Towards a definition of aspirin resistance: a typological approach

'Aspirin resistance' is a poorly defined term to describe the inability of aspirin to protect individuals from thrombotic complications and there are conflicting reports on incidence rates and clinical relevance of this phenomenon. Using collagen (1 microg/ml)-induced platelet aggregation and thromboxane formation (measured as thromboxane B(2)) in citrated platelet-rich plasma, this study demonstrates that aspirin resistance can be classified into three distinct types. In aspirin responders, both, collagen-induced platelet aggregation and thromboxane formation was completely (>95%) inhibited by oral aspirin treatment (100 mg/day). In type I resistance (pharmacokinetic type), oral treatment with aspirin was ineffective but addition of aspirin (100 microM) in vitro resulted in a complete inhibition of collagen-induced platelet aggregation and thromboxane formation. In type II resistance (pharmacodynamic type), neither oral treatment with aspirin nor addition of aspirin in vitro inhibited collagen-induced platelet aggregation and thromboxane formation. In type III resistance (pseudo-resistance), platelet aggregation was induced by a low concentration of collagen (1 microg/ml) despite of a complete inhibition of thromboxane formation by oral aspirin treatment. This typology of aspirin resistance should help to clarify the mechanisms, the actual rate, and the possible clinical consequences of this phenomenon.     

Genomic Instability in Pituitary Adenomas

Pituitary adenomas most commonly are identified as small, incidental microadenomas. They however may progress to macroadenoma forming intra and later suprasellar tumors which in about 1/3 of cases invade surrounding structures at the time of diagnosis. Mechanism of pituitary tumorigenesis remains still elusive. Because the value of karyotyping is limited by the technical problems related to cytogenetic methods, we studied the spectrum of chromosomal imbalances associated with pituitary adenoma using comparative genomic hybridization (CGH). Copy number aberrations on all 22 autosomes were evaluated by CGH using advanced computer software. In total, fifteen patients were included in the study of 9 non-invasive, 4 invasive and two recurrent adenomas. The mean age of the patients were 48 years ranging from 36 to 68 years. Five tumors showed hormonal activity. The histogram of all 15 cases representing the DNA imbalances as an incidence curve along each chromosome showed losses particularly for chromosomes 1p, 2q, 4, 5, 6, 11q, 12q, 13q and 18q as well as overrepresentation on 9q, 16p, 17p, 19, 20q. Functioning adenomas carried more imbalances than non-functioning, specifically deletions on chromosome 4 and 18q as well as overrepresentations of chromosomes 17 and 19. Invasive adenomas carried more overrepresentations at 1p34 than non-invasive tumors. Recurrent adenomas harbored more alterations than primary tumors, particularly DNA gains. The primary data is accessible at our CGH online tumor database at http://amba.charite.de/cgh. Reviewing the existing literature on the genetics of pituitary adenoma and discussing our results in this context, we hope that our study will contribute to the knowledge of this neoplasm.     

滋养层细胞与原代白血病细胞共培养体系的建立及其意义

目的:建立一套体外培养前B急性淋巴细胞白血病(ALL)原代细胞的方法,并尝试进行难治性白血病克隆的鉴定。方法:采用来源于骨髓的基质细胞HS-5作为滋养层细胞与原代白血病细胞进行双相培养,并通过药敏和凋亡检测进行双相培养体系生物动力学评估。结果:双相滋养层培养体系能够耐受细胞毒药物的毒性;8例前B急淋白血病原代细胞标本在基质滋养层支持下离体72 h存活率20.4%~68.3%不等,与无滋养层支持或基质细胞上清液支持的标本相比存活率有显著性提高;其中1例标本的体外生长与有否滋养层支持无关,怀疑为难治性白血病克隆。结论:骨髓基质细胞来源的滋养层具有一定的体外支持白血病细胞存活的能力,但存在个体差异,与肿瘤细胞本身生物学特征有关;利用双相培养体系可以在体外早期初步鉴别出难治性白血病克隆并早期制定干预措施。     

Evaluation of Bactec Mycosis IC/F and Plus Aerobic/F Blood Culture Bottles for Detection of Candida in the Presence of Antifungal Agents

