Calcium signaling in platelets

Agonist-induced elevation in cytosolic Ca2+ concentrations is essential for platelet activation in hemostasis and thrombosis. It occurs through Ca2+ release from intracellular stores and Ca2+ entry through the plasma membrane (PM). Ca2+ store release is a well-established process involving phospholipase (PL)C-