Polymorphisms in the methylenetetrahydrofolate reductase and methionine synthase reductase genes and homocysteine levels in Brazilian children

Hyperhomocysteinemia is a risk factor for thrombosis, and methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) polymorphisms, folate, and B12 levels could contribute to plasma homocysteine (Hcy) variation. Although well established in adults, few studies have been performed in childhood. In this study, we investigated association of polymorphisms C677T and A1298C in the MTHFR gene and A66G in the MTRR gene with Hcy levels in children. These polymorphisms, as well as Hcy, folate, and vitamin B12 levels were investigated in 220 normal children with ages ranging from 1 to 8 years. Plasma Hcy, folate, and vitamin B12 levels were normal in all children. None of the polymorphisms could be considered an independent risk factor for hyperhomocysteinemia during childhood. The median Hcy levels in 37 children (17%) doubly heterozygous for C677T and A1298C mutations in the MTHFR gene were not different from the other genotypes. However, the association of the different genotypes with Hcy, folate, and vitamin B12 levels demonstrated significant P-values. The folate levels demonstrated a statistically significant decrease (P = 0.0477) from the C677T mutation in the MTHFR gene (TT genotype) when compared to the other groups. Folate was the only independent risk factor for hyperhomocysteinemia. Thus, monitoring the concentrations of folate would be more helpful for evaluating hyperhomocysteinemia and for preventing cardiovascular disease.     

Differentiation of the U-937 promonocytic cell line induced by phorbol myristate acetate or retinoic acid: Effect of aurothiomalate

Tissue macrophages, which participate in chronic synovial inflammation, differentiate from haemopoietic precursors in bone marrow and subsequently in tissue. During this process, they acquire attributes which are essential for their function in inflammation. Modulation of this process may represent a means of regulating inflammatory competence of macrophages in inflammatory joint disease. The action of aurothiomalate (ATM), an anti-rheumatic gold compound, on the differentiation of a promonocytic cell line (U937) was, therefore, examined inin vitro systems. U937 cells exposed to retinoic acid (RA) for 4 days or to phorbol myristate acetate (PMA) for 2 days acquired characteristics of macrophages, including the capacity to produce superoxide (O ₂ ^– ), responsiveness to formyl-methionyl-leucyl-phenylalanine (fMLP) and reduced proliferation. The activity of transglutaminase also increased in RA-exposed cultures. The effect of ATM exposure on acquisition of these characteristics was small and differed between RA- and PMA-stimulated cells.     

Antigens targeted to the Leishmania phagolysosome are processed for CD4+ T cell recognition

Processing of antigen for recognition by class II-restricted CD4⁺ T cells occurs within acidic compartments of the antigen-presenting cell. The exact nature of this compartment has yet to be precisely defined, however, but may vary depending upon the cell type studied and the antigen used. The acidic compartments of macrophages are also responsible for the degradation of ingested micro-organisms and play host to others which are adapted to an intracellular existance. To determine whether the phagolysosome (PL) formed in activated macrophages after ingestion of Leishmania parasites is also a site for entry of antigen into the class II presentation pathway, we have used the approach of genetic transformation. Hence, Leishmania were transfected with the genes for the protein antigens ovalbumin (OVA) and β-galactosidase (β-gal) and after infection were able to deliver these antigens specifically into the PL. Delivery of antigen to this site resulted in the ability of infected macrophages to present these antigens to antigen-specific CD4⁺ T cells. After taking into account the absolute levels of antigen uptake by macrophages, a 4-h processing period for OVA delivered by this or a soluble route led to equivalent levels of T cell activation. Unlike macrophages pulsed with soluble OVA, those with PL-targeted OVA still retained the ability to stimulate T cells after a 24-h processing period. This enhanced lifespan of antigen in macrophages corresponded to the kinetics of degradation of the parasite, suggesting slow release of antigen into the processing pathway. β-gal presentation from the PL was tenfold less efficient under the same conditions. In addition to providing the first information on antigen processing in a protozoan PL, these studies highlight the usefulness of genetically transformed parasites for these types of studies.     

The influence of age,sex and race on salivary kallikrein levels in human mixed saliva

Variation in the level of salivary kallikrein in human saliva has been reported as a function of systemic conditions such as reduced salt intake and during the menstrual cycle. Higher levels of salivary kallikrein have been observed in subjects with tumors distant from the oral cavity when compared to control subjects. These studies have not evaluated factors, such as age, which might influence the concentration of glandular kallikrein in saliva. The purpose of the preseut study was to determine the variation of salivary kallikrein concentration as a function of age. Differences attributable to sex or race were also evaluated. Mixed saliva was collected from 114 subjects, ages 5–91, by paraffin stimulation. Samples were centrifuged and stored at –20°C for subsequent analysis. Glandular kallikrein activity was assayed usingd-ValylLeucylArginine-p-nitroanilide as the substrate. In a linear regression model which included sex, race, and age, levels only the factor of age had a significant effect on kallikrein levels. Thep-value for the reduced model including only the factor of age was 0.0406 and the R-square was 0.038. Further analysis revealed that females did exhibit significantly higher kallikrein in individuals 40 years or older and that the effect of age appeared to be limited to females. It is concluded that both gender and age must be considered when evaluating salivary kallikrein changes in relationship to systemic disease.     

