevisiae (Est2p) and Schizosaccharomyces pombe (5pTrt1) telomerases, has been reported to be a telomerase protein subunit. A catalytic function has been demonstrated for Est2p in the RT-like class but not for p80 or its homologues. We now report that in vitro transcription and translation of hTRT when co-synthesized or mixed with hTR reconstitutes telomerase activity that exhibits enzymatic properties like those of the native enzyme. Single amino-acid changes in conserved telomerase-specific and RT motifs reduce or abolish activity, providing direct evidence that hTRT is the catalytic protein component of telomerase. Normal human diploid cells transiently expressing hTRT possessed telomerase activity, demonstrating that hTRT is the limiting component necessary for restoration of telomerase activity in these cells. The ability to reconstitute telomerase permits further analysis of its biochemical and biological roles in cell aging and carcinogenesis.

Kinship support and maternal and adolescent well-being in economically disadvantaged African-American families

This study tested a conceptual model developed to explain the link between kinship support and the psychological well-being of economically disadvantaged African-American adolescents. The relation of kinship support with maternal and adolescent well-being and mothers' child-rearing practices was assessed in 51 African-American families whose incomes placed them at or below the poverty threshold. Findings revealed that kinship social support to mothers/female guardians was positively associated with adolescent psychological well-being, maternal well-being, and more adequate maternal parenting practices (acceptance, firm control and monitoring of behavior, autonomy granting). Maternal well-being and more adequate maternal parenting practices were positively related to adolescent well-being. Evidence of the mediational role of maternal well-being and parenting practices was revealed. When the effects of maternal well-being and maternal parenting practices were controlled, significant relations between kinship support and adolescent well-being were no longer apparent.

Antiferromagnetism in Pressure-Amorphized Fe 2 SiO 4

Amorphous Fe(2)SiO(4) synthesized at elevated pressures exhibits a Néel transition at a temperature identical to that observed in the crystalline form, T(N) = 65 (+/-2) kelvin at zero pressure. This behavior contrasts sharply with observations on other disordered systems, such as spin glasses, which characteristically exhibit strong "frustration" of the spins and consequent marked suppression of the Néel transition.

Black and white women's attitudes toward interracial marriage

50 white women and 50 black women, US citizens between the ages 18 and 23 years, were asked to rate their attitudes about interracial marriage on a 10-point response scale. The white women were somewhat more favorable, if not significantly so, than the black women about men and women of their race marrying persons of another race. However, scorers at the extremes of the scale were significantly different. The white women tended to cluster at the scale extreme favoring interracial marriage, whereas the black women tended to cluster at the other unfavorable extreme. Implications and research needs are discussed.

Crisis intervention: long-term training effects

10 months following a crisis-intervention training program which focused on interpretation of signal events, 17 participants more frequently reported increased belief in their ability to recognize the need for intervention and to intervene effectively than did 22 control subjects. Perceived frequency of intervention by trained participants, however, had decreased rather than increased. Implications of the findings and recommendations for research are discussed.

Effect of age on congruence between adults' and youths' ratings of life event stressors

Life event stressors were rated by 60 sixth grade students from their personal points-of-view and by two adult samples (ns = 11 and 17) on the basis of how they believed a typical 12- to 14-yr.-old today would rate events. Ratings of adults and sixth grade youth indicated strong congruence and were significantly different from the rating relationship previously reported between adults and ninth grade students. Adults' familiarity with youth strengthened but did not significantly improve congruence of ratings.

A novel binding assay for phospholipase A2

We have devised a rapid and simple assay for estimating the binding of pancreatic phospholipase A2 to a bilayer lipid membrane. The binding was observed to be extremely rapid at 37 degrees and was absolutely dependent upon Ca2+. Amongst several drugs known to inhibit the catalytic activity of phospholipase only mepacrine at high concentrations (500 microM) and chlorpromazine (100 microM) were active. Treatment of the enzyme with p-bromophenacylbromide did not inhibit binding. Several alcohols potentiated binding whereas detergents tended to inhibit. Amongst several purified proteins tested, only the steroid-induced anti-phospholipase protein lipocortin prevented binding. The use of this assay in screening for antiphospholipase agents is discussed.

Double-blind comparison of half-dose and standard-dose flupenthixol decanoate in the maintenance treatment of stabilised out-patients with schizophrenia

A double-blind controlled trial of 50% dose reduction in maintenance treatment in stable out-patients with low BPRS scores and good social function shows a significantly higher relapse rate in the low-dose group at 12 months (P less than 0.05). After an interval of 24-36 months from dose reduction, 56-76% had experienced a relapse and 76-79% had resumed their former dosage. No clear advantage was shown for the lower dose in either a reduction of side-effects or improved social function, but a reduced prevalence or lower rate of symptom emergence for tardive dyskinesia was suggested.

