TNF deficiency causes alterations in the spatial organization of neurogenic zones and alters the number of microglia and neurons in the cerebral cortex

BACKGROUND

Although tumor necrosis factor (TNF) inhibitors are used to treat chronic inflammatory diseases, there is little information about how long-term inhibition of TNF affects the homeostatic functions that TNF maintains in the intact CNS.

MATERIALS AND METHODS

To assess whether developmental TNF deficiency causes alterations in the naïve CNS, we estimated the number of proliferating cells, microglia, and neurons in the developing neocortex of E13.5, P7 and adult TNF knock out (TNF^-/-) mice and wildtype (WT) littermates. We also measured changes in gene and protein expression and monoamine levels in adult WT and TNF^-/- mice. To evaluate long-term effects of TNF inhibitors, we treated healthy adult C57BL/6 mice with either saline, the selective soluble TNF inhibitor XPro1595, or the nonselective TNF inhibitor etanercept. We estimated changes in cell number and protein expression after two months of treatment. We assessed the effects of TNF deficiency on cognition by testing adult WT and TNF^-/- mice and mice treated with saline, XPro1595, or etanercept with specific behavioral tasks.

RESULTS

TNF deficiency decreased the number of proliferating cells and microglia and increased the number of neurons. At the same time, TNF deficiency decreased the expression of WNT signaling-related proteins, specifically Collagen Triple Helix Repeat Containing 1 (CTHRC1) and Frizzled receptor 6 (FZD6). In contrast to XPro1595, long-term inhibition of TNF with etanercept in adult C57BL/6 mice decreased the number of BrdU⁺ cells in the granule cell layer of the dentate gyrus. Etanercept, but not XPro1595, also impaired spatial learning and memory in the Barnes maze memory test.

CONCLUSION

TNF deficiency impacts the organization of neurogenic zones and alters the cell composition in brain. Long-term inhibition of TNF with the nonselective TNF inhibitor etanercept, but not the soluble TNF inhibitor XPro1595, decreases neurogenesis in the adult mouse hippocampus and impairs learning and memory after two months of treatment.

Efficacy of imidacloprid, imidacloprid/permethrin and phoxim for flea control in the Mustelidae (ferrets, mink)

Farmed mink (Mustela vison), a close relative of the domestic ferret (Mustela putorius furo), naturally infested with the squirrel flea (Ceratophyllus sciurorum) were included in a study to investigate three compounds for flea control. The test products were imidacloprid in a 10% (w/v) solution, an imidacloprid 10% (w/v)/permethrin 50% (w/v) solution, and phoxim; all three are well-known compounds for the control of different ectoparasites in a wide range of animals. Two groups of mink received 0.1 ml per animal of the imidacloprid or the imidacloprid/permethrin combination at days 0 and 28, respectively. Two groups of mink were sprayed with 25 ml of a 0.1% phoxim solution at day 0 and either 1x25 ml or 2x25 ml, respectively, of a 0.05% phoxim solution at day 28. One group of mink served as an untreated control. At assessment on day 56 the efficacy was 91.9% in the imidacloprid group, 89.3% in the imidacloprid/permethrin group, 92.2% in the phoxim 1x25-ml group and 99.3% in the phoxim 2x25 ml group, respectively. In the untreated control group an average of 757 fleas per mink nesting material was recorded.

Dermatological and parasitological evaluation of infestations with chewing lice (Werneckiella equi) on horses and treatment using imidacloprid

Lice infestations in horses caused by the chewing louse Werneckiella (Damalinia) equi are observed worldwide. In the present study, the efficacy of 10% imidacloprid was tested on horses naturally infested with lice. Two groups of animals received a double application of 4 ml and 8 ml Advantage 10% spot-on on day 0 and 28 either. Horses, presenting dermatological signs with negative lice counts, were also included in this investigation. 40.86% of the horses presented positive lice counts and 84.21% of these animals showed clinical dermatologic signs. 65.45% of the lice-negative horses also showed clinical manifestations. Two days after treatment, lice counts dropped in both the treatment groups and on day 56, all animals were free of alive lice, and dermatological lesions decreased significantly (P<0.001) in both the lice-positive and the negative animals. No correlation (P>0.050) between lice burden and clinical signs was detected.

