Participation of immunoglobulins and complement components in the intracellular killing of Staphylococcus aureus and Escherichia coli by human granulocytes.

Immunoglobulins and complement components are required for optimal ingestion and optimal killing of microorganisms by granulocytes. The degree of opsonization of microorganisms necessary for their ingestion was lower than that required for the killing of these bacteria during the ingestion phase. Killing during this phase was found to depend mainly on the presence of heat-labile opsonins, probably C3b, present on the microorganisms. Extracellular immunoglobulin G (IgG) and C3b were indispensable for optimal intracellular killing after ingestion was complete. This was established with an assay permitting assessment of the course of the number of viable intracellular bacteria independent of the ingestion of new live bacteria. Maximal intracellular killing by human granulocytes of ingested catalase-positive (Staphylococcus aureus and Escherichia coli) or catalase-negative (Streptococcus pyogenes and S. pneumoniae) microorganisms was found only when fresh serum was present extracellularly. Killing was suboptimal in the absence of serum. With heat-inactivated serum, the killing index lay between the indices obtained in the presence and absence of fresh serum. The stimulatory activity of heat-inactivated serum was most probably due to the interaction of IgG with the Fc receptor on the granulocyte membrane, since IgG subclasses IgG1 and IgG3 as well as pFc fragments of IgG stimulated the intracellular killing to the same degree as heat-inactivated serum did. In addition, (Fab1)2 fragments of IgG did not stimulate killing, and reduced killing was observed in the presence of heat-inactivated serum after reduction of the number of Fc receptors. The extra stimulation of the killing process in the presence of fresh serum compared with heat-inactivated serum was due to the interaction between membrane receptors and complement--most probably C3b generated by both the classical and the alternative pathways of complement activation. This conclusion is based on results obtained with sera in which one or both complement pathways were blocked, on the restoration of the killing-stimulatory activity of C3-deficient serum after addition of fresh C3, and on the reduced killing observed in the presence of fresh serum after reduction of the number of C3 receptors by the use of pronase or antigranulocyte serum.     

A 2-year, randomized, comparative, placebo-controlled study on the effects of raloxifene on lipoprotein(a) and homocysteine

OBJECTIVES: Lipoprotein(a) (Lp(a)) and homocysteine (Hcy) are independent cardiovascular risk factors, which have been shown to be lowered by hormone replacement therapy (HRT). In this 2-year study, the long-term effects of raloxifene (Rlx) in two doses, on Lp(a) and Hcy, were studied and compared with the effects of continuously combined hormone replacement therapy (ccHRT). METHODS: In a prospective, randomized, double-blind, placebo-controlled 2-year study, 95 healthy, non-hysterectomized, early postmenopausal women, received daily either oral Rlx 60 mg (N=24) or 150 mg (N=23), ccHRT (conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 2.5 mg; N=24) or placebo (N=24). Fasting serum Lp(a) and plasma Hcy concentrations were measured at baseline and at 6, 12 and 24 months. RESULTS: The mean individual changes compared to baseline after 24 months were for Lp(a): Rlx 60: - 5%, Rlx 150: -7%, ccHRT: -34%, placebo: +1% and for Hcy: Rlx 60: -3%, Rlx 150: -4%, ccHRT: -4%, placebo: +6%. ANCOVA was significant for Lp(a) under ccHRT versus placebo (P=0.001) and for Lp(a) under ccHRT versus each of the two Rlx groups (P<0.05). CONCLUSIONS: Long-term treatment with Rlx was not as effective as ccHRT in lowering Lp(a). Although not significant and without an obvious dose-related response, the Hcy values showed the same trend for each treatment arm, which is in line with data reported earlier.     

Effective in vitro clearance of Porphyromonas gingivalis by Fc alpha receptor I (CD89) on gingival crevicular neutrophils

Porphyromonas gingivalis has been implicated as a causative pathogen in periodontitis. Immunotherapeutic approaches have recently been suggested to aid in the clearance of P. gingivalis from disease sites. Because antibody-Fc receptor (FcR) interactions play a role in the effector functions of polymorphonuclear neutrophils (PMN), we evaluated which FcR on PMN from gingival crevicular fluid (GCF) serves as an optimal target molecule for FcR-directed immunotherapy. GCF PMN and peripheral blood (PB) PMN from adult periodontitis patients were analyzed for their immunoglobulin G (IgG) and IgA FcR (Fc gamma R and Fc alpha R, respectively) expression and function by studying IgG- and IgA-mediated elimination of P. gingivalis. GCF PMN exhibited higher Fc alpha RI and Fc gamma RI levels and lower Fc gamma RIIa and Fc gamma RIIIb levels than PB PMN. Functional studies revealed that GCF PMN exhibited less of a capacity to phagocytose and kill IgG1-opsonized P. gingivalis than PB PMN. IgA1-mediated phagocytosis and killing capacity was, however, comparable between GCF PMN and PB PMN. In summary, these in vitro results document that Fc alpha RI represents a candidate target for FcR-directed immunotherapy for the clearance of P. gingivalis.     

