Intracellular survival and multiplication of Toxoplasma gondii in astrocytes

Primary neonatal murine astrocyte cultures were used to investigate the role of these glial cells in host defense of the central nervous system (CNS) against Toxoplasma gondii. For comparison, neonatal murine microglial cells were also studied. Microscopic analyses revealed that uptake of T. gondii into astrocytes was parasite-driven and was followed by uniform intracellular survival and multiplication of tachyzoites. Treatment of astrocytes with interferon (IFN)-gamma and lipopolysaccharide (LPS) had no apparent effect on the survival or growth of T. gondii. Microglia, on the other hand, had both an intrinsic phagocytosis-associated antitoxoplasma activity and a nitric oxide-dependent inhibitory activity that was up-regulated by IFN-gamma and LPS. The results of this study suggest that in contrast to microglial cells, astrocytes may provide a safe harbor within the CNS for T. gondii.

Sequence variation in the androgen receptor gene is not a common determinant of male sexual orientation

To test the hypothesis that DNA sequence variation in the androgen receptor gene plays a causal role in the development of male sexual orientation, we have (1) measured the degree of concordance of androgen receptor alleles in 36 pairs of homosexual brothers, (2) compared the lengths of polyglutamine and polyglycine tracts in the amino-terminal domain of the androgen receptor in a sample of 197 homosexual males and 213 unselected subjects, and (3) screened the the entire androgen receptor coding region for sequence variation by PCR and denaturing gradient-gel electrophoresis (DGGE) and/or single-strand conformation polymorphism analysis in 20 homosexual males with homosexual or bisexual brothers and one homosexual male with no homosexual brothers, and screened the amino-terminal domain of the receptor for sequence variation in an additional 44 homosexual males, 37 of whom had one or more first- or second-degree male relatives who were either homosexual or bisexual. These analyses show that (1) homosexual brothers are as likely to be discordant as concordant for androgen receptor alleles; (2) there are no large-scale differences between the distributions of polyglycine or polyglutamine tract lengths in the homosexual and control groups; and (3) coding region sequence variation is not commonly found within the androgen receptor gene of homosexual men. The DGGE screen identified two rare amino acid substitutions, ser205-to-arg and glu793-to-asp, the biological significance of which is unknown.

Distinct heme active-site structure in lactoperoxidase revealed by resonance Raman spectroscopy

Low-frequency resonance Raman spectra of the cyanide and carbon monoxide adducts of lactoperoxidase are obtained with Soret excitation. The nu(Fe-CN) and delta(Fe-C-N) modes are detected at 360 and 453 cm-1, respectively. Upon the isotopic substitution of 13C14N, 12C15N, and 13C15N, the band at 453 cm-1 in the natural abundance adduct shifts to 448, 452, and 445 cm-1, while the 360-cm-1 peak shifts to 358, 357, and 356 cm-1, respectively. The 360-cm-1 band is shifted to 355 cm-1 when the pH is changed from 7.0 to 10.5. On the basis of a previous normal-mode analysis of the cyanoferric adduct of myeloperoxidase, a bent Fe-C-N linkage is suggested for the cyanide adduct of lactoperoxidase. The nu(Fe-CN) (374 cm-1) and delta(Fe-C-N) (480 cm-1) modes are observed for the cyanide adduct of reduced lactoperoxidase. For the carbon monoxide adduct, the nu(Fe-CO) (533 cm-1) and delta(Fe-C-O) (578 cm-1) modes at pH 7.0 are observed to shift to 498 and 570 cm-1 as the pH is raised from 7.0 to 10.0. The strong intensity of delta(Fe-C-O) at both acid and alkaline pHs, along with a suggested bent structure of the Fe-C-N moiety, implies a narrow heme pocket for lactoperoxidase.

Chinese hyper-susceptibility to vection-induced motion sickness

Little is known about the factors that control individual differences in susceptible to motion sickness. A serendipitous observation in our laboratory that most Chinese subjects become motion sick prompted this study. We used a rotating optokinetic drum to provoke motion sickness and compared gastric responses and symptom reports of Chinese, European-American, and African-American subjects. There was no difference in the responses of European-American and African-American subjects; however, Chinese subjects showed significantly greater disturbances in gastric activity and reported significantly more severe symptoms. We suggest that this hyper-susceptibility presents a natural model for the study of physiological mechanisms of nausea and other symptoms of motion sickness.

Neuroprotective role of IL-4 against activated microglia

Microglia have been proposed to play a pathogenetic role in immunologically mediated neurodegenerative diseases. In our study, using microglial/neuronal cell cocultures primed with IFN-gamma, we found that both LPS and TNF-alpha triggered neuronal cell injury (impairment of gamma-aminobutyric acid uptake and neuronal loss) via a nitric oxide mechanism. Pretreatment of cell cocultures with IL-4, an immunosuppressive cytokine, prevented, in a dose-dependent manner, neuronal cell injury induced by activated microglia. The mechanism by which IL-4 exerts its neuroprotective effect was found to involve the inhibition of IFN-gamma priming of microglia with a subsequent decrease in the production of TNF-alpha and nitric oxide.

Neuroprotective role of IL-4 against activated microglia

Microglia have been proposed to play a pathogenetic role in immunologically mediated neurodegenerative diseases. In our study, using microglial/neuronal cell cocultures primed with IFN-gamma, we found that both LPS and TNF-alpha triggered neuronal cell injury (impairment of gamma-aminobutyric acid uptake and neuronal loss) via a nitric oxide mechanism. Pretreatment of cell cocultures with IL-4, an immunosuppressive cytokine, prevented, in a dose-dependent manner, neuronal cell injury induced by activated microglia. The mechanism by which IL-4 exerts its neuroprotective effect was found to involve the inhibition of IFN-gamma priming of microglia with a subsequent decrease in the production of TNF-alpha and nitric oxide.