Infestation of Werneckiella equi on Icelandic horses, characteristics of predilection sites and lice dermatitis

Lice infestations on horses caused by the lice Werneckiella (Damalinia) equi and Haematopinus equi are observed worldwide. In this study, the distribution and clinical manifestations of lice on Icelandic horses were examined. Thirty-eight out of 93 animals (40.86%) were identified as infested with W. equi. Sixty-eight animals (73.12%) presented dermatological lesions associated with lice infestation, while only 32 of these animals presented lice. Six animals had no clinical signs although of being lice-positive, and 19 animals (20.43%) showed neither lice nor clinical manifestations. Lice burdens varied from animal to animal, and clinical manifestations occurred at all levels of infestation. Focal alopecia was the main clinical sign (83.78%) on lice-positive horses, while scaling and crusts occurred in 10.81% and 9.68% of the cases, respectively. Clinical signs present in the head and the neck/mane area were found to be an indication of lice infestation in horses.

Natural infestation of the chewing lice (Werneckiella equi) on horses and treatment with imidacloprid and phoxim

Infestation with the chewing louse (Werneckiella (Damalinia) equi) can be found on horses world-wide. Louse infestations, including clinical signs of louse-derived dermatitis, are known from Icelandic horses. A clinical field investigation was conducted in Iceland using horses with natural louse infestations to evaluate the efficacy of imidacloprid in a 10% solution in comparison with phoxim in a 0.05% solution. A total of 27 horses received a single imidacloprid treatment using 16 ml of the 10% solution along the mane and on the dorso-lateral trunk. A further 43 horses were treated twice, 14 days apart, with phoxim, using 2 x 50 ml solution applied along the mane and the dorso-lateral trunk. At the final evaluation on day 28, complete control of the lice was obtained for the imidacloprid treated horses and only a single moribund louse was found on two horses treated with phoxim.

Host location, survival and fecundity of the Oriental rat flea Xenopsylla cheopis (Siphonaptera: Pulicidae) in relation to black rat Rattus rattus (Rodentia: Muridae) host age and sex

Host choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25 degrees C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat's presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50-70% decline in the initial number of adult fleas during the first week after their release onto a rat host, and this decline was greatest on juvenile rats. Flea fecundity was also significantly lower on juvenile rat hosts but no differences due to the sex of the rat were observed. This experimental study supports the hypothesis that differences in flea count due to host sex, reported in field surveys, result from sexual differences in host behaviour and not from discriminatory host-seeking behaviour by X. cheopis. Differences in flea count due to host age may be affected by differences in X. cheopis fecundity, which may itself be mediated by host behaviour such as grooming.

Palatability and toxicity of fipronil as a systemic insecticide in a bromadiolone rodenticide bait for rat and flea control

Vector control in plague-infested areas requires a simultaneous killing of rodents and their fleas. We investigated the efficacy of a combination of a systemic insecticide, fipronil, in a rodenticide bait formulation under laboratory conditions. Four different concentrations of fipronil (0.05%, 0.005%, 0.0005% with acetone as a solvent, and 0.05% with propylene glycol as a solvent) and two controls (solvents only) were combined with the rodenticide bait (crushed organically grown wheat with 0.005% bromadiolone). Each concentration was offered together with an untreated non-poisonous challenge bait to 10 singly caged Rattus rattus L., each with 100 rat fleas Xenopsylla cheopis Rothschild (Siphonaptera: Pulicidae) in the nest. Treated bait consumption was relatively low and an unsatisfactory rat mortality of around 50% only was obtained in all tests. The palatability of the bait, however, was not affected by the fipronil concentration. Even at the lowest fipronil concentration, average flea mortality was still above 95%, and doses of more than I mg fipronil per kg rat body weight gave a nearly complete kill of fleas. Fipronil can be highly effective as a systemic insecticide to for flea control, provided that a more attractive bait base for roof rats is used.

