Rapid detection of Candida albicans in clinical blood samples by using a TaqMan-based PCR assay

We describe a rapid and reproducible PCR assay for quantitation of the Candida albicans ribosomal DNA (rDNA) in clinical blood samples based on the TaqMan principle (Applied Biosystems), in which a signal is generated by cleavage of a template-specific probe during amplification. We used two fluorogenic probes based on universal, fungus-specific primers, one for the detection of C. albicans species DNA and one for the detection of all Candida genus DNA. C. albicans blastoconidia mixed with whole blood in a titration experiment yielded a linear PCR signal over a range of 3 orders of magnitude. The TaqMan-based PCR assay for C. albicans exhibited a low limit of detection (5 CFU/ml of blood) and an excellent reproducibility (96 to 99%). While the C. albicans species-specific probe had 100% specificity for C. albicans, all Candida genus-specific probes cross-reacted with other organisms likely to coinfect patients with C. albicans infections. On the basis of these data, we determined the C. albicans loads with a species-specific probe from 122 blood samples from 61 hematology or oncology patients with clinically proven or suspected systemic Candida infections. Eleven positive samples exhibited a wide range of C. albicans loads, extending from 5 to 100,475 CFU/ml of blood. The sensitivity and specificity of the present assay were 100 and 97%, respectively, compared with the results of blood culture. These data indicate that the TaqMan-based PCR assay for quantitation of C. albicans with a species-specific probe provides an attractive alternative for the identification and quantitation of C. albicans rDNA in pure cultures and blood samples.     

Compositional and structural analysis of PELA biodegradable block copolymers degrading under in vitro conditions

This paper describes an investigation of the in vitro degradation of some polyethylene oxide/polylactic acid block copolymers. It has been found that the faster the degradation, the more basic the incubation medium and, as expected, the higher the temperature. The addition of enzyme proved to have no effect. This study shows that some polyethylene oxide/polylactic acid copolymers exhibit a steady increase in polylactic acid content, as degradation proceeds. This behaviour was attributed to the solubilization effect of the hydrophilic polyethylene oxide chains on the extraction of polyethylene oxide/polylactic acid-degrading fragments. Our findings indicate that polylactic acid blocks are cleaved randomly, the lactoyl end unit playing no special role. In accordance with data published for other biodegradable polymers, the crystallinity of polyethylene oxide/polylactic acid increases as degradation proceeds.     

IL-4 production by human polymorphonuclear neutrophils

Polymorphonuclear neutrophils (PMN) are phagocytic cells, able to secrete a large range of cytokines, including inflammatory cytokines, chemokines, as well as the Th1 cytokines interferon-gamma (IFN-gamma) and interleukin (IL)-12. Although PMN do not seem to express IL-10 and IL-13, no information exists on the ability of PMN to produce IL-4. Therefore intracellular flow cytometry was performed in the presence or absence of Brefeldin A. Similarly to eosinophils, freshly isolated neutrophils from normal donors contained low amounts of IL-4, which significantly increased upon culture with Brefeldin A (P < 0001). Immunostaining performed on cytospin preparations of normal granulocytes confirmed the presence of intracellular IL-4. Using a highly sensitive ELISA, the levels of IL-4 secreted by cultured PMN and peripheral blood mononuclear cells (PBMC) were compared. PBMC secrete up to 60 times more IL-4 as PMN but, in the presence of calcium ionophore, only PMN showed a slight but significant increase in IL-4 secretion (P < 0.05). In conclusion, we report here the presence within human PMN of intracellular IL-4, which can at least partly be released under calcium ionophore stimulation. The relevance of this production of IL-4 by human PMN is discussed.     

Hepatitis B vaccination and central nervous system demyelination: an immunological approach

Demyelination events or multiple sclerosis following hepatitis B virus (HBV) vaccination have been reported. We therefore compared the T-cell response to HBsAg in patients with CNS demyelination following HBV vaccination and in HBV-vaccinated healthy individuals. Our data showed no differences in terms of T-cell proliferation or cytokine production between these groups and may help to allay concerns that HBV vaccination might trigger a deleterious immune response.     