Predicting Emotional Response to Unsuccessful Fertility Treatment: A Prospective Study

The predictive value of a comprehensive model with personality characteristics, stressor related cognitions, coping and social support was tested in a sample of 187 nonpregnant women. The emotional response to the unsuccessful treatment was predicted out of vulnerability factors assessed before the start of the treatment. The results indicated the importance of neuroticism as a vulnerability factor in emotional response to a severe stressor. They also underlined the importance of helplessness and marital dissatisfaction as additional risk factors, and acceptance and perceived social support as additional protective factors, in the development of anxiety and depression after a failed fertility treatment. From clinical point of view, these results suggest fertility-related cognitions and social support should receive attention when counselling women undergoing IVF or ICSI treatment.     

Toward Improving Caenorhabditis elegans Phenome Mapping With an ORFeome-Based RNAi Library

The recently completed Caenorhabditis elegans genome sequence allows application of high-throughput (HT) approaches for phenotypic analyses using RNA interference (RNAi). As large phenotypic data sets become available, “phenoclustering” strategies can be used to begin understanding the complex molecular networks involved in development and other biological processes. The current HT-RNAi resources represent a great asset for phenotypic profiling but are limited by lack of flexibility. For instance, existing resources do not take advantage of the latest improvements in RNAi technology, such as inducible hairpin RNAi. Here we show that a C. elegans ORFeome resource, generated with the Gateway cloning system, can be used as a starting point to generate alternative HT-RNAi resources with enhanced flexibility. The versatility inherent to the Gateway system suggests that additional HT-RNAi libraries can now be readily generated to perform gene knockdowns under various conditions, increasing the possibilities for phenome mapping in C. elegans.     

Evaluation of an internally controlled real-time polymerase chain reaction assay targeting the groEL gene for the detection of Bartonella spp. DNA in patients with suspected cat-scratch disease

Bartonella (B.) henselae is the causative agent of cat-scratch disease (CSD), which usually presents as a self-limiting lymphadenopathy. This study reports the development and evaluation of an internally controlled real-time polymerase chain reaction targeting the groEL gene for detection of Bartonella spp. DNA was extracted using the MagNA Pure system. The lower detection limit was 10–100 fg DNA and the in vitro sensitivity of the assay was not affected by duplexing with an internal control PCR. The real-time PCR assay detected DNA from all five B. henselae strains tested, and from B. birtlesii, B. vinsonii subsp. vinsonii, B. vinsonii subsp. arupensis and B. doshiae. The assay generated negative results with a selection of other bacteria, including several Mycobacterium spp., Streptococcus pyogenes and Staphylococcus aureus. Results of real-time PCR in clinical samples were compared with those of a conventional 16S rDNA-based PCR assay. During the period described in the Material and methods section, real-time PCR and conventional 16S PCR were performed on 73 clinical samples. Of these samples, 29 (40%) were found to give positive results and 44 (60%) gave negative results, both by real-time PCR and by conventional PCR, with a 100% agreement between the two tests. The PCR developed in this study is a rapid, sensitive, and simple method for the detection of Bartonella spp. in CSD and is suitable for implementation in the diagnostic laboratory.     

Detection of K-ras mutations in mucinous pancreatic duct hyperplasia from a patient with a family history of pancreatic carcinoma.

Mutations in the K-ras oncogene and in the p53 tumor suppressor gene are commonly identified in sporadic cases of pancreatic adenocarcinoma. Although these genes might serve as useful markers for early diagnosis of pancreatic carcinoma in patients at risk for the development of this disease, familial pancreatic carcinomas have not been studied for these mutations. We recently had the opportunity to examine a pancreas prophylactically removed from a patient with a strong family history of pancreatic carcinoma. This gave us the unique opportunity to study the early events in the development of familial adenocarcinoma of the pancreas. Histopathological examination of the pancreas revealed multifocal papillary and nonpapillary mucinous duct hyperplasia. Seven of these foci were microdissected and analyzed for K-ras and p53 mutations. The K-ras mutations were detected by combined mutant-enriched polymerase chain reaction-restriction fragment length polymorphism analysis and characterized further by allele-specific oligonucleotide hybridization. Five of the seven duct lesions harbored activating point mutations in codon 12 of K-ras; a G to A transition was found in four and a G to C transversion in one. In contrast, these lesions did not harbor detectable p53 mutations as determined by denaturing gradient gel electrophoresis of exons 5 to 8, nor was there overexpression of the p53 protein as determined by immunohistochemistry. These findings suggest that mutations in K-ras represent an early event in the pathogenesis of pancreatic carcinoma. In addition, monitoring of patients with a strong family history of pancreatic carcinoma for K-ras mutations may identify patients at risk for the development of invasive carcinoma.     