A circadian rhythm of locomotor activity in newly emerged Ceratophyllus sciurorum

Circadian rhythm in newly emerged individuals of the Red Squirrel (Scuirus vulgaris) flea C.s.sciurorum was studied in a constant environment, using an insect activity monitor. Trials were run over 7 days using two start times (08.00 and 17.00 hours). The results show that, regardless of start time, the fleas display a 24 h activity rhythm. The presence of a rhythm under constant conditions gives a strong indication that C.s.sciurorum has a self-sustaining clock which is started by disturbance and is most likely to be linked to host activity patterns.

Coordination dynamics of biological zinc "clusters" in metallothioneins and in the DNA-binding domain of the transcription factor Gal4

The almost universal appreciation for the importance of zinc in metabolism has been offset by the considerable uncertainty regarding the proteins that store and distribute cellular zinc. We propose that some zinc proteins with so-called zinc cluster motifs have a central role in zinc distribution, since they exhibit the rather exquisite properties of binding zinc tightly while remaining remarkably reactive as zinc donors. We have used zinc isotope exchange both to probe the coordination dynamics of zinc clusters in metallothionein, the small protein that has the highest known zinc content, and to investigate the potential function of zinc clusters in cellular zinc distribution. When mixed and incubated, metallothionein isoproteins-1 and -2 rapidly exchange zinc, as demonstrated by fast chromatographic separation and radiometric analysis. Exchange kinetics exhibit two distinct phases (k(fast) approximately 5000 min(-1) x M(-1); k(slow) approximately 200 min(-1) x M(-1), pH 8.6, 25 degrees C) that are thought to reflect exchange between the three-zinc clusters and between the four-zinc clusters, respectively. Moreover, we have observed and examined zinc exchange between metallothionein-2 and the Gal4 protein (k approximately 800 min(-1) x M(-1), pH 8.0, 25 degrees C), which is a prototype of transcription factors with a two-zinc cluster. This reaction constitutes the first experimental example of intermolecular zinc exchange between heterologous proteins. Such kinetic reactivity distinguishes zinc in biological clusters from zinc in the coordination environment of zinc enzymes, where the metal does not exchange over several days with free zinc in solution. The molecular organization of these clusters allows zinc exchange to proceed through a ligand exchange mechanism, involving molecular contact between the reactants.

D-Phe complexes of zinc and cobalt carboxypeptidase A

The binding of D-phenylalanine, D-Phe, to both zinc and cobalt carboxypeptidase A, ZnCPD and CoCPD, has been investigated by a combination of kinetic and spectroscopic techniques. Kinetic studies of the ZnCPD catalyzed hydrolysis of dansyl-Gly-Ala-L-Phe indicate that D-Phe inhibition occurs through a two-site sequential competitive inhibition mode with Ki values of 45 microM and 11.6 mM at pH 8.4, 1 M NaCl, 25 degrees C. Spectral titration of CoCPD under the same conditions indicates a very strong binding mode of D-Phe (KD < 100 microM) that only slightly perturbs the visible cobalt electronic transitions. However, the conversion of CoCPD.D-Phe into a CoCPD.D-Phe2 (KD, 1.13 mM) is accompanied by a very strong spectral perturbation resulting in a complex that is characterized by Amax values of 506 nm (epsilon = 27 M-1 cm-1) and 605 nm (epsilon = 17 M-1 cm-1) and a shoulder at 530 nm (epsilon = 23 M-1 cm-1). The spectral properties of this ternary complex differ markedly from that of the CoCPD.L-Phe.N3-ternary complex. X-ray absorption fine structure, XAFS, studies indicate that these differences are likely due to a more regular tetrahedral coordination sphere for the ternary azide complexes compared to an octahedral coordination geometry for the Zn and CoCPD.D-Phe2 complexes.