Mechanisms of peptide YY release induced by an intraduodenal meal in rats: neural regulation by proximal gut

 Peptide YY (PYY) release in anaesthetized rats was studied during the 2 h following the intraduodenal administration of a semi-liquid meal of 21 kJ. Surgical and pharmacological manipulations were performed in order to analyse the mechanisms of PYY release. Postprandial PYY release was suppressed or strongly decreased by caecocolonectomy, truncal vagotomy, tetrodotoxin, hexamethonium, sensory denervation by perivagal capsaicin, and by the NO-synthase inhibitor L-N-arginine methyl ester, while atropine, adrenergic blockers, antagonists of type-A or type-B cholecystokinin (CCK) receptors or bombesin receptors had no effect. Comparing the digestive transit of the semi-liquid meal with the amount of PYY contained in the small bowel wall showed that nutrients had not reached the area rich in cells containing PYY by 30 min, the time at which there was a large PYY release in plasma. By 120 min, the meal front had travelled 72% of the small intestine length, just beginning to reach the PYY-rich part of the ileum. We conclude that the main postprandial PYY release studied in this model comes from ileal and colonic L-cells indirectly stimulated through a neural mechanism originating in the proximal gut and involving sensory vagal fibres, nicotinic synapses and NO release, while CCK and bombesin do not seem to be physiologically involved. Received: 17 July 1996 / Received after revision: 11 October 1996 / Accepted: 18 October 1996     

The role of the pontis oralis in the generation of RSA activity in the hippocampus of the guinea pig

The relationship between field activity in the nucleus pontis oralis (PnO) and the hippocampus was examined in the guinea pig. Rhythmical slow activity (RSA or theta activity) could be recorded from both the pontis oralis and the hippocampus. RSA recorded in the pontis oralis was of the same principal frequency as that found in the hippocampus, but had a much lower amplitude. Behavioral correlates of PnO RSA were the same as the behavioral correlates of hippocampal RSA. The effects of atropine sulfate on RSA were the same at each site. Stimulation of the PnO produced RSA in the hippocampus. Lesions of the PnO had no effect on RSA recorded from the hippocampus or on the behavioral correlates of this RSA. Lesions of the medial septum abolished RSA in both sites. Cross-correlations between field activity recorded from both the hippocampus and PnO showed the same time lag before and after septal lesions. These results indicate that while the PnO is not instrumental in the production of hippocampal RSA, an intact septum is necessary for the production of RSA in both sites. They also indicate that there is a common projection to these sites which does not pass through the medial septum.     

Involvement of the catecholaminergic system in glucagon-induced thermogenesis in Muscovy ducklings (Cairina moschata)

Physiological studies have shown that glucagon is a potential mediator of nonshivering thermogenesis (NST) in birds. The present work was undertaken in order to investigate whether the observed thermogenesis results from a direct action of glucagon on avian thermoregulatory mechanisms or in fact requires the participation of other agents such as catecholamines. Our experiments were performed using cold-acclimated (CA) ducklings which developed muscle NST. A comparison was made with thermoneutral (TN) ducklings of the same age. Our principal results showed that: (1) at ambient temperature (25 degrees C), circulating norepinephrine (NE) was markedly decreased in CA ducklings (-42%), while circulating epinephrine (E) did not undergo any consistent change; (2) in CA and TN ducklings, an intraperitoneal injection of glucagon (360 microg x kg(-1)) was followed after 10 min by prominent lipolysis and a large increase in circulating NE (4- to 6-fold) and E (14- to 17-fold), which was sustained for at least 1 h. The elevation of circulating NE was less pronounced in CA ducklings. The thermogenic action of glucagon in birds is probably indirect and involves at least the mobilization of lipids and sympatho-adrenal stimulation. The changes in peripheral noradrenergic activity during cold acclimation could be associated with adaptive changes leading to NST.     

Rectal syphilis mimicking histiocytic lymphoma

Homosexuality is being recognized with increasing frequency in the United States, and the physician must be knowledgeable of the presentations of venereal infection in this population. A 23-year-old man who denied homosexuality presented with a rectal mass and diffuse adenopathy. Biopsy of the mass was interpreted as histiocytic lymphoma. Subsequent serology had positive results for syphilis. Further questioning revealed a history of anorectal intercourse, and special stains of the mass revealed spirochetes. Syphilis must be considered in any young patient presenting with a rectal mass, regardless of the biopsy histologic characteristics or sexual history.     

Long-term follow-up of the Indiana conservative resurfacing hip arthroplasty

Sixty-four Indiana conservative (Depuy, Warsaw, IN) hip arthroplasties performed in 61 patients were reviewed for loosening, mechanisms of loosening, and revision rate. Mean follow-up time was 6.8 years. There were revisions in 26 hips (40.6%) with 4 hips awaiting revision, yielding a total of 30 hips (47%) defined as failures. Acetabular failure occurred in 20 hips, femoral failure in 18, and combined failure in 13. Failure of this prosthesis persists over time. There seems to be little or no place for this design in contemporary hip joint arthroplasty.