Identification and characterization of epitopes on Cyn d I, the major allergen of Bermuda grass pollen

BACKGROUND: We identified three epitopes on Cyn d I by using four anti-Cyn d I monoclonal antibodies (MoAbs). METHODS: In a cross-inhibition binding assay, the binding of MoAbs 1-61 and 10-7 to Cyn d I was completely blocked by each other but not by MoAbs 4-37 and 11-7; the binding of MoAb 4-37 and MoAb 11-7 to Cyn d I was inhibited by themselves but not by other MoAbs. The epitope recognized by MoAbs 1-61 and 10-7 is designated as E1, and those recognized by MoAbs 4-37 and 11-7 are designated as E2 and E3, respectively. RESULTS: In a radioallergosorbent inhibition assay, we found that MoAbs 1-61 and 4-37 (1:50 diluted) can inhibit the binding of human Immunoglobulin Es to Cyn d I by more than 30%, whereas MoAb 11-7 was less efficient (reduced by only 6%). These results suggest that both E1 and E2 are major allergenic epitopes but that E3 is only a minor one. Further characterization of E1 and E2 reveals that they are labile in alkaline but resistant to acid and sodium periodate treatments. Moreover, E1 is heat-labile, but guanidine- and urea-sensitive, whereas E2 is not. Both E1 and E2 lost their antigenicity after reduction and alkylation. CONCLUSIONS: Results of the present study provide important information on the physicochemical properties of major allergenic epitopes on Cyn d I, which may be useful for future development of therapeutic peptides for patients allergic to Bermuda grass pollen.     

Perinatal transmitted acute icteric hepatitis B in infants born to hepatitis B surface antigen-positive and anti-hepatitis Be-positive carrier mothers

Three infants born to mothers who were hepatitis B surface antigen (HBsAg) positive and had antibody to hepatitis Be antigen (anti-HBe), developed acute icteric hepatitis B within three months of birth. All three infants clinically recovered and developed circulating anti-HBs. Contrary to previous studies, these three cases indicate that mother-infant transmission of the hepatitis B virus (HBV) does occur in infants born to HBsAg-positive, HBe-Ag-negative carrier mothers, and these infants may develop severe acute icteric hepatitis. Therefore, immunoprophylaxis in such newborns may be indicated.     

Diffuse interstitial pneumopathy associated with limited Sj?gren's syndrome (author's transl)

Diffuse interstitial pneumopathy was found to be associated with limited Sj?gren's syndrome (i.e. without connective tissue involvement) in 5 women aged from 48 to 83 years. The respiratory symptoms (dyspnoea, unproductive cough and crepitations) appeared before the dry-eye-and-mouth syndrome was diagnosed in two patients and several years afterwards in three. Respiratory function studies showed a mixed restrictive and obstructive syndrome, perturbed Co transfer and increased total expiratory airways resistance. These changes reflected the underlying pathology, as revealed by bronchial and lung biopsies, which consisted of lymphocyte and plasmocyte infiltration and fibrosis of the interalveolar septa, peribronchial spaces and bronchial glands. Abnormal respiratory function tests in 5 other patients without any respiratory symptom suggest that subclinical and subradiological lesions of the lungs and bronchi are not uncommon in Sj?gren's syndrome.     

Molecular mimicry accompanying HIV-1 infection: human monoclonal antibodies that bind to gp41 and to astrocytes

Monoclonal antibodies that bound to HIV gp41 and cross-reacted with astrocytes were recovered from the blood of three patients infected with HIV-1. Mapping of the specificity of these monoclonal antibodies, using synthetic gp41 peptides, located their epitope to amino acids 644-663 and established their conformation dependence. Six other human monoclonal anti-HIV antibodies were found to bind to HIV gp41 or gp120 but not to reactive astrocytes in brain tissue. Sharing of linear or conformational protein determinants between disparate viral and host proteins is termed molecular mimicry. The consequences of such mimicry by anti-viral antibodies interacting with astrocytes may play a role in the dementia of AIDS patients since a major function of astrocytes is to maintain the appropriate milieu for neuronal function. The finding of such cross-reactive antibodies adds to the evidence for a possible autoimmune pathogenesis in some of the disease manifestations accompanying HIV infection.     

An evaluation of clinical laboratory services in sub-Saharan Africa. Ex africa semper aliquid novi?