X-ray absorption fine structure study of the active site of zinc and cobalt carboxypeptidase A in their solution and crystalline forms

A comparative study on the metal environment of Zn(II)-carboxypeptidase A (ZnCPD) and Co(II)-carboxypeptidase A (CoCPD) in their solution and crystalline forms using the X-ray absorption fine structure (XAFS) technique has been conducted. The first coordination sphere of Zn for ZnCPD in its solution state is found to consist of two distributions of atoms, with four atoms (N or O) located at an average distance of 2.03 +/- 0.01 A and one atom (N or O) located at 2.57 +/- 0.04 A. The four-atom distribution remains the same for ZnCPD in its crystalline state, but the fifth atom is found at 2.36 +/- 0.04 A. Examination of the higher coordination shell, between 2.7 and 4.2 A, reveals the presence of two imidazoles. Combined with X-ray crystallographic results, a structural model is proposed. The four atoms at an average distance of 2.03 A are assigned to the two delta 1 nitrogens of His-69 and His-196, one epsilon 1 oxygen of Glu-72, and the oxygen of a coordinated water molecule. The atom at 2.57 A for ZnCPD in solution is assigned to the epsilon 2 oxygen of Glu-72. The results for CoCPD in solution are similar with the four atoms at an average distance of 2.08 +/- 0.01 A and one atom at 2.50 +/- 0.04 A, which moves to 2.34 +/- 0.04 A in the crystalline enzyme. The intensity of the 3d "pip" peak for CoCPD is consistent with a distorted tetragonal metal geometry for the solution form of the enzyme which is converted to a more pentacoordinated metal site for the crystalline enzyme. The first shell distribution of crystalline CoCPD is quite disordered, which may be largely due to the disorder of His-69 and His-196 as indicated by higher shell analysis. Thus, the XAFS studies show that the metal coordination spheres in the zinc and cobalt enzymes are quite similar in the solution state but differ from their crystalline counterparts. The XAFS studies provide the necessary background for measurement of substrate- and inhibitor-promoted structural changes in the metal coordination sphere of the zinc and other metal-substituted carboxypeptidases in the solution state.

Characterization of an inhibitory metal binding site in carboxypeptidase A

The specificity of metal ion inhibition of bovine carboxypeptidase A ([(CPD)Zn]) catalysis is examined under stopped-flow conditions with use of the fluorescent peptide substrate Dns-Gly-Ala-Phe. The enzyme is inhibited competitively by Zn(II), Pb(II), and Cd(II) with apparent KI values of 2.4 x 10(-5), 4.8 x 10(-5), and 1.1 x 10(-2) M in 0.5 M NaCl at pH 7.5 and 25 degrees C. The kcat/Km value, 7.3 x 10(6) M-1 s-1, is affected less than 10% at 1 x 10(-4) M Mn(II) or Cu(II) and at 1 x 10(-2) M Co(II), Ni(II), Hg(II), or Pt(IV). Zn(II) and Pb(II) are mutually exclusive inhibitors. Previous studies of the pH dependence of Zn(II) inhibition [Larsen, K. S., & Auld, D. S. (1989) Biochemistry 28, 9620] indicated that [(CPD)Zn] is selectively inhibited by a zinc monohydroxide complex, ZnOH+, and that ionization of a ligand, LH, in the enzyme's inhibitory site (pKLH 5.8) is obligatory for its binding. The present study allows further definition of this inhibitory zinc site. The ionizable ligand (LH) is assigned to Glu-270, since specific chemical modification of this residue decreases the binding affinity of [(CPD)Zn] for Zn(II) and Pb(II) by more than 60- and 200-fold, respectively. A bridging interaction between the Glu-270-coordinated metal hydroxide and the catalytic metal ion is implicated from the ability of Zn(II) and Pb(II) to induce a perturbation in the electronic absorption spectrum of cobalt carboxypeptidase A ([(CPD)Co]).(ABSTRACT TRUNCATED AT 250 WORDS)

Catalytic and conformational changes induced by limited subtilisin cleavage of bovine carboxypeptidase A