Use of various genetic markers in differentiation of Mycobacterium bovis strains from animals and humans and for studying epidemiology of bovine tuberculosis.

One hundred fifty-three Mycobacterium bovis strains from cattle, various animal species from zoos and wild parks, and humans were analyzed for three different genetic markers for use in the epidemiology of bovine tuberculosis. M. bovis strains isolated from cattle were found to carry a single IS6110 element, whereas the majority of strains from other animals such as antelopes, monkeys, and seals harbored multiple IS6110 elements, suggesting that the reservoirs in cattle and wild animals are separated. Because the single IS6110 element in cattle strains is located at the same chromosomal position, strain differentiation by insertion sequence fingerprinting was hampered. Therefore, we investigated the usefulness of the direct repeat and polymorphic GC-rich repeat elements for strain differentiation. Both markers allowed sufficient strain discrimination for epidemiological purposes. Evidence is presented that in Argentina, most human M. bovis infections are due to transmission from cattle, whereas M. bovis infections among humans in the Netherlands are mainly contracted from animals other than cattle. Various outbreaks of M. bovis among animals and humans are described, including a small one which likely involved transmission from human to human.     

Endogenous tumor necrosis factor alpha is required for enhanced antimicrobial activity against Toxoplasma gondii and Listeria monocytogenes in recombinant gamma interferon-treated mice.

In vitro studies have shown that macrophages stimulated with recombinant gamma interferon (rIFN-gamma) produce tumor necrosis factor alpha (TNF-alpha), which in an autocrine fashion activates these cells. The aim of the present study was to determine whether endogenously formed TNF-alpha also is required for rIFN-gamma-induced macrophage activation and enhanced antimicrobial activity in vivo. After an intraperitoneal injection of rIFN-gamma into CBA/J mice, their peritoneal macrophages released enhanced amounts of NO2- and inhibited the intracellular proliferation of Toxoplasma gondii. Injection of neutralizing antibodies against TNF-alpha simultaneously with the rIFN-gamma completely inhibited both the release of NO2- by macrophages and their toxoplasmastatic activity. Similar results were observed after intraperitoneal injection of a competitive inhibitor of L-arginine, NG-monomethyl-L-arginine, together with rIFN-gamma, demonstrating that in vivo L-arginine-derived reactive nitrogen intermediates are essential for the induction of toxoplasmastatic activity. Intravenous injection of rIFN-gamma inhibited the growth of Listeria monocytogenes in the livers and spleens of mice; this effect was abrogated by antibodies against TNF-alpha. Intravenous injection of a large dose of rTNF-alpha resulted in a decrease in the number of bacteria in the liver and spleen, but an injection of rIFN-gamma and rTNF-alpha did not result in enhanced inhibition of the proliferation of L. monocytogenes. Together, the results of the present study are the first to demonstrate that endogenous TNF-alpha is required in vivo for the expression of macrophage activation with respect to the release of reactive nitrogen intermediates and toxoplasmastatic activity and for enhanced listericidal activity in the livers and spleens of mice stimulated with rIFN-gamma.     

Urogenital Chlamydia trachomatis serovars in men and women with a symptomatic or asymptomatic infection: an association with clinical manifestations?

To determine whether certain Chlamydia trachomatis serovars are preferentially associated with a symptomatic or an asymptomatic course of infection, C. trachomatis serovar distributions were analyzed in symptomatically and asymptomatically infected persons. Furthermore, a possible association between C. trachomatis serovars and specific clinical symptoms was investigated. C. trachomatis-positive urine specimens from 219 asymptomatically infected men and women were obtained from population-based screening programs in Amsterdam. Two hundred twenty-one C. trachomatis-positive cervical and urethral swabs from symptomatically and asymptomatically infected men and women were obtained from several hospital-based departments. Serovars were determined using PCR-based genotyping, i.e., restriction fragment length polymorphism analysis of the nested-PCR-amplified omp1 gene. The most prevalent C. trachomatis serovars, D, E, and F, showed no association with either a symptomatic or asymptomatic course of infection. The most prominent differences found were (i) the association of serovar Ga with symptoms in men (P = 0.0027), specifically, dysuria (P < 0.0001), and (ii) detection of serovar Ia more often in asymptomatically infected people (men and women) (P = 0.035). Furthermore, in women, serovar K was associated with vaginal discharge (P = 0.002) and serovar variants were found only in women (P = 0.045).