A linkage between DNA markers on the X chromosome and male sexual orientation

The role of genetics in male sexual orientation was investigated by pedigree and linkage analyses on 114 families of homosexual men. Increased rates of same-sex orientation were found in the maternal uncles and male cousins of these subjects, but not in their fathers or paternal relatives, suggesting the possibility of sex-linked transmission in a portion of the population. DNA linkage analysis of a selected group of 40 families in which there were two gay brothers and no indication of nonmaternal transmission revealed a correlation between homosexual orientation and the inheritance of polymorphic markers on the X chromosome in approximately 64 percent of the sib-pairs tested. The linkage to markers on Xq28, the subtelomeric region of the long arm of the sex chromosome, had a multipoint lod score of 4.0 (P = 10(-5), indicating a statistical confidence level of more than 99 percent that at least one subtype of male sexual orientation is genetically influenced.

A multivariate analysis of the relationship between work ability and S. japonicum infection in Dongting Lake region, in China

A cross-sectional case-control study on the association between the reduced work ability and S. japonicum infection was carried out in a moderate endemic area for schistosomiasis japonica in the southern part of Dongting lake in China. A total of 120 cases with reduced work ability and 240 controls paired to the case by age, sex, occupation and without reduced work ability, participated in the study. The mean age for individuals was 37.6 years old (21-60), the ratio of male:female was 60:40, the prevalence of S. japonicum in the individuals was 28.3%. The results obtained in this study showed that the infection of S. japonicum in case and control groups was 49.2% (59/120) and 17.9% (43/240), respectively. Odds ratio for reduced work ability among those who had schistosomiasis was 4.34 (95%), confidence interval was 2.58-7.34, and among those who had S. japonicum infection (egg per gram > 100) was up to 12.67 (95%), confidence interval was 3.64-46.39. After odds ratio was adjusted by multiple logistic regression, it was confirmed that heavier intensity of S. japonicum infection and splenomegaly due to S. japonicum infection were the main risk factors for reduced work ability in the population studied.

[Effect of superoxide dismutase on experimental allergic uveitis]

In this study, experimental allergic uveitis (EAU) in guinea pigs was induced by an injection of bovine serum albumin (BSA) into the vitreous after having pre-immunized them intradermally with BSA plus incomplete Freund adjuvant, and the effect of superoxide dismutase (SOD) on EAU was observed. The result showed that, histopathologically, the phlogistic cell infiltration and exudation within the anterior ocular part of the SOD- treated animals reduced notably. It is suggested that SOD which can scavenge the free radical superoxide anion may alleviate the cellular reaction in the pathological process of uveitis.

Hemodynamic and nonhemodynamic mechanisms of experimental pulmonary edema in rats and the effect of anisodamine and tetramethylpyrazine. Part 1: Survival rate, pulmonary index, pathological change and pulmonary vascular permeability

Pulmonary edema (PE) which is similar to the neurogenic type was induced by adrenaline (AD) administration (0.1 mg/kg) in rats. Acute progressive respiratory distress, cyanosis and dyspnea occurred. All the experimental animals in the PE group died within 20 min after AD injection, with a pulmonary index (PI) of 1.70 +/- 0.47 (mean +/- S) which was much higher than that in the normal group. The mortality rate was 100%. It was found that in rats with PE, a protein-rich fluid filled the alveolar and interstitial spaces, and ecchymosis occurred. The capillary permeability as estimated by Evans blue injection showed that Evans blue from extraction fluid and bronchoalveolar lavage (BAL) in the PE rats was at a much higher level than that in the normal control (NC) rats. In anisodamine (ADM, 654-2) and tetramethylpyrazine (TMP) treated rats, almost all the damage was diminished or absent, and the mortality rates were decreased from 100% to 4.4% and 20%, respectively. 654-2 and TMP could significantly inhibit the increase of pulmonary permeability.

Glycosidase digestion, electrophoresis and chromatographic analysis of recombinant human granulocyte colony-stimulating factor glycoforms produced in Chinese hamster ovary cells

Recombinant human granulocyte colony stimulating factor (G-CSF) produced in Chinese hamster ovary cells is glycosylated. The carbohydrate compositional analysis indicated that G-CSF molecule contains sialic acid, galactose and galactosamine. By isolation and characterization of the purified glycopeptides obtained from cleavages by Staphylococcal aureus V-8 protease and cyanogen bromide, the O-linked glycosylation site was confirmed to be a Thr residue at position 133. Neuraminidase and O-glycanase digestion followed by sodium dodecyl sulfate polyacrylamide and isoelectric focusing gel electrophoreses distinguished two possible carbohydrate structures attached at Thr-133: structure A, NeuNAc-Gal-beta(1,3)-GalNAc-O-Thr; and structure B, NeuNAc-Gal-beta(1,3)-[NeuNAc]-GalNAc-O-Thr. Different glycoforms, undigested or after glycosidase digestion, can also be separated by ion-exchange or reversed-phase high-performance liquid chromatography. The approach described in this report provides a simple and valuable procedure to characterize glycoprotein structures containing simple carbohydrate moieties.

Activated microglia inhibit multiplication of Toxoplasma gondii via a nitric oxide mechanism

The role of microglia in host defense against Toxoplasma gondii is unknown. In the present study, we investigated the multiplication of T. gondii tachyzoites in murine microglial cell cultures. T. gondii multiplied readily in these cells; multiplication was prevented when microglia were activated with interferon-gamma plus lipopolysaccharide, a treatment that also upregulates nitric oxide (NO) synthase activity. Simultaneous treatment of microglial cell cultures with activation signals and the NO synthase inhibitor NG-monomethyl-L-arginine (NGMA) prevented the antitoxoplasmic activity. Transmission electron microscopic analysis demonstrated degenerative tachyzoites in activated microglia but not in control or NGMA groups. These findings support the view that the host defense function of activated microglia against T. gondii involves generation of the free radical NO.

