Serum cytokine levels in patients with Alzheimer's disease

Alzheimer's disease (AD) has been proposed to be an inflammatory disorder. In a recent study, markedly elevated levels of the anti-inflammatory cytokine transforming growth factor beta (TGF-beta) in the serum and cerebrospinal fluid of patients with advanced AD suggested a potential predictive value of this cytokine in patients with AD. In the present prospective study, we tested the hypothesis that the levels of TGF-beta in serum would be increased in patients with AD and could thereby serve as a diagnostic marker. We found that serum TGF-beta levels but not proinflammatory cytokine levels were significantly (P < 0.05) elevated in patients with AD (n = 22) in comparison with the levels in their healthy spousal controls. Also, serum TGF-beta levels were positively correlated (r = 0.45; P < 0.05) with disease severity. Nevertheless, the elevation in serum TGF-beta levels in patients with Ad was modest, and considerable overlap with the control values suggests that the diagnostic usefulness of this cytokine for AD is limited.

Cytomegalovirus replication in murine microglial cell cultures: suppression of permissive infection by interferon-gamma

The pathogenesis of encephalitis due to cytomegalovirus (CMV), particularly the role of microglial cells in the spread or control of infection, remains incompletely defined. In this study, microglial cells were isolated from the brains of newborn mice and infected in vitro with murine CMV (MCMV). Microglial cells supported productive MCMV replication, and the MCMV-infected microglia manifested a cytopathic effect (CPE) characteristic of CMV infection. Exposure of microglia to interferon-gamma (IFN-gamma) 24 h before infection markedly suppressed virus production and resultant CPE in a dose-dependent fashion. Furthermore, the addition of IFN-gamma 2 h after infection demonstrated an antiviral effect equivalent to that achieved when IFN-gamma was administered 2 h before infection. These results demonstrate that murine microglial cells are fully permissive to MCMV replication and that IFN-gamma markedly suppresses virus expression in these cells.

Priming effect of morphine on the production of tumor necrosis factor-alpha by microglia: implications in respiratory burst activity and human immunodeficiency virus-1 expression

Opiates alter a variety of functional activities of the somatic immune system; within the central nervous system, however, their effects on immune responses are unknown. In the present study, we investigated the effect of morphine on the release of tumor necrosis factor (TNF)-alpha from murine neonatal microglia. Microglial cell cultures did not release TNF-alpha when incubated with morphine alone; however, an enhanced (P < .01) release of TNF-alpha was observed when cultures were first primed with morphine for 24 h and then stimulated with lipopolysaccharide. A bell-shaped dose-response curve was observed for the priming effect of morphine; maximal enhancement of TNF-alpha release (310 +/- 15% of control) was detected at a concentration of 10(-10) M morphine. Pretreatment of microglia for 30 min with opioid receptor antagonists (i.e. naloxone and beta-funaltrexamine) completely blocked the priming effect of morphine. In addition, morphine treatment amplified (P < .01) the priming effect of lipopolysaccharide on phorbol myristate acetate-triggered superoxide anion production by microglial cell cultures, and this effect was abrogated (P < .01) by anti-TNF-alpha antibody. Furthermore, culture supernatants derived from microglial cell cultures that had been treated with morphine before stimulation with lipopolysaccharide had an increased capacity to upregulate human immunodeficiency virus-1 expression in the latently infected promonocytic clone U1. This effect was also blocked by anti-TNF-alpha antibody. These findings suggest that morphine primes microglia for enhanced production of TNF-alpha which could alter several functional activities of these cells within the brain.

The raspberry locus of Drosophila melanogaster includes an inosine monophosphate dehydrogenase like coding sequence

DNA from the raspberry gene of Drosophila melanogaster has been cloned through P-element tagging of a dysgenically induced lethal allele. A transcribed DNA segment adjacent to the P insert encodes an amino acid sequence that is similar to known inosine monophosphate dehydrogenase (IMPDH) sequences. Further dysgenically induced lethals and all four known spontaneous ras eye-colour mutations have changes in the DNA either within or just upstream from the transcribed region. Identification of IMPDH as a probable product of the ras gene is compatible with the finding of an allele that requires dietary guanosine (GR), since the enzyme mediates the first of two biosynthetic steps leading from inosine monophosphate (IMP) to guanosine monophosphate (GMP). However, other auxotrophic mutants at the locus remain unexplained by the finding. The results further suggest that GMP synthesis from IMP is an essential process, despite the capacity of the fly for salvage synthesis of GMP from GR. Consideration of the phenotypes associated with mutants at the ras locus suggests that IMPDH activity is regulated in a tissue-specific manner.