Limited proteolysis of carboxypeptidase A from bovine pancreas with subtilisin Carlsberg generates a stable intermediate, carboxypeptidase S, whose esterase and peptidase activities are increased and decreased, respectively, under standard assay conditions. Carboxypeptidase S was isolated by affinity chromatography. Sequence analysis shows that it is cleaved solely at the Ala154-Gly155 bond. Its enzymatic properties were determined under stopped-flow conditions with Dns-Gly-Ala-Phe and its ester analogue Dns-Gly-Ala-OPhe. For both substrates, the Km values are increased 30-40-fold. The kcat value for peptide hydrolysis is virtually unaffected whereas that for ester hydrolysis is increased 10-fold. The magnitude of the Km effect is equivalent to a loss of 9 kJ/mol of binding energy and likely reflects a disruption of the network of hydrogen bonds that links Tyr-248 and Arg-145 to the backbone carbonyls of Ala-154 and Gly-155. The difference in kcat effects for the two substrate classes is related to differences in the chemical nature of the rate-determining step. Product release is rate determining for catalytic hydrolysis of ester substrates, and hence, the increase in kcat indicates that dissociation of products is facilitated as a result of the Ala154-Gly155 bond scission. The changes in enzymatic activity accompanying limited proteolysis are due to conformational alterations in the vicinity of the active center of the molecule. The affinity of a monoclonal antibody, mAb 100, directed toward the antigenic determinant located between residues 209 and 218 in carboxypeptidase A is diminished considerably for carboxypeptidase S.(ABSTRACT TRUNCATED AT 250 WORDS)

Authoritarianism and attitudes toward AIDS victims

This study investigated the relationship of authoritarianism and attitudes toward AIDS victims in three samples. One hundred fifty-eight students at Oregon State University participated, including 101 students from the United States, 25 from Japan, and 32 from other Asian societies. The survey instrument included the 20-item Attitudes Toward AIDS Victims (ATAV) Scale, the 18-item F Scale, the Form A, and 14-item Formal Content of Dogmatism Scale. Results showed slight but significant correlations between the ATAV and F (r = .17, p less than .044) and Formal Content of Dogmatism (r = .20, p less than .023) Scales for the United States sample. Highly significant differences were found in the predicted direction among the three samples on authoritarianism, F = 43.94, p less than .001.

Carboxypeptidase A: mechanism of zinc inhibition

Zinc ions competitively inhibit carboxypeptidase A from bovine pancreas. The state(s) of hydroxylation of zinc and their possible site(s) of interaction with the enzyme have been investigated by determining the strength of zinc inhibition over pH range 4.6-10.5. The inhibition kinetics were recorded under stopped-flow conditions using the alpha-Val isozyme and the peptide substrate Dns-Gly-Ala-Phe in 0.5 M NaCl at 25 degrees C. The pH dependence of pKI follows a pattern which indicates that the enzyme is selectively inhibited by zinc monohydroxide, ZnOH+ (KI = 7.1 X 10(-7) M). The formation of the inhibitory ZnOH+ complex from fully hydrated Zn2+ is characterized by an ionization constant of 9.05, and the consecutive conversion of ZnOH+ to Zn(OH)2, Zn(OH)3-, and Zn(OH)4(2-) complexes takes place with ionization constants of 9.75, 10.1, and 10.5, respectively. Ionization of a ligand, LH, in the enzyme's inhibitory site (pKLH 5.8) is obligatory for binding of the ZnOH+ complex. The enzymatic activity (kcat/Km) is influenced by three ionizable groups: pKEH2 5.78, pKEH 8.60, and pKE 10.2. Since the values of pKLH and pKEH2 are virtually identical, it is possible that the inhibitory ZnOH+ complex interacts with the group responsible for pKEH2. Previous studies have suggested that pKEH2 reflects the ionization of Glu-270 and its interaction with a water molecule coordinated to the catalytic zinc ion. It is proposed that the inhibitory zinc ion binds to the carboxylate of Glu-270 and that the inhibition process is specific for zinc monohydroxide because it allows the formation of a stabilizing hydroxide bridge between the inhibitory and catalytic zinc ions.

The Psychological Screening Inventory as a predictor of predisposition to suicide among patients at the Oregon State Hospital

Examined all closed patient files for the inclusion of scores from the Psychological Screening Inventory (PSI) at the Oregon State Hospital between 1977-1979. Subsequently, the patient files (N = 123) were assessed for suicidal inclination employing five categories, which ranged from "no suicidal ideation" to "serious attempt." t-tests were completed between Ss placed in category 1 (no suicidal ideation) and remaining categories. Results yielded a significant value for "discomfort," with lower discomfort scores related to higher suicide risks. Subsequent extreme group analysis yielded significant but opposite results for males and females, which suggests the importance of evaluating the results of the PSI separately for sex.