Effects of cytokines on multiplication of Toxoplasma gondii in microglial cells

Microglia may play a role in host defense against Toxoplasma gondii in the central nervous system. In our study, the antitoxoplasma activity of murine microglia was investigated. T. gondii multiplied readily in cultured microglial cells, and activation of these cells with IFN-gamma plus LPS suppressed (p < 0.01) intracellular growth of this parasite. This antitoxoplasma defense of activated microglia was significantly blocked by neutralizing antibodies against TNF-alpha and transforming growth factor-beta, suggesting that these cytokines play a role in the inhibitory process. Consistent with this hypothesis, activation of microglia with IFN-gamma plus TNF-alpha or transforming growth factor-beta inhibited, in a dose-dependent manner, T. gondii multiplication. Treatment with pentoxifylline or dexamethasone, drugs that suppress production of TNF-alpha, prevented (p < 0.01) the microglia from exerting an anti-T. gondii effect. These findings suggest that the host defense function of microglia against T. gondii is dependent primarily on the activating properties of IFN-gamma and TNF-alpha, and that agents that interfere with cytokine-mediated activation may promote the pathogenesis of this infection.

Effects of cytokines on multiplication of Toxoplasma gondii in microglial cells

Microglia may play a role in host defense against Toxoplasma gondii in the central nervous system. In our study, the antitoxoplasma activity of murine microglia was investigated. T. gondii multiplied readily in cultured microglial cells, and activation of these cells with IFN-gamma plus LPS suppressed (p &lt; 0.01) intracellular growth of this parasite. This antitoxoplasma defense of activated microglia was significantly blocked by neutralizing antibodies against TNF-alpha and transforming growth factor-beta, suggesting that these cytokines play a role in the inhibitory process. Consistent with this hypothesis, activation of microglia with IFN-gamma plus TNF-alpha or transforming growth factor-beta inhibited, in a dose-dependent manner, T. gondii multiplication. Treatment with pentoxifylline or dexamethasone, drugs that suppress production of TNF-alpha, prevented (p &lt; 0.01) the microglia from exerting an anti-T. gondii effect. These findings suggest that the host defense function of microglia against T. gondii is dependent primarily on the activating properties of IFN-gamma and TNF-alpha, and that agents that interfere with cytokine-mediated activation may promote the pathogenesis of this infection.

Identification of a chemotactic domain of the pro-inflammatory S100 protein CP-10

We previously reported the purification and partial amino acid sequence of a novel murine cytokine designated CP-10, which has chemotactic activity for murine polymorphonuclear cells (PMN) and macrophages. The complete cDNA encoding an 88-amino acid polypeptide has been isolated and the sequence is presented here. Transient transfection of CP-10 cDNA into CV-1 cells confirmed the chemotactic activity of rCP-10 for murine PMN. CP-10 has sequence homology with members of the S100 family of Ca(2+)-binding proteins with pronounced amino acid sequence similarities within the putative N- and C-terminal Ca(2+)-binding sites, but differences within their connecting hinge and C-terminal regions. We have confirmed the hypothesis of Kligman and Hilt that functional specificity of individual members of the S100 protein family may reside in the hinge region. A synthetic peptide corresponding to the hinge region of CP-10 (CP-10(42-55) was compared with native CP-10 in chemotaxis and skin test assays. Native CP-10 had potent activity for phagocytic cells, but not lymphocytes, in vitro (optimal activity, 10(-11) to 10(-13) M) and elicited a sustained recruitment of neutrophils and mononuclear cells over 24 h in vivo. The hinge-region peptide had strong chemotactic activity for murine phagocytic cells (optimal activity, 10(-10) - 10(-11) M) but elicited only a transient infiltration of neutrophils over 4 to 8 h after intradermal injection. Results indicate that although the hinge region contributes significantly to the functional specificity of the S100 protein CP-10, sustained cellular recruitment typical of a delayed type hypersensitivity response is apparently dependent on the structural integrity of the protein.

Morphine inhibits the release of tumor necrosis factor in human peripheral blood mononuclear cell cultures

Opiates modulate a variety of immune responses of peripheral blood mononuclear cells (PBMC). When PBMC were treated with morphine for 24 h, cells released less (P < 0.05) bioactive TNF, a cytokine important in host defense, in the following 24-h incubation period when stimulated with lipopolysaccharide and phytohemagglutinin. Morphine alone did not significantly alter the release of TNF from PBMC cultures. Pretreatment of PBMC cultures for 1 h with naloxone blocked (P < 0.05) the inhibitory effect of morphine on the release of TNF upon stimulation with phytohemagglutinin, but not with lipopolysaccharide, suggesting the involvement of an opioid receptor. The mechanism of morphine-induced suppression of TNF release appears to be counteracted by the effect of this opiate on the release of transforming growth factor (TGF)-beta, since antibodies to this immunoregulatory cytokine further enhanced morphine-related inhibition of TNF release. Taken together, these findings indicate that morphine suppresses the release of bioactive TNF from PBMC and that TGF-beta plays a modulatory role in this inhibitory process.

Recombinant human transforming growth factor-beta 1: expression by Chinese hamster ovary cells, isolation, and characterization

A partial cDNA clone encoding the gene for human transforming growth factor-beta 1 (TGF-beta 1) was isolated from a human bladder carcinoma cell line (5637) cDNA library. Following restriction enzyme processing and ligation of synthetic oligonucleotide linkers, the gene was inserted into a plasmid and transfected into Chinese hamster ovary cells. Clonal selection and growth conditions resulted in a method for production of recombinant human TGF-beta 1 at 7 mg/liter in conditioned cell medium. Through a combination of low pH treatment, cation-exchange chromatography, and salt precipitation, the recombinant human TGF-beta 1 was purified in milligram amounts to > 95% purity in a yield of about 36%. Purification to homogeneity was accomplished by chromatography on C18 silica gel. Amino acid analysis, N-terminal sequencing, and growth inhibition assays indicate identity with the molecule from human platelets.