Effects of mild exercise on cytokines and cerebral blood flow in chronic fatigue syndrome patients

Chronic fatigue syndrome (CFS) is an idiopathic disorder characterized by fatigue that is markedly exacerbated by physical exertion. In the present study, we tested the hypothesis that mild exercise (walking 1 mph [1 mile = 1.609 km] for 30 min) would provoke serum cytokine and cerebral blood flow abnormalities of potential pathogenic importance in CFS. Interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha were nondetectable in sera of CFS patients (n = 10) and healthy control subjects (n = 10) pre- and postexercise. At rest, serum transforming growth factor beta (TGF-beta) levels were elevated in the CFS group compared with the control group (287 +/- 18 versus 115 +/- 5 pg/ml, respectively; P < 0.01). Serum TGF-beta and cerebral blood flow abnormalities, detected by single-photon emission-computed tomographic scanning, were accentuated postexercise in the CFS group. Although these findings were not significantly different from those in the control group, the effect of exercise on serum TGF-beta and cerebral blood flow appeared magnified in the CFS patients. Results of this study encourage future research on the interaction of physical exertion, serum cytokines, and cerebral blood flow in CFS that will adopt a more rigorous exercise program than the one used in this study.

Role of cytokines in lipopolysaccharide-induced functional and structural abnormalities of astrocytes

The mechanism underlying meningitis-associated brain injury is unclear. This study investigated the hypothesis that lipopolysaccharide (LPS) alters astrocyte function and structure via the release of proinflammatory cytokines. In enriched murine astrocyte cultures, LPS inhibited (P < 0.05) glutamine synthetase activity, 3H-gamma aminobutyric acid uptake, and DNA synthesis; LPS also induced ultrastructural changes. Antibodies to tumor necrosis factor-alpha, interleukin-1, and interleukin-6 blocked (P < 0.05) in part the LPS-induced inhibition of astrocyte function. Also, treatment of astrocyte cultures with cytokines significantly altered these astrocyte functions and ultrastructure. Taken together, the present findings support the hypothesis that LPS affects astrocyte function and structure via the release of proinflammatory cytokines, especially tumor necrosis factor-alpha.

Morphine amplifies HIV-1 expression in chronically infected promonocytes cocultured with human brain cells

Previous studies have shown that morphine promotes the replication of human immunodeficiency virus (HIV)-1 in peripheral blood mononuclear cell cocultures. In the present study, we tested the hypothesis that morphine would amplify HIV-1 expression in the chronically infected promonocytic clone U1 when cocultured with lipopolysaccharide-stimulated human fetal brain cells. Marked upregulation of HIV-1 expression was observed in these cocultures (quantified by measurement of HIV-1 p24 antigen levels in supernatants), and treatment of brain cells with morphine resulted in a bell-shaped dose-dependent enhancement of viral expression. The mechanism of morphine's amplifying effect appears to be opioid receptor-mediated and to involve enhanced production of tumor necrosis factor-alpha by microglial cells.

Human microglial cell defense against Toxoplasma gondii. The role of cytokines

Microglia may play an important role in host defense of the central nervous system against Toxoplasma gondii, and cytokines produced by these glial cells may participate in their antitoxoplasma activity. In our study, the antitoxoplasma activity of human fetal microglia was investigated. The RH strain of T. gondii multiplied readily in these glial cells. IFN-gamma/LPS-treated microglia limited (p < 0.01) T. gondii growth by reducing entry of this parasite rather than intracellular multiplication. More than 90% of the antitoxoplasma activity of activated microglia was blocked (p < 0.01) by neutralizing antibodies to TNF-alpha or IL-6 (but not to IL-1 or TGF-beta), suggesting that these proinflammatory cytokines play a role in the inhibitory process. Consistent with this hypothesis, treatment of microglia with TNF-alpha or IL-6 (in the presence or absence of IFN-gamma) inhibited (p < 0.01), in a dose-dependent manner, T. gondii growth. Inasmuch as NGMA did not affect cytokine-mediated antitoxoplasma activity of microglia, nitric oxide appears not to be involved in this host defense function of human fetal microglia. Results of our study suggest that the host defense activity of human microglia against T. gondii is dependent primarily on the activating properties of IFN-gamma, TNF-alpha, and IL-6.

Human microglial cell defense against Toxoplasma gondii. The role of cytokines

Microglia may play an important role in host defense of the central nervous system against Toxoplasma gondii, and cytokines produced by these glial cells may participate in their antitoxoplasma activity. In our study, the antitoxoplasma activity of human fetal microglia was investigated. The RH strain of T. gondii multiplied readily in these glial cells. IFN-gamma/LPS-treated microglia limited (p &lt; 0.01) T. gondii growth by reducing entry of this parasite rather than intracellular multiplication. More than 90% of the antitoxoplasma activity of activated microglia was blocked (p &lt; 0.01) by neutralizing antibodies to TNF-alpha or IL-6 (but not to IL-1 or TGF-beta), suggesting that these proinflammatory cytokines play a role in the inhibitory process. Consistent with this hypothesis, treatment of microglia with TNF-alpha or IL-6 (in the presence or absence of IFN-gamma) inhibited (p &lt; 0.01), in a dose-dependent manner, T. gondii growth. Inasmuch as NGMA did not affect cytokine-mediated antitoxoplasma activity of microglia, nitric oxide appears not to be involved in this host defense function of human fetal microglia. Results of our study suggest that the host defense activity of human microglia against T. gondii is dependent primarily on the activating properties of IFN-gamma, TNF-alpha, and IL-6.

