The common functional C(-159)T polymorphism within the promoter region of the lipopolysaccharide receptor CD14 is not associated with sepsis development or mortality

Sepsis is characterised by a systemic inflammatory response to bacterial products during infection, which interestingly both in humans and animal models is gender associated with a higher susceptibility of males than females. The CD14 receptor is involved in activation of cells by lipopolysaccharides released from Gram-negative bacteria and, as recently shown, also by products of Gram-positive bacteria (e.g., peptidoglycans and lipoteichoic acid). The functional relevance of a C(-159)T CD14 polymorphism recently has been shown based on correlation of the T allele to higher plasma levels of soluble CD14, and higher membrane expression on monocytes. We, therefore, now analysed this CD14 polymorphism in 204 patients with severe sepsis and 247 controls. No significant difference of allele frequencies was observed between sepsis patients and controls neither for males nor females. Mortality also was not associated with the polymorphism studied. This may suggest that other mechanisms for lipopolysaccharide recognition, such as the recently described Toll-like receptors are important for inflammatory cell activation in sepsis.     

Treatment with an anti-CD18 monoclonal antibody in rabbits inhibits pneumococcal-induced leukocyte recruitment in the skin,but not in the meninges

Inflammatory recruitment of leukocytes into the cerebrospinal fluid (CSF) during bacterial meningitis has been shown to contribute to the neurological damage commonly associated with this disease. In this study we tested whether inhibition of firm leukocyte adhesion to vascular endothelium could reduce leukocyte recruitment into the subarachnoid space (SAS) and into the skin in rabbits challenged with pneumococcal cell wall (PCW) antigen. PCW was given either as an intracisternal or an intradermal (i.d.) injection. Intravenous (i.v.) treatment with a monoclonal antibody (mAb), IB4, against the leukocytic adhesion molecule CD18 has previously been documented to attenuate leukocyte CSF accumulation in experimental bacterial meningitis. In the present study, i.v. treatment with anti-CD18 mAbs (IB4) only tended to inhibit CSF leukocyte influx in animals with PCW-induced meningitis. However, if the antigen was injected i.d., treatment i.v. with the same mAb (IB4) dramatically reduced leukocyte accumulation in the skin. Our findings indicate that the mechanisms responsible for PCW-induced inflammatory accumulation of leukocytes in skin and meninges are different.     

Potentiation of human alpha4beta2 neuronal nicotinic receptors by a Flustra foliacea metabolite

The effects of various Flustra foliacea metabolites on different types of human neuronal nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes were investigated. Whereas most of the compounds tested had a small blocking effect, one of them, deformylflustrabromine, selectively increased the current obtained in alpha4beta2 receptors when co-applied with acetylcholine (ACh). The current increase was reversible and concentration-dependent. This potentiating effect was still present at saturating concentrations of acetylcholine, and no changes in single-channel conductance or reversal potential were observed, thus suggesting a modification in the gating of alpha4beta2 receptors. Dwell time analysis of single channel records indicates that the mechanism of action of deformylflustrabromine could be both an increase of the opening rate constant and a decrease of the closing rate constant on alpha4beta2 receptors. Thus, deformylflustrabromine may constitute an excellent starting point for the future development of related agents able to potentiate human neuronal nicotinic receptor function.     

Prevalence and characterization of a binary toxin (actin-specific ADP-ribosyltransferase) from Clostridium difficile

In addition to the two large clostridial cytotoxins (TcdA and TcdB), some strains of Clostridium difficile also produce an actin-specific ADP-ribosyltransferase, called binary toxin CDT. We used a PCR method and Southern blotting for the detection of genes encoding the enzymatic (CDTa) and binding (CDTb) components of the binary toxin in 369 strains isolated from patients with suspected C. difficile-associated diarrhea or colitis. Twenty-two strains (a prevalence of 6%) harbored both genes. When binary toxin production was assessed by Western blotting, 19 of the 22 strains reacted with antisera against the iota toxin of C. perfringens (anti-Ia and anti-Ib). Additionally, binary toxin activity, detected by the ADP-ribosyltransferase assay, was present in only 17 of the 22 strains. Subsequently, all 22 binary toxin-positive strains were tested for the production of toxins TcdA and TcdB, toxinotyped, and characterized by serogrouping, PCR ribotyping, arbitrarily primed PCR, and pulsed-field gel electrophoresis. All binary toxin-positive strains also produced TcdB and/or TcdA. However, they had significant changes in the tcdA and tcdB genes and belonged to variant toxinotypes III, IV, V, VII, IX, and XIII. We could differentiate 16 profiles by using typing methods, indicating that most of the binary toxin-positive strains were unrelated.     