Sequence Comparison of Avian Infectious Bronchitis Virus S1 Glycoproteins of the Florida Serotype and Five Variant Isolates from Georgia and California

The infectious bronchitis virus (IBV) spike glycoprotein S1 subunit is required to initiate infection and contains virus-neutralizing and serotype-specific epitope(s). Reported are the S1 gene nucleotide and predicted amino acid sequences for the Florida 18288 strain and isolates GA-92, CV-56b, CV-9437, CV-1686, and 1013. These sequences were compared with previously published gene sequences of IBV strains, and phylogenetic relationships are reported. The S1 amino acid sequence of Florida 18288 was 94.9% similar to the Connecticut strain, and GA-92 was 92.8% similar to the Arkansas 99 strain. S1 amino acid sequences of the California variants, CV-56b, CV-9437, and CV-1686, were 97.6–99.3% similar to one another and only 76.6%–76.8% similar to the Arkansas-type strains. Isolate 1013, also from California, was 84.0% similar to Ark DPI and 77.9% similar to CV-56b. When comparing 19 viruses isolated from the United States, sequence variations were observed between amino acids 55–96, 115–149, 255–309, and 378–395. Similar regions are reported to be involved in virus-neutralizing and/or serotype-specific epitopes. These data demonstrate that variant IBV strains continue to emerge, and unique variants may circulate among poultry in geographically isolated areas. This revised version was published online in July 2006 with corrections to the Cover Date.     

Malignant melanoma: analysis by DNA flow cytometry

The DNA content of 14 primary and 111 secondary melanomas was determined by flow cytometry. Aneuploidy was detected in 67% of samples. The frequency with which aneuploid cells were found was similar in primary and metastatic melanomas and, in the metastatic group, for melanotic and amelanotic tumours. Aneuploid diversity was marked with a wide variation in DNA content between tumours. Serial biopsies were performed in 14 patients, and in 10 there was discordance in DNA profiles between first and subsequent biopsies. Tumour biopsies taken from different sites at the same time also showed discordance in 3 of 5 cases. These features highlight the degree of cellular heterogeneity in malignant melanoma.     

Age-dependent effect of cholinergic lesion on dendritic morphology in rat frontal cortex

Previously, we demonstrated that plasticity of frontal cortex is altered in aging rats: 3 months after surgery, excitotoxic lesions of the nucleus basalis magnocellularis (NBM) produce larger declines in dendritic morphology in frontal cortex of aged rats relative to young adults. To determine whether the differential effect of the lesion was due specifically to loss of cholinergic input from the NBM, we assessed dendritic morphology in frontal cortex after specific cholinergic depletion in young adult, middle-aged, and aged male rats. Rats received unilateral sham or 192-IgG-saporin lesions of the NBM. Two weeks after surgery, brains were stained using a Golgi-Cox procedure. Dendritic morphology was quantified in pyramidal neurons in layers II-III of frontal cortex. Although lesions altered apical dendrites at all ages, these effects were most pronounced in aged rats. In addition, lesions produced marked atrophy of basilar dendrites in middle-aged and aged rats only. Thus, the differential dendritic atrophy resulting from NBM lesions in aged rats occurs within 2 weeks after lesion, and results specifically from loss of cholinergic innervation.     

Taurine reduces high glucose induced leukocyte–endothelial interactions via down-regulation of ICAM-1