Disulfiram as a radiation modifier

The radiation modifying effect and toxicity of tetraethylthiuram disulfide (disulfiram) have been studied. Disulfiram (DSM) inhibits aldehyde dehydrogenase, dopamine-beta-oxygenase, microsomal mixed-function oxidases and cytochrome P-450 enzymes. It is widely used for aversion therapy in alcoholism. Disulfiram also inhibits tumor formation by several known carcinogens. A biphasic toxicity pattern of DSM is reported in the L-929 mouse fibroblast culture system. Disulfiram is 100 percent toxic at 2 X 10(-7) M (0.05 micrograms per ml), 23 percent toxic at 3 X 10(-7) M (0.1 microgram per ml), and 100 percent toxic again at 3.4 X 10(-6) M (1.0 microgram per ml). The pattern is similar to the biphasic toxicity pattern of DMS's major metabolite, sodium diethyldithiocarbamate (DTC). Reports of both radiation protection and radiation enhancement by DTC exist. Previously, a radioprotective effect by 2 X 10(-6) M DTC (dose modifying factor = 1.26) has been demonstrated in the L-929 cell system. To date, no radiation modifying properties of DSM have been reported. Our investigation of DSM as a radiation modifier at 3 X 10(-7) M (0.1 microgram per ml) did not show significant improvement in survival of irradiated cells treated with DSM relative to the irradiated control group, as determined by absence of a difference in the Do of the two groups. Considering DSM's close structural relationship to DTC, it is possible that DSM may exhibit a radioprotective effect when applied in a different concentration than what was used in our research.

Rapid sample preparation and high performance liquid chromatographic determination of total and unbound serum disopyramide

A rapid sample preparation procedure, which requires no solvent extraction or concentration, for the high performance liquid chromatographic (HPLC) determination of disopyramide is described. The chromatography is performed on a C-18 radial compression mu-Bondapak column and detection by absorbance at 254 nm with a run time of 12 min. The mobile phase is 10 mM sodium acetate (pH 4.5)/acetonitrile (3:1 vol/vol). For the total drug assay, 50 microliter 30% (wt/vol) trichloroacetic acid is added to 500 microliter serum, which causes the precipitation of protein. Following centrifugation, 100 microliter of supernatant is mixed with 25 microliters of internal standard (25 micrograms/ml, ethyl p-aminobenzoate), and 50 microliters of this mixture is injected into the HPLC. Unbound disopyramide is separated from protein-bound drug by filtration with an Amicon Centrifree filter, which removes 99.6% of protein and does not retain disopyramide. To 100 microliters of this filtrate is added 25 microliters of internal standard, and 50 microliters is injected into the HPLC. The assay is linear to at least 20 micrograms/ml. The total drug assay shows an average recovery of 93.0% with an average coefficient of variation (CV) of 3.4%. The unbound drug assay shows an average CV of 4.1%. The percentage of free drug in a sample containing 4.85 g/dl protein varies from 68.0 to 83.5% at concentrations of 2.5-10 micrograms/ml, which illustrates the concentration-dependent nature of the protein binding, and the need to measure the unbound fraction of drug. Of 31 drugs tested for interference, none was found to interfere.

Expression of troponin T in atria and ventricles of avian and mammalian hearts

The expression of troponin T in atria and ventricles of adult chicken, rabbit and beef hearts has been studied by two dimensional electrophoresis of soluble extracts from these tissues. The monoclonal antibody, T1/61, has been used to detect the presence of troponin T in the chicken samples. In the chicken only one form of troponin T has been found which is resolved into two spots that probably are due to phosphorylated and non phosphorylated forms. The gels of chicken atria and ventricles are identical with the same patterns, not only of troponin T but also of tropomyosin and myosin light chains. In rabbit and beef the position of troponin T can be located by comparison with the chicken. In the beef it is possible that two forms are present but in the rabbit there appears to be only one. The gels of atria and ventricles of rabbit and beef hearts show differences only in the myosin light chains whereas the expression of tropomyosin is the same. In beef, beta-tropomyosin is found in both tissues. On the evidence of these gels there are no differences in the expression of troponin T or tropomyosin between the atria and ventricles of any of the hearts studied.

Effect of mucous glycoprotein on nucleation time of human bile

The purpose of this study was to determine whether mucous glycoprotein is the nucleating factor responsible for the rapid in vitro nucleation time of gallbladder bile from persons with cholesterol gallstones. Ultracentrifugation and ultrafiltration of abnormal bile removed all detectable mucous glycoprotein, yet bile that had been filtered exhibited as rapid a nucleation time as unfiltered bile. When abnormal bile was heated to 95 degrees C for 60 min, nucleation time was significantly prolonged. Rapid nucleation time could be restored to heated abnormal bile by addition of small volumes of unheated bile. Purified human mucous glycoprotein accelerated nucleation time of human bile, but mucous glycoprotein from control patients was as effective as that from gallstone patients. There was a direct relationship between mucous glycoprotein concentration and effect on nucleation time. Mucous glycoprotein may be important in the early stages of stone formation, but it is probably not the agent responsible for the sharp discrimination between control bile and gallbladder bile from patients with cholesterol stones found in the in vitro nucleation time test. The markedly prolonged nucleation time of heated abnormal bile is preliminary evidence that the nucleating factor may be a heat-labile protein other than mucous glycoprotein.