The regulatory role of FSH in steroid formation by luteinized human granulosa cells in culture

Granulosa cells were aspirated from human pre-ovulatory folliclesfollowing a combined clomiphene-gonadotrophin stimulation inan in-vitro fertilization (IVF) programme. The cells were culturedfor 8 days in medium M199 containing 10% bovine fetal calf serumunder 5% CO₂ in air. Pure human FSH and human LH were addedalone or in combination to the culture in various concentrationsand the progesterone (P) and oestradiol-17 (E₂) levels in themedium were measured every second day by a conventional RIAtechnique. In the presence of FSH or LH the formation of P increased2- to 3-fold with the pronounced effect after 4 to 6 days inculture. Addition of testosterone (T) (3 ? 10^–7 M) tothe culture medium affected neither basal nor gonadotrophinstimulated P formation. In this system, only minute amountsof E₂ were formed and neither FSH nor LH stimulated its formation.When the medium was fortified with T, basal E₂ formation increased50- to 100-fold. FSH further stimulated this conversion significantlyafter 6 and 8 days of culture, while LH had no significant influence.     

Improvement in histological diagnosis of primary hyperparathyroidism with a monoclonal antiparathyroid antibody

The monoclonal antiparathyroid antibody E11 reacts with a glycoprotein of high molecular weight, which acts as a calcium receptor on the surface of parathyroid cells and mediates calcium regulation of parathyroid hormone (PTH) release. Reduced expression of the calcium receptor has been implicated as a cause of the defect in PTH regulation in the pathological parathyroid parenchyma of patients with hyperparathyroidism (HPT). The present study evaluated the efficacy of immunostainings with the E11 antibody in comparison with routine histopathological methods including staining by the oil red O technique for histological discrimination between normal and pathological parathyroid glands. Parathyroid tissue from euparathyroid individuals invariably presented intense and homogeneous surface staining, with the antibody on virtually all chief cells, while the pathological glands from patients with HPT consistently showed heterogeneous and reduced immunostaining. Even minimally enlarged pathological glands from individuals with mild hypercalcemia and the normal-sized glands associated with adenomas displayed parathyroid chief cells with reduced antibody reactivity. The monoclonal antiparathyroid antibody should constitute a useful tool in parathyroid histopathology not only by its ability to identify the parathyroid tissue, but also by directly demonstrating the functionally normal and abnormal cells within the parathyroid tissue.     

Characterization of an IgA receptor from group B streptococci: specificity for serum IgA

Some strains of group B streptococci express a cell surface protein which binds IgA. This report describes some properties of such an IgA receptor and compares it with a previously described IgA receptor from group A streptococci. The group B receptor was released in an almost pure form from bacteria incubated at elevated pH, and could be isolated by IgA-Sepharose affinity chromatography. The sequence of the N-terminal 19 amino acid residues was unique. The receptor preferentially binds IgA of human origin, as shown in immunoblotting experiments with purified IgA from nine different species. The affinity constant of the purified receptor for serum IgA was determined to be 3.5 x 10(8) M-1, but for secretory IgA it was too low to allow determination. This result indicates that secretory component and/or J chain interferes with the binding of IgA to this type of bacterial receptor, which may be one of the physiological functions of these polypeptides. A reduction in affinity was also observed for another complexed form of IgA, alpha 1-microglobulin-IgA. The group B receptor is antigenically unrelated to the IgA receptor from group A streptococci (protein Arp), but competitive inhibition experiments indicate that they bind to the same region in IgA. The implications of these findings, and the biological role of bacterial IgA receptors, are discussed.     

Variations in attachment ofNeisseria gonorrhoeae to vaginal epithelial cells during the menstrual cycle and early pregnancy

An in vitro system was used to study the ability of virulent gonococci to adhere to vaginal epithelial cells obtained from healthy donors during the pre- and postmenstrual phases, and from those in early pregnancy. It was found that more gonococci adhered to the cells from donors in the postmenstrual phase than to cells from those in the premenstrual one. This difference was statistically highly significant. The attachment rate of gonococci to vaginal epithelial cells was similar in early pragnancy and in the premenstrual phase.     

No association between schizophrenia and homozygosity at the D3 dopamine receptor gene

The D₃ dopamine receptor gene is an important candidate gene for schizophrenia, since (because of its almost exclusive expression in the limbic system) it combines the dopamine receptor hypothesis with the limbic system hypothesis of schizophrenia. A BalI restriction fragment length polymorphism of the D₃ dopamine receptor gene has been typed in 107 schizophrenic patients and 98 normal controls from Sichuan (China). With regard to alleles or genotypes, no significant differences were obtained between controls from Europe and China, between patients and controls, and between patient subgroups and controls. These results indicate a lack of association between schizophrenia and the D₃ dopamine receptor gene in our sample. Our findings are at variance with reports of a significant excess of homozygosity at the D₃ dopamine receptor gene in schizophrenic patients from Wales (United Kingdom) and Alsace (France). In conclusion, further studies will be needed with larger samples of patients from Wales and Alsace as well as with samples of different racial groups to prove or disprove the initial positive association between schizophrenia and genotypes of the D₃ dopamine receptor gene. © 1993 Wiley-Liss, Inc.