Taurine is a semiessential amino acid and naturally occurring antioxidant. One of its main roles is to protect tissues against attack by chlorinated oxidants particularly hypochlorous acid (HOCl). It is found in high concentrations in neutrophils and previous studies showed it possesses potent antimicrobial properties and attenuates high glucose induced endothelial cell apoptosis. In humans taurine has been shown to up-regulate constitutive nitric oxide synthase (cNOS), a known cytoprotector.
No reported studies to date have looked at the possible therapeutic role of taurine in preventing diabetic endothelial dysfunction. We therefore hypothesised that taurine would attenuate the microvascular changes associated with hyperglycaemia in an animal model through alteration of leucocyte–endothelial interactions.
Male Sprague Dawley rats were randomised into control, hyperglycaemia, and taurine + hyperglycaemia groups. Taurine was gavaged (200 mg/kg) for 5 d prior to the experiment. Hyperglycaemia was established by intravenous infusion of 50% glucose. Blood glucose reached a steady state of 3 times baseline at 30 min. Using intravital microscopy leukocyte rolling, adhesion and transendothelial migration was determined in mesenteric postcapillary venules for 3 h. Intracellular adhesion molecule-1 (ICAM-1) was immunohistochemically graded using a scoring system to determine the expression in mesenteric tissue.
Taurine pretreatment significantly attenuates leukocyte-endothelial adhesion and transendothelial migration following acute hyperglycaemia but not leukocyte rolling velocity. The mechanism by which taurine protects against these effects is in part by inhibition of ICAM-1 expression .  

      

109.

The class A macrophage scavenger receptor is a major pattern recognition receptor for Neisseria meningitidis which is independent of lipopolysaccharide and not required for secretory responses     

Peiser L  De Winther MP  Makepeace K  Hollinshead M  Coull P  Plested J  Kodama T  Moxon ER  Gordon S 《Infection and immunity》2002,70(10):5346-5354

Macrophages (Mphi) play a key role in the pathogenesis of invasive meningococcal infections. The roles of two pattern recognition molecules, the Mphi scavenger receptor (SR-A) and Toll-like receptor 4 (TLR-4), have been investigated using bone marrow culture-derived Mphi (BMMphi). Surprisingly, a comparison of BMMphi from wild-type and SR-A knockout (SR-A(-/-)) mice showed that nonopsonic phagocytosis of meningococci was mediated almost exclusively via SR-A. Previous studies have demonstrated only a partial involvement of the receptor in the uptake of other bacteria, such as Escherichia coli. Interestingly, we also show that lipopolysaccharide (LPS) was not the ligand for the receptor on these organisms. Further study of the downstream events of SR-A-mediated ingestion of Neisseria meningitidis demonstrated that SR-A was not required for cytokine production. To determine the bacterial and host factors required to stimulate Mphi activation, we examined TLR-4-deficient Mphi from C3H/HeJ mice and LPS-deficient meningococci. TLR-4-deficient cells elaborated reduced amounts of tumor necrosis factor alpha, interleukin-12 (IL-12), and IL-10, even though ingestion via SR-A was unaffected in these cells. Similarly, although there was no change in SR-A-mediated ingestion of LPS-deficient meningococci, the mutant failed to stimulate a Mphi-dependent cytokine response. Thus, we show that Mphi SR-A mediates opsonin-independent uptake of N. meningitidis independently of lipid A and that this activity is uncoupled from the Mphi secretion of proinflammatory cytokines, which provides a basis for further investigation of the role of this receptor in meningococcal disease in humans.     

110.

Visual corticopontine projections in the guinea pig: an autoradiographic study     

F. Lui  Joyce Aldon 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,116(1):175-181

     

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The class A macrophage scavenger receptor is a major pattern recognition receptor for Neisseria meningitidis which is independent of lipopolysaccharide and not required for secretory responses

Macrophages (Mphi) play a key role in the pathogenesis of invasive meningococcal infections. The roles of two pattern recognition molecules, the Mphi scavenger receptor (SR-A) and Toll-like receptor 4 (TLR-4), have been investigated using bone marrow culture-derived Mphi (BMMphi). Surprisingly, a comparison of BMMphi from wild-type and SR-A knockout (SR-A(-/-)) mice showed that nonopsonic phagocytosis of meningococci was mediated almost exclusively via SR-A. Previous studies have demonstrated only a partial involvement of the receptor in the uptake of other bacteria, such as Escherichia coli. Interestingly, we also show that lipopolysaccharide (LPS) was not the ligand for the receptor on these organisms. Further study of the downstream events of SR-A-mediated ingestion of Neisseria meningitidis demonstrated that SR-A was not required for cytokine production. To determine the bacterial and host factors required to stimulate Mphi activation, we examined TLR-4-deficient Mphi from C3H/HeJ mice and LPS-deficient meningococci. TLR-4-deficient cells elaborated reduced amounts of tumor necrosis factor alpha, interleukin-12 (IL-12), and IL-10, even though ingestion via SR-A was unaffected in these cells. Similarly, although there was no change in SR-A-mediated ingestion of LPS-deficient meningococci, the mutant failed to stimulate a Mphi-dependent cytokine response. Thus, we show that Mphi SR-A mediates opsonin-independent uptake of N. meningitidis independently of lipid A and that this activity is uncoupled from the Mphi secretion of proinflammatory cytokines, which provides a basis for further investigation of the role of this receptor in meningococcal disease in humans.