Pathology services represent the rational, scientific basis of the practice of clinical care. It does not represent deus ex machina, an implausible solution to a complex plot, but rather the way in which clinical care can be audited, controlled, guided and kept appropriate to the funds and the skills available. Arguments are presented to support this statement as well as to analyse what is wrong with health care, from the point of view of laboratory medicine, in sub-Saharan Africa. In most African countries 'first world' technology has to be imported by economies barely able to sustain the basic requirements of human life. Badly needed foreign exchange is obtained by growing export crops at the cost of traditional lifestyle, disenfranchising communities, urbanisation, and even at the cost not being able to grow food. War, corruption, lack of accountability even in the Western sense of being able to go to the polls every so often, lack of empowerment, low literacy rate etc all debase the communities, with minimal exceptions, of Africa. Health care is under the same capricious rule as all other public services: investment in laboratories is poor and most have no access to a professional laboratory at all. More investment, not less; expansion of pathology services not restricting them, is needed throughout the continent.     

Influence of alleles of apolipoprotein E on restenosis after coronary angioplasty in women

Galanin is a 29-amino acid peptide and widely distributed in the brain, although its significance in the control of neural activities is undefined. In the present study, we describe the effects of galanin on the electrically evoked release of dopamine in the rat central nervous system. In addition, to elucidate a possible role of galanin in the regulation of dopaminergic transmission in hypertension, we examined whether the effect of galanin on dopamine release might be altered in the central nervous system of spontaneously hypertensive rats (SHR). Galanin (1 x 10(-8) to 1 x 10(-7) mol/L) inhibited the stimulation (1 Hz)-evoked [3H]dopamine release by a comparable amount in striatal slices of Sprague-Dawley rats, although the basal release of dopamine was not affected by the peptide. In the striatum of SHR, the electrical stimulation (1 Hz)-evoked [3H]dopamine release was significantly smaller than in the striatum of Wistar-Kyoto (WKY) rats. However, the inhibitory effect of galanin on the stimulation-evoked [3H]dopamine release was significantly more pronounced in SHR than in WKY rats. These results show that galanin significantly reduced the release of dopamine in rat striatum. Furthermore, the greater inhibitory effect of galanin on dopamine release in SHR suggests that galanin might actively participate in the regulation of dopaminergic nerve activity in hypertension.     

Synergistic cooperation between phorbol ester and IFN-gamma for induction of nitric oxide synthesis in murine peritoneal macrophages

The role of protein kinase C (PKC) in the induction of nitric oxide (NO) synthesis in murine peritoneal macrophages was examined. Phorbol ester, a PKC activator, had no effect on NO synthesis by itself, whereas IFN-gamma alone had modest activity. When phorbol ester was used in combination with IFN-gamma, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. This increase in NO synthesis was reflected as increased amount of inducible NO synthase (iNOS) mRNA, as determined by Northern blotting. The optimal effect of phorbol ester was shown at 6 h after treatment with IFN-gamma. Phorbol ester also induced the release of NO to the incubation medium by bacillus Calmette-Guerin-infected peritoneal macrophages. Prolonged incubation of cells with phorbol ester, which down-regulates PKC activity, abolished the synergistic cooperative effect on NO production with IFN-gamma. In addition, such PKC inhibitors as staurosporin or polymyxin B reduced NO production induced by IFN-gamma plus phorbol ester. When the cells were treated with both actinomycin D and phorbol ester after IFN-gamma stimulation, more NO was produced and more iNOS mRNA was expressed than in the cells treated with actinomycin D alone. On the basis of these observations, we conclude that PKC might not be directly involved in the expression of NO synthase, but, instead, might be involved in the stabilization of the iNOS mRNA already expressed by the treatment of IFN-gamma.     

Mechanism of regulation of 8-hydroxyguanine endonuclease by oxidative stress: roles of FNR, ArcA, and Fur

We found previously that 8-hydroxyguanine (oh8Gua) endonuclease in E. coli is induced in response to oxidative stress in a fashion similar to the oxidative response of the Mn-superoxide dismutase (MnSOD). In this study, attempts were made to identify the genes involved in the co-regulation of E. coli endonuclease and MnSOD (sodA). oh8Gua nuclease is induced by molecular oxygen and a superoxide radical generator (paraquat) but not by H2O2, suggesting that the regulation of this endonuclease is dependent on SoxRS but independent of OxyR. This enzyme was induced by paraquat in all of the soxRS mutant strains used (soxR-, soxS- and soxRc), whereas glucose-6-phosphate dehydrogenase (a member of the soxRS regulon) showed the expected responses; therefore, this possibility was excluded. The presence of metal chelators in the growth medium caused the induction of this enzyme, and this induction was suppressed by the addition of Fe++. Consistent with this finding, this enzyme was expressed under anaerobiosis in all of the mutant strains of fnr in particular, as well as fur, arcA, and combinations thereof. These findings suggest that the oxidative regulation of oh8Gua endonuclease is under control of fnr, fur, and arcA, where fnr plays a predominant role. The multiple involvement of regulatory genes as well as co-regulation with antioxidant enzyme will enhance the efficiency of cellular growth and survival in the aerobic environment.