Clinical practice guidelines recommend performing follow-up cultures for patients with candidemia in order to determine the time when Candida is cleared from the bloodstream. Since this requires culturing blood samples from patients undergoing antifungal treatment, we evaluated two blood culture bottles (the Bactec Mycosis IC/F [MICF], specifically adapted to the growth of fungi, and the Bactec Plus Aerobic/F [PAF], containing resins to inactivate anti-infective agents) for their effectiveness in detecting Candida albicans and Candida glabrata when seeded in concentrations of 1 CFU/ml and 10 CFU/ml, respectively, together with human whole blood and various antifungal agents in therapeutic peak serum concentrations (C_max). Significant differences between the MICF and PAF vials for the detection of Candida spp. were found when inoculated with caspofungin (0/12 versus 8/12) (P < 0.001) or amphotericin B (3/12 versus 12/12) (P < 0.001). Inoculation of fluconazole or voriconazole did not influence the effectiveness of detection in the MICF and PAF bottles (P = 1.0). Neither the MICF nor the PAF bottles detected Candida spp. reliably when seeded together with anidulafungin (1/12 versus 1/12) (P = 1.0) or micafungin (0/12 versus 1/12) (P = 1.0). The times to positivity of both bottles were significantly prolonged when antifungal agents were added compared to those of controls without antimycotic drugs (P < 0.001). Overall, the results of this in vitro study indicate that the PAF bottles detected Candida spp. more reliably than the MICF bottles when supplemented with certain antifungal agents. Consequently, clinical studies should evaluate whether this holds true when blood cultures from patients undergoing antifungal treatment are performed.     

How to report the antinuclear antibodies (anti-cell antibodies) test on HEp-2 cells: guidelines from the ICAP initiative

Immunologic Research - Results of the anti-nuclear antibodies-indirect immunofluorescence assay (anti-cell antibodies test) on HEp-2 cell substrates should be communicated to clinicians in a...     

Role for the fibrinogen-binding proteins Coagulase and Efb in the Staphylococcus aureus–Candida interaction

Staphylococcus aureus and Candida species are increasingly coisolated from implant-associated polymicrobial infections creating an incremental health care problem. Synergistic effects between both genera seem to facilitate the formation of mixed S. aureus–Candida biofilms, which is thought to play a critical role in coinfections with these microorganisms. To identify and characterize S. aureus factors involved in the interaction with Candida species, we affinity-panned an S. aureus phage display library against Candida biofilms in the presence or absence of fibrinogen. Repeatedly isolated clones contained DNA fragments encoding portions of the S. aureus fibrinogen-binding proteins coagulase or Efb. The coagulase binds to prothrombin in a 1:1 ratio thereby inducing a conformational change and non-proteolytic activation of prothrombin, which in turn cleaves fibrinogen to fibrin. Efb has been known to inhibit opsonization. To study the role of coagulase and Efb in the S. aureus–Candida cross-kingdom interaction, we performed flow-cytometric phagocytosis assays. Preincubation with coagulase reduced the phagocytosis of Candida yeasts by granulocytes significantly and dose-dependently. By using confocal laser scanning microscopy, we demonstrated that the coagulase mediated the formation of fibrin surrounding the candidal cells. Furthermore, the addition of Efb significantly protected the yeasts against phagocytosis by granulocytes in a dose-dependent and saturable fashion. In conclusion, the inhibition of phagocytosis of Candida cells by coagulase and Efb via two distinct mechanisms suggests that S. aureus might be beneficial for Candida to persist as it helps Candida to circumvent the host immune system.     

Musculoskeletal extremity injuries in a cohort of schoolchildren aged 6–12: A 2.5‐year prospective study

The objectives of this prospective school cohort study were to describe the epidemiology of diagnosed musculoskeletal extremity injuries and to estimate the injury incidence rates in relation to different settings, different body regions and injury types. In all, 1259 schoolchildren, aged 6–12, were surveyed weekly during 2.5 years using a new method of automated mobile phone text messaging asking questions on the presence of any musculoskeletal problems. All injuries were clinically diagnosed. Physical activity was measured from text messaging and accelerometers. A total number of 1229 injuries were diagnosed; 180 injuries in the upper extremity and 1049 in the lower extremity, with an overall rate of 1.59 injuries per 1000 physical activity units [95% confidence interval (CI) 1.50–1.68]. Upper extremities accounted for a rate of 0.23 (95% CI 0.20–0.27) and lower extremities accounted for 1.36 (95% CI 1.27–1.44). This study has added a wide overall perspective to the area concerning incidence and incidence rates of musculoskeletal extremity injuries in schoolchildren aged 6–12 years, including severe and less severe, traumatic, and overuse injuries. The understanding of injury epidemiology in children is fundamental to the acknowledgement and insurance of the appropriate prevention and treatment.