Identification of a chemotactic domain of the pro-inflammatory S100 protein CP-10

We previously reported the purification and partial amino acid sequence of a novel murine cytokine designated CP-10, which has chemotactic activity for murine polymorphonuclear cells (PMN) and macrophages. The complete cDNA encoding an 88-amino acid polypeptide has been isolated and the sequence is presented here. Transient transfection of CP-10 cDNA into CV-1 cells confirmed the chemotactic activity of rCP-10 for murine PMN. CP-10 has sequence homology with members of the S100 family of Ca(2+)-binding proteins with pronounced amino acid sequence similarities within the putative N- and C-terminal Ca(2+)-binding sites, but differences within their connecting hinge and C-terminal regions. We have confirmed the hypothesis of Kligman and Hilt that functional specificity of individual members of the S100 protein family may reside in the hinge region. A synthetic peptide corresponding to the hinge region of CP-10 (CP-10(42-55) was compared with native CP-10 in chemotaxis and skin test assays. Native CP-10 had potent activity for phagocytic cells, but not lymphocytes, in vitro (optimal activity, 10(-11) to 10(-13) M) and elicited a sustained recruitment of neutrophils and mononuclear cells over 24 h in vivo. The hinge-region peptide had strong chemotactic activity for murine phagocytic cells (optimal activity, 10(-10) - 10(-11) M) but elicited only a transient infiltration of neutrophils over 4 to 8 h after intradermal injection. Results indicate that although the hinge region contributes significantly to the functional specificity of the S100 protein CP-10, sustained cellular recruitment typical of a delayed type hypersensitivity response is apparently dependent on the structural integrity of the protein.

Heme active-site structural characterization of chloroperoxidase by resonance Raman spectroscopy

Resonance Raman spectra are reported for the nitric oxide adducts of ferric and ferrous chloroperoxidase and carbon monoxide adducts of ferrous chloroperoxidase. The stretching, v(Fe-NO), and bending, delta(FeNO), modes are detected at 538 and 558 cm-1, respectively, for the ferric nitrosylchloroperoxidase. These two bands shift to 534 and 546 cm-1, respectively, upon substitution by 15N16O. The v(Fe-NO) mode of the nitric oxide adduct of ferrous chloroperoxidase is located at 542 cm-1, which shifts to 528 (15N16O), 540 (14N18O), and 524 (15N18O) cm-1 as the mass of the bound nitric oxide increases by 1 atomic unit. Two distinct states of the carbon monoxide adduct of chloroperoxidase, the acidic and alkaline forms, are found to undergo a reversible pH-induced transition. The v(Fe-CO) mode shifts from 484 to 492 cm-1 and the delta(FeCO) mode at 562 cm-1 disappears as the pH is reduced from 6.0 to 3.3. In addition, two low frequency modes at 382 and 420 cm-1, assignable to the delta(CbC1C2) bending of propionate and vinyl groups, respectively, also show pH sensitivity. The results suggest a peroxidase-like heme active-site environment for chloroperoxidase and indicate a facile conformational change of heme groups accompanying the acid-base transition.

Activation of K+ channel in vascular smooth muscles by cytochrome P450 metabolites of arachidonic acid

Arachidonic acid can be oxidatively metabolized by cytochrome P450 epoxygenase to four regioisomeric epoxyeicosatrienoic acids (5,6-; 8,9-; 11,12-; 14,15-EET), which exhibit vasorelaxant effects in vivo and in vitro with unknown mechanisms. In this study, the patch-clamp method was used to examine the effects of EETs on the Ca(2+)-activated K+ channel in cells from rabbit portal vein, rat caudal artery, guinea pig aorta and porcine coronary artery. In all four cell types, EETs in the bath activated the K+ channel in cell-attached patches by increasing the single channel open-state probability. Potencies of the four EETs did not differ significantly for each cell type. The concentrations for doubling open-state probability were 0.1 microM in portal vein and coronary artery, 0.3-1 microM in aorta and 1-3 microM in caudal artery. In caudal artery cells, K+ channel activation by 3 microM 5,6- and 1 microM 11,12-EET was blocked and reversed by glyburide at 0.5 microM. In aorta, coronary artery, and caudal artery cells, micromolar EETs induced a dose-dependent and reversible augmentation of whole-cell K+ current by 50-120% and a 5-12 mV hyperpolarization. EETs on the cytosolic side of inside-out patches produced little or no potentiation of K+ channels, implying an interaction of receptor-mediated nature. Thus, EETs may promote vasodilation by functioning as endogenous K+ channel openers.

Coupling of endothelin receptors to ion channels in rat glomerular mesangial cells

Endothelin (ET) induces depolarization and contraction of glomerular mesangial cells (MCs), thereby influencing intraglomerular hemodynamics and filtration rate. In an attempt to clarify the ionic mechanism by which ET regulates MC function, we examined, using the whole-cell configuration of the patch-clamp technique, the effects of ET-1 and its related peptides, ET-3, sarafotoxin 6c (S6c), and IRL 1620, on ion currents and membrane potential in the primary culture of rat MCs. The resting potential of MCs was -48.4 +/- 1.9 mV (n = 23). It depolarized in response to ET-1, ET-3, and IRL 1620 by 14 (n = 7), 8 (n = 5), and 13 mV (n = 9), respectively. Whole-cell recording in combination with ion substitution ascertained the coexistence of potassium (IK) and chloride (ICl) currents. ET-1 (0.01-100 nM), ET-3 (1-100 nM), IRL 1620 (0.1-100 nM), and S6c (0.01-10 nM) augmented ICl in a concentration-dependent fashion, with ET-1 and S6c being the most potent. These actions were blocked by IRL 1038, a selective ETB receptor antagonist, but not by 1 microM BQ 123 (a selective ETA receptor antagonist) or 0.1 microM nifedipine (an L-type Ca(2+)-channel blocker). These results suggest a close coupling of the ETB receptor to ICl. ET-1, IRL 1620, and SRTX-6c in a similar concentration range also caused suppression of IK. This action was partially blocked by IRL 1038 and minimally affected by BQ 123, indicating a contributory role for ETB receptors in the regulation of IK.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of transforming growth factor-beta on murine astrocyte glutamine synthetase activity. Implications in neuronal injury

Cytokines have been implicated in the pathogenesis of a number of brain diseases in which neurological dysfunction has been attributed to a change in amino acid neurotransmitter metabolism. In the present in vitro study, we investigated the effects of cytokines on astrocyte glutamine synthetase (GS) activity and subsequently on N-methyl-D-aspartate (NMDA) receptor-mediated neurotoxicity. Proinflammatory cytokines IL-1 alpha, IL-1 beta, and IL-6 at a concentration of 20 ng/ml did not affect GS activity; however, tumor necrosis factor-alpha inhibited this activity by 20% in mixed neuronal/astrocyte cultures. Treatment for 24 h with transforming growth factor (TGF)-beta 1 or -beta 2 inhibited up to 60% GS activity. TGF-beta 2 also inhibited GS in enriched astrocyte cultures with an ED50 of 10 pg/ml. Antibodies specific to TGF-beta 2 blocked this effect. Treatment of astrocytes with TGF-beta 2 (250 pg/ml) resulted in markedly dilated rough endoplasmic reticulum. Since astrocyte GS may play a protective role in NMDA receptor-mediated neurotoxicity, we treated mixed neuronal/astrocyte cultures with TGF-beta 2 (250 pg/ml) and found a threefold potentiation of NMDA receptor-mediated neurotoxicity. These data suggest that TGF-beta impairs astrocyte GS function and enhances neurotoxicity, thus providing insight into understanding one mechanism of cytokine-mediated central nervous system disease.