Recombinant and cellular expression of the murine chemotactic protein, CP-10

The S100 protein CP-10 (chemotactic protein, 10 kD), a potent chemotactic factor for murine and human polymorphonuclear cells (PMN) and murine monocytes, has been purified in small amounts from supernatants of activated murine spleen cells (Lackmann et al., 1992). To obtain a more abundant source of the protein, CP-10 was expressed in Escherichia coli as a fusion protein with glutathione S-transferase (GST). The property of S100 proteins to undergo calcium-dependent conformational changes was used in a novel approach to optimize the release of recombinant (r) CP-10 by thrombin cleavage. Purified rCP-10 was characterized by amino-terminal sequence analysis and bioassays. Optimal chemotactic activity of rCP-10 for murine PMN and WEHI-265 monocytoid cells was 10(-11) M (native protein has optimal chemotactic activity between 10(-11) and 10(-13) M). Immunization of rabbits with the GST/CP-10 fusion protein bound to glutathione-agarose beads resulted in high titer, specific antibodies that neutralized CP-10-initiated chemotaxis and were suitable for immunoblotting. A combination of Western and Northern analyses identified CP-10 in murine peritoneal exudate PMN and macrophages, splenocytes, bone marrow cells, and WEHI-265 cells (all of myeloid origin), but not in thymus, liver, lung, 3T3 fibroblasts, EL4 lymphoma cells, or bEND 3 brain endothelial cells, indicating cell-specific regulation of CP-10 expression.

Unbleachable rhodopsin with an 11-cis-locked eight-membered ring retinal: the visual transduction process

Visual transduction occurs through photorhodopsin, the primary photoproduct of rhodopsin, which relaxes to bathorhodopsin and a series of other intermediates until it reaches the metarhodopsin II stage, upon which the enzymatic cascade leading to vision is activated. Despite advances in areas related to visual transduction, the triggering process itself, a key problem in the chemistry of rhodopsin, has remained unsolved. In order to clarify the extent of involvement of the chromophoric excited state versus the 11-cis to trans isomerization, and as an extension of past studies with 11-cis-locked seven-membered ring rhodopsin (Rh7), 11-cis eight- and nine-membered ring retinal analogs, ret8 and ret9, respectively, have been synthesized. The bulkiness of the tetramethylene bridge in ret8 led to numerous unexpected obstacles in attempts to reconstitute a ret8-containing rhodopsin (Rh8) embedded in lipid bilayer membranes. These obstacles were solved by using methylated rhodopsin which gave MeRh8 containing 11-cis-ret8 as its chromophore. MeRh8 exhibited UV-vis and CD spectra very similar to those of native rhodopsin (Rh); furthermore, the quantum efficiency of photorhodopsin formation was comparable to that of Rh.(ABSTRACT TRUNCATED AT 250 WORDS)

Transforming growth factor beta in Alzheimer's disease

Alzheimer's disease (AD) has been hypothesized to be an inflammatory condition. We hypothesized that anti-inflammatory cytokines, such as transforming growth factor beta (TGF-beta), counteract the inflammatory process. In the present study, we found that TGF-beta levels were elevated in both cerebrospinal fluid and serum samples obtained from AD patients < 6 h after death. Serum TGF-beta levels were also markedly elevated before death. These results suggest that elevated TGF-beta levels in AD may represent a protective host response to immunologically mediated neuronal injury.

Tumor necrosis factor-alpha potentiates glutamate neurotoxicity in human fetal brain cell cultures

Cytokines may play a pathogenetic role in the brain. Using human fetal brain cell cultures, we investigated whether cytokines released during inflammation modulate neuronal injury. Exposure of human fetal neuronal cells to the excitatory amino acid neurotransmitter, glutamate, for 6 days resulted in a dose-dependent cell loss. Tumor necrosis factor (TNF)-alpha potentiated glutamate neurotoxicity. This TNF alpha-potentiated glutamate neurotoxicity was blocked by the glutamate receptor antagonists, 2-APV and MK-801, suggesting that the potentiating effect of TNF alpha is predominantly mediated by a glutamate receptor mechanism. Exposure of neuronal cultures to TNF alpha for 5 days resulted in a 27% decrease in astrocyte glutamine synthetase and in a 50% inhibition of 3H-glutamate uptake, suggesting that the effect of TNF alpha indirectly involves glutamate metabolism. These findings suggest that under pathologic conditions, TNF alpha may impair embryonic development of the brain by exacerbating excitotoxicity.

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.