Attitudes toward death: a desensitization hypothesis

Attitudes toward death is a subject largely overlooked by psychology. This article reports on the development of a Likert-type scale measuring attitude toward death. Item analysis produced 32 items, with a corrected split-half reliability coefficient of .92. The scale did not predict differences between donors and professors and did not relate to age, sex, or self-esteem. It did, however, correlate negatively with religiosity, level of education, and positively with exposure to deaths of non-intimate persons. The results suggest that positive attitudes toward death are indicated by a non-religious outlook, low investment in self-relevant goals, and exposure to non-intimate (and less traumatic) deaths.

Emotional responses to frustration of approval seeking and personal identity

Several emotional responses may be made to frustration depending on the type of goal frustrated. Two types of broad goals are approval and personal identity seeking. 32 male and 38 female undergraduates participated in this role-playing study. 43 Ss were oriented toward approval seeking and 27 Ss were oriented toward personal identity. Sadness was a more dominant response (104 responses) than anger (34 responses) for high approval-seeking Ss. Approval-seeking Ss also showed more rejection of other groups on the Bogardus social-distance scale. For such Ss the inhibiting effects of approval seeking may lead to the displacement of anger toward potential outgroups.

Dogmatism and sociometric status as determinants of interaction in a small group

This study investigated the correlations between dogmatism and sociometric status as predictors of interaction in a small group ( n = 14). Results showed a positive correlation between sociometric status and various indexes of interaction and a negative correlation between dogmatism and sociometric status. The expected correlation between dogmatism and interactions did not appear.

Authoritarian traits as predictors of candidate preference in 1968 United States presidential election

The literature on the relationship of authoritarianism and political behavior is complex. This study investigated the relation of candidate preference during the 1968 presidential election to scores on 4 measures of authoritarianism. A survey was administered to a random sample of 141 male and 141 female undergraduates. Significant differences between Wallace supporters and supporters of other candidates on 3 of the 4 measures indicate that general authoritarianism, in addition to right-wing authoritarianism, is predictive of candidate preference. Sex differences were reported on only one of the 4 assessments, and age correlated inversely with all measures.

Social position, social desirability and self-esteem

Welfare clients occupy a position of low desirability, whereas college students, by reason of familial ties or prospective future contribution, occupy a position of high desirability. Significant differences were obtained between these two groups on self-esteem and length of time on welfare was a significant factor in welfare clients' self-esteem.

Authoritarianism, self esteem and insecurity

The traits underlying the authoritarian syndrome suggest that high-authoritarian Ss are insecure and low in self esteem. The present study investigated this hypothesis employing several independent assessments of self esteem. Results tended to confirm this hypothesis but showed only moderate relationships among the several measures of self esteem.

Leadership, group activity and sociometric choice in service sororities and fraternities

Task and socio-emotional functions are specialized in many groups. The critical variable seems to be the extent to which the task goals are salient to all group members and consequently viewed as legitimate. The tasks in service fraternities and sororities are likely to be accepted by all members, since a condition for membership is a desire to serve. This study investigated the task and socio-emotional functions in eight such fraternities and sororities (N of 169). Significant correlations obtained between sociometric choice for real leader and actual leadership, between sociometric choice for real leader and best-liked person, and between best-liked person and assessment of task activity. Results suggest that role differentiation is a function of task legitimacy and consequently the legitimacy of leadership itself.

Authoritarianism and attitudes toward police

A questionnaire composed of an authoritarian measure and two assessments of attitudes toward police was administered to 103 Ss. Large positive correlations obtained between authoritarianism and attitudes toward police. This relationship may be partially explained as a function of high authoritarian S's insecurity, as a result of which the police become a mediating force in an otherwise threatening environment. No sex differences were observed, but age was correlated inversely with both authoritarianism and attitudes toward police.