Resonance Raman studies of the carbonmonoxy form of catalase. Evidence for and effects of phenolate ligation

Resonance Raman spectra are reported for the carbon monoxide (CO) adduct of catalase formed from the reaction of peracetic acid or hydrogen peroxide with the azide adduct of catalase in the presence of CO. The expected three normal vibrations of the FE-CO fragment are detected at 1,908,593 and 543 cm-1 for the nu(C-O), delta(Fe-C-O) and nu(Fe-CO), respectively. The expected coordination of the phenolate group in this adduct is confirmed by the enhancement of an internal vibration of phenolate, nu 19a at 1,515 cm-1, and an extraordinary intensity enhancement of the nu(Fe-CO) mode.

Positive thinking reduces heart rate and fear responses to speech-phobic imagery

30 speech-anxious subjects imagined a phobic speech scene 10 times. The experimental conditions varied according to whether the subjects engaged in positive, neutral, or negative thinking prior to each scene presentation. Heart rate and self-reports of fear were measured during the imagery periods. Positive thinking just before visualization of the phobic images reduced both subjective anxiety about speech and cardiovascular responses.

Microglial cell upregulation of HIV-1 expression in the chronically infected promonocytic cell line U1: the role of tumor necrosis factor-alpha

Culture supernatants from lipopolysaccharide (LPS)-treated murine microglial cells were found to markedly induce the expression of human immunodeficiency virus (HIV)-1 in the chronically infected human promonocytic cell line U1 as detected by measurements of HIV-1 p24 antigen release into U1 culture supernatants. Antibody to tumor necrosis factor (TNF)-alpha had an inhibitory effect on the induction of virus by microglial cell supernatants. Also, treatment of microglia with pentoxifylline, an inhibitor of TNF-alpha production, resulted in suppressed amounts of TNF in the supernatants of LPS-treated microglia and in a reduced stimulatory capacity of these supernatants on HIV-1 expression in U1 cells. These findings support the concept that TNF-alpha production by glial cells plays a pathogenetic role in HIV-1-associated brain disease by promoting the expression of the virus in infected cells.

[3H]2-phenylaminoadenosine ([3H]CV 1808) labels a novel adenosine receptor in rat brain

Earlier studies have demonstrated that the vasoactive compound CV 1808 displays 10-fold selectivity for the adenosine A2 receptor, and as such, was the first reported A2-selective agonist. After the radiolabeling of CV 1808, its binding characteristics were evaluated in rat striatal, cortical and hippocampal membranes. Using 5 nM [3H]CV 1808, unlabeled CV 1808 produced shallow inhibition curves in all three brain areas, with 61 to 75% of the binding displaying IC50 values of 16 to 24 nM, whereas the remaining 28 to 37% of binding had lower affinity (IC50 595-1130 nM). The A2-selective agonist CGS 21680 and the nonselective adenosine agonist 5'-N-ethylcarboxamidoadenosine displayed very low affinity (IC50 > 10 microM). The A1-selective compound N6-cyclopentyladenosine inhibited only 28 to 44% of specific binding, with IC50 of 272-1750 nM. In contrast, the nonselective adenosine antagonist CGS 15943A inhibited specific binding by 48 to 64% (at 1 microM) with IC50 ranging from 106 to 295 nM. Additionally, several novel adenosine analogs fully inhibited specific binding, producing multicomponent inhibition curves. Electrophysiological studies in porcine coronary artery cells demonstrated that CV 1808, but not CGS 21680, 5'-N-ethylcarboxamidoadenosine and N6-cyclopentyladenosine, activated potassium channels. Further, the CV 1808-induced activation was blocked by CGS 15943A. These results indicate that [3H]CV 1808 binding consists of two components in rat brain: a low-affinity site with A1-like characteristics, and a novel high-affinity site, designated as the A4 receptor, where potassium channel activation appears to be a functional correlate.

Activated microglia mediate neuronal cell injury via a nitric oxide mechanism

Activated microglial have been proposed to play a pathogenetic role in immune-mediated neurodegenerative diseases. To test this hypothesis, purified murine neonatal microglial were cocultured with neuronal cells derived from fetal brain. Activation with IFN-gamma and LPS of these cocultures brought about a sharp decrease in uptake of gamma-amino butyric acid and a marked reduction in neuronal cell survival. These effects varied with the density of microglia, the concentrations of the activation signals (IFN-gamma and LPS), and the duration of coculture. Inasmuch as addition of NG-monomethyl-L-arginine blocked these effects, a L-arginine-dependent neurocytotoxic mechanism was implicated. Abundant nitrite, a metabolite of the free radical nitric oxide (NO) derived from L-arginine, was detected in activated microglial/neuronal cell cocultures and in purified microglial cell cultures but not in purified astrocyte or neuronal cell cultures, suggesting that microglial were the principal source of the NO. These findings support the hypothesis that microglia are the source of a neurocytotoxic-free radical, and shed light on an additional mechanism of immune-mediated brain injury.

Activated microglia mediate neuronal cell injury via a nitric oxide mechanism

Activated microglial have been proposed to play a pathogenetic role in immune-mediated neurodegenerative diseases. To test this hypothesis, purified murine neonatal microglial were cocultured with neuronal cells derived from fetal brain. Activation with IFN-gamma and LPS of these cocultures brought about a sharp decrease in uptake of gamma-amino butyric acid and a marked reduction in neuronal cell survival. These effects varied with the density of microglia, the concentrations of the activation signals (IFN-gamma and LPS), and the duration of coculture. Inasmuch as addition of NG-monomethyl-L-arginine blocked these effects, a L-arginine-dependent neurocytotoxic mechanism was implicated. Abundant nitrite, a metabolite of the free radical nitric oxide (NO) derived from L-arginine, was detected in activated microglial/neuronal cell cocultures and in purified microglial cell cultures but not in purified astrocyte or neuronal cell cultures, suggesting that microglial were the principal source of the NO. These findings support the hypothesis that microglia are the source of a neurocytotoxic-free radical, and shed light on an additional mechanism of immune-mediated brain injury.

Cytokine release from microglia: differential inhibition by pentoxifylline and dexamethasone

Cytokines have been implicated in the pathogenesis of gram-negative bacterial meningitis. The effects of pentoxifylline and dexamethasone on the release of tumor necrosis factor (TNF), interleukin (IL)-1, and IL-6 from primary murine microglial cell cultures were explored using bioassays. When added concomitantly with lipopolysaccharide, pentoxifylline blocked the release of TNF and IL-1 but not IL-6, while dexamethasone inhibited the release of TNF and IL-6. After a 2-h exposure of microglia to lipopolysaccharide, pentoxifylline but not dexamethasone still inhibited the release of TNF. Release of TNF was enhanced 20-fold by priming of the microglia with interferon-gamma; only pentoxifylline blocked the priming effect of interferon-gamma on TNF release. These results demonstrate that pentoxifylline and dexamethasone differentially regulate the release of cytokines in microglial cell cultures and provide potential insight into their role in the treatment of gram-negative bacterial meningitis.

Influence of medicinal herbs on phagocytosis by bovine neutrophils

Twenty-six herbal preparations made from 24 medicinal herbs, categorized as antipyretics in Chinese materia medica, were tested in vitro to determine their effects upon phagocytosis of 32P-labelled Staphylococcus aureus by neutrophils isolated from bovine blood and milk. The percentage of phagocytosis was determined after incubating (1 hour at 37 degrees C) 1.25 x 10(7) neutrophils, 1 x 10(8) 32P-labelled S. aureus and 10% skimmed milk with herbal solutions. Concentrations of herbal preparations tested were 100%, 10% and 1% (v/v). When compared with PBSS (0.01 M phosphate buffered saline solution) controls, most of the herbs at high concentrations inhibited phagocytosis while at lower concentrations phagocytosis was increased. All 26 herbal preparations significantly increased blood neutrophil activity at their proper concentrations. The most active herbs in promoting blood neutrophil phagocytosis were observed for Herba verbenae, Flos chrysanthemi, Flos lonicerae, Radix sophorae flavescentis, Herba houttuyniae, Radix isatidis, Herba patriniae, Berberini sulfatis at the lowest concentration and for Folium hibisci at the high concentration with the increased percentage of more than 40.0% in comparison with PBSS control. Of the 19 herbal preparations tested with milk neutrophils, 18 herbs greatly increased phagocytosis at suitable concentrations. The most active preparations in stimulating milk neutrophil functions included Folium hibisci, Flos chrysanthemi, Radix bupleuri, Radix stellariae, Herba houttuyniae, Herba senecionis scandentis, Caulis lonicerae and Flos lonicerae which increased phagocytosis by over 35.0%.

[Establishment and preliminary application of competitive ELISA using monoclonal antibody against Trichinella spiralis]

Monoclonal antibody competitive ELISA was devised with a highly specific McAb (2G8) against T. spiralis. Among 20 rabbits infected with T. spiralis experimentally. 35% (7/20) were positive on the 17th day post infection (PI); 100% positive on the 31st day PI. No cross reaction was found with 29 sera of rabbits infected with other kinds of helminth. The dynamic antibody titer of five infected rabbits sera were studied with this method. The change may be helpful to judge the state of infection. In short, anti-T. spiralis McAb competitive ELISA can be regarded as a sensitive and specific immunological diagnostic method for T. spiralis infection.

Support of human hematopoiesis in long-term bone marrow cultures by murine stromal cells selectively expressing the membrane-bound and secreted forms of the human homolog of the steel gene product, stem cell factor

The maintenance and differentiation of hematopoietic stem cells is influenced by cells making up the hematopoietic microenvironment (HM), including bone marrow-derived stromal cells. We and several other investigators have recently demonstrated the molecular basis of abnormal HM observed in the steel mutant mouse and cloned the normal cDNA products of this gene (termed SCF, KL, or MCF). In this report, we focus on the human counterpart of the mouse Steel (Sl) gene. Alternative splicing of the human SCF pre-mRNA transcript results in secreted and membrane-bound forms of the protein. To investigate the role of these two forms of human SCF, we targeted an immortalized stromal cell line derived from fetal murine homozygous (Sl/Sl) SCF-deficient embryos for gene transfer of various human cDNAs encoding SCF. We report that stable stromal cell transfectants can differentially process the two forms of human SCF protein product. We also demonstrate that both soluble SCF and membrane-bound SCF are active in increasing the number of human progenitor cells in the context of stromal cell cultures, although in a qualitatively different manner. Hence, the membrane-bound form of SCF may play an important role in the cell-cell interactions observed between stromal and hematopoietic cells both in vitro and in vivo.

Immunologically mediated fatigue: a murine model

Chronic fatigue syndrome (CFS) is an idiopathic disorder in which the chief symptoms is profound fatigue. To explore the relationship between immune stimulation and fatigue, we developed a murine model for quantifying fatigue: reduction in voluntary running and delayed initiation of grooming after swimming. Inoculation of female BALB/c mice with Corynebacterium parvum antigen or the relatively avirulent Me49 strain of Toxoplasma gondii induced fatigue: baseline running reduced to less than 50 and 30% for 8 and 14 days, respectively, and delayed initiation of grooming after swimming in both immunologically stimulated groups. A threefold evaluation of serum transforming growth factor-beta levels, a cytokine increased in CFS patients, was found in fatigued C. parvum- and T. gondii-inoculated mice. This murine model appears promising for investigation of the pathogenesis of immunologically mediated fatigue.

[The use of 6-flavor Rehmannia decoction with additives in the prevention of ototoxic deafness induced by gentamicin in guinea pigs]

The purpose of this study is to discuss the effects of the Chinese medicine six-flavor Rehmannia Decoction with additives on preventing deafness induced by gentamicin (GM) in guinea pig by means of testing the thresholds of Preyer's reflex (PR) cochlear microphonic potential (CM), action potential of the auditory nerve (N1) and scanning electron microscope of inner ear (SEM). The results showed that the medicine is effective in reducing the ototoxic effect of GM on inner ear.

Characterization of the copper- and silver-thiolate clusters in N-terminal fragments of the yeast ACE1 transcription factor capable of binding to its specific DNA recognition sequence

N-terminal fragments of ACE1 protein spanning residues 1-122 or 1-110, termed ACE1(122*) and ACE1(110*), respectively, were investigated in regard to their metal- and double-stranded DNA-binding properties. Band mobility shift assays showed that binding to a specific oligonucleotide (termed UASc), containing two ACE1(122*) binding sites, requires the presence of Cu(I) or Ag(I) but does not occur in the presence of divalent metal ions. Both the Ag(I) and the Cu(I) forms of ACE1(122*) were characterized spectroscopically. The Tyr and metal cluster luminescence emission of Cu-ACE1(122*) was specifically quenched by the oligonucleotide UAScL, but not by an oligonucleotide of the same length and base composition but scrambled sequence. The room-temperature luminescence of Cu(I)-ACE1(122*) was assigned to a phosphorescence emission, on the basis of its long-lived luminescence of approximately 3.5 microseconds. We report the first observation of a Ag(I) metal cluster in solution for Ag(I)-ACE1(122*), which was found to exhibit a quantum yield and average luminescence lifetime that are ca. 6% of that of Cu(I)-ACE1(122*). The three-dimensional structure brought about by the binding of either metal ion appears to be very similar, since dynamic tyrosine fluorescence lifetime measurements, as well as circular dichroism spectra, were nearly identical for Cu- and Ag-ACE1(122*). Based on these results, we present a hypothetical model for the structure of the metal cluster in this class of proteins.

Morphine potentiates transforming growth factor-beta release from human peripheral blood mononuclear cell cultures

Opiates modulate a variety of immune responses by peripheral blood mononuclear cells (PBMC). In the present study, we investigated the effect of morphine on the release of several cytokines upon stimulation with mitogens. An interleukin (IL)-4-dependent HT-2 cell proliferation assay was used to quantify transforming growth factor-beta (TGF-beta). IL-6 and tumor necrosis factor-alpha (TNF-alpha) were measured by enzyme-linked immunosorbent assays. Morphine (1 pM and 10 nM) alone did not significantly modulate the release of TGF-beta, IL-6 or TNF-alpha. Upon stimulation with lipopolysaccharide and phytohemagglutinin, PBMC released more (P less than .01) TGF-beta, IL-6 and TNF-alpha than unstimulated PBMC. Exposure of PBMC to morphine (1 pM) for 24 hr substantially amplified (P less than .05) the release of TGF-beta in the following 24 hr incubation period. Morphine did not alter the release of immunodetectable IL-6 or TNF-alpha from stimulated cells. The amplifying effect of morphine on the release of TGF-beta was mediated through a naloxone-sensitive mechanism. Given the fact that TGF-beta has a potent immunosuppressive effect, morphine-potentiated release of TGF-beta from PBMC may be involved in the immunomodulatory activity ascribed to morphine.

Neu differentiation factor: a transmembrane glycoprotein containing an EGF domain and an immunoglobulin homology unit

We recently reported that a 44 kd glycoprotein secreted by transformed fibroblasts stimulates tyrosine phosphorylation of the product of the neu proto-oncogene and induces differentiation of mammary tumor cells to milk-producing, growth-arrested cells. A partial amino acid sequence of the protein, termed Neu differentiation factor (NDF), enabled cloning of the corresponding complementary DNA. The deduced structure of the precursor of NDF indicated that it is a transmembrane protein whose extracellular portion contains an EGF-like domain that probably functions as a receptor recognition site. In addition, the ectodomain contains one immunoglobulin homology unit. Despite the lack of a recognizable hydrophobic signal peptide at the N-terminus, a recombinant NDF, like the natural molecule, is released into the medium of transfected COS-7 cells in a biologically active form. Northern blot analysis indicated the existence of several NDF transcripts, the major ones being 1.8, 2.6, and 6.7 kb in size. Transformation by the ras oncogene dramatically elevated the expression of NDF in fibroblasts.

Neuroprotective effects of graded reoxygenation following chronic hypoxia in neuronal cell cultures

The present study was undertaken to investigate the comparative effects of rapid vs graded correction of chronic hypoxia in vitro. Cerebral cortical cell cultures obtained from fetal mice were exposed to 5% O2 for 24 h and returned immediately to room air for the following 24 h (Group I); comparable cultures were exposed to 5% O2 for 24 h followed by 10% O2 for an additional 24 h before return to room air (Group II). At the conclusion of the experimental protocol (time 0), partial pressure of oxygen in the bathing medium of Group I cultures was significantly higher than that of Group II and non-hypoxic controls (151 mmHg vs 124 and 132 mmHg, respectively; P less than 0.05). Throughout the recovery period, Group II cultures evidenced improved neuronal survival (e.g. 35,800 vs 17,700 neurons/culture well at time 0, P less than 0.01), decreased lactate dehydrogenase efflux into the bathing medium, relative preservation of neuronal morphology, as well as higher specific and clonazepam-displaceable benzodiazepine binding and GABA uptake. Glutamate binding was not differentially affected and glutamine synthetase activity, a predominantly glial marker, was only modestly increased after graded reoxygenation. These results demonstrate that gradual reoxygenation after prolonged hypoxia in vitro (i) improves neuronal survival compared to rapid reoxygenation and (ii) delays the manifestations of metabolic dysfunction even though the length of hypoxic exposure is increased. The findings are also consistent with the concept that a period of relative hyperoxia may contribute to hypoxia-induced neuronal injury.

Electrical acustimulation relieves vection-induced motion sickness

The aim of this study was to examine the effects of electrical acustimulation on gastric myoelectric activity and severity of symptoms of motion sickness. In experiment 1, 16 Chinese subjects received electrical acustimulation in one of two sessions. In experiment 2, 45 white and black American subjects were randomly divided into three groups: acustimulation, sham acustimulation, and control. Each subject sat in an optokinetic drum for 15 minutes baseline and 15 minutes of drum rotation. Subjects' electrogastrograms and subjective symptoms of motion sickness were obtained. In experiment 1, the mean symptom score and tachyarrhythmia during acustimulation sessions were significantly lower than during no-acustimulation sessions. In experiment 2, the mean symptom score of the acustimulation group was significantly lower than that of the sham-stimulation group and the control group; tachyarrhythmia in the acustimulation group was significantly less than that of the control group but not the sham-stimulation group. In conclusion, electrical acustimulation reduces the severity of symptoms of motion sickness and appears to decrease gastric tachyarrhythmia.

A randomized comparative trial of the MLCu375, TCu220C, steel ring and uterine cavity-shaped IUDs

The Stainless Steel Ring, Uterine Cavity-Shaped Device, TCu220C and MLCu375 IUDs were evaluated in a randomized trial of 1536 women in Guangdong Province, China. The first-year continuation and expulsion rates were significantly lower (p less than 0.05) for the latter 3 IUDs than for the Stainless Steel Ring. The first year pregnancy rates for the MLCu375 (0.76 per 100 women) and TCu220C (1.2 per 100 women) were significantly lower (p less than 0.05) than those of the other two devices (6.1 and 4.1 per 100 women). The results of the study show that the MLCu375 and TCu220C are the most suitable IUDs for women in Guangdong Province.

[An animal model of posttraumatic multiple system organ failure (MSOF)]

Hemorrhagic shock, sepsis, excessive systemic inflammatory reactions, and failure of intestinal mucosal barrier function are known to be major predisposing factors in the development of MSOF in patients after severe trauma or burns. We investigated the possibility of complicating clinically simulating MSOF in animals. Our results showed that, with compounded traumatic factors, including damages to the bowel, and proper circulatory and respiratory support, an animal model which simulated the pathophysiology and histopathology of MSOF could be reproduced to offer opportunity for the study of mechanisms and therapy. Markers of MSOF were also described for reference.

Drosophila single-minded gene and the molecular genetics of CNS midline development

Our goal is to understand the molecular mechanisms that govern the formation of the central nervous system. In particular, we have focused on the development of a small group of neurons and glia that lie along the midline of the Drosophila CNS. These midline cells possess a number of unique attributes which make them particularly amenable to molecular, cellular, and genetic examinations of nervous system formation and function. In addition, the midline cells exhibit distinctive ontogeny, morphology, anatomical position, and patterns of gene expression which suggest that they may provide unique functions to the developing CNS. The single-minded gene encodes a nuclear protein which is specifically expressed in the midline cells and has been shown to play a crucial role in midline cell development and CNS formation. Genetic experiments reveal that sim is required for the expression of many CNS midline genes which are thought to be involved in the proper differentiation of these cells. In order to identify additional genes which are expressed in some or all of the midline cells at different developmental stages, a technique known as enhancer trap screening was employed. This screen led to the identification of a large number of potential genes which exhibit various midline expression patterns and may be involved in discrete aspects of midline cell development. Further molecular, genetic, and biochemical analyses of sim and several of the enhancer trap lines are being pursued. This should permit elucidation of the genetic hierarchy which acts in the specification, differentiation, and function of these CNS midline cells.

Glioblastoma, transforming growth factor-beta, and Candida meningitis: a potential link

The development of Candida meningitis in a patient following partial resection of a glioblastoma raised suspicion that transforming growth factor (TGF-beta), an immunosuppressive cytokine known to be produced by this tumor, would be elevated in his cerebrospinal fluid (CSF). By using a highly specific bioassay, the concentration of TGF-beta was found to be 609 pg/mL, which was 10-fold greater than the mean CSF TGF-beta value in control subjects with no neurologic disease. Increased CSF TGF-beta levels were also detected in patients with other central nervous system (CNS) diseases: malignancies and AIDS dementia complex. These findings suggest that TGF-beta may play an immunopathogenetic role in the CNS.

Determination of trace amounts of estriol and estradiol by adsorptive cathodic stripping voltammetry

Estriol and estradiol are electroinactive in the potential range from -200 to -1000 mV versus a silver-silver chloride electrode at a mercury electrode. The conversion of these estrogens into electroactive nitro derivatives of estrogens, which are used for voltammetric determination, was studied. Such nitro derivatives give a well defined cathodic stripping wave at -600 mV in pH 10.5 borate buffer. Estriol and estradiol are determined in the ranges 1 x 10(-9)-1.5 x 10(-6) and 5 x 10(-9)-2 x 10(-6) mol dm-3, respectively, by differential-pulse adsorptive stripping voltammetry at a hanging mercury drop electrode. Some steroids, such as estrone, interfere because the three estrogens have almost the same molecular structure and have similar nitro derivatives, but progesterone does not interfere and is reduced at significantly more negative potentials than the nitrated estrogens. It can be determined simultaneously with estriol or estradiol. A method was developed for the assay of estriol in pharmaceutical preparations.

Varus rotational femoral osteotomies in adults with hip dysplasia

Fifty-six hips in 48 consecutive patients operated on for congenital dysplasia of the hip during the years 1971 through 1986 were evaluated for an average follow-up period of nine years (range, two-21 years). Twenty-three percent of the patients were treated with revision to total hip arthroplasty by the time of follow-up examination. The average time before revision was 8.6 years. All but three of the remaining hips were rated good or excellent (72%). These patients tended to have minimal or no preoperative degenerative joint disease. Complications included one subtrochanteric fracture, two cases of loss of fixation, and one superficial wound infection. The authors conclude that the operation provides predictable, high-quality results in those patients with minimal or no degenerative changes preoperatively. In those patients with mild or moderate degenerative changes, it may forestall the onset of severe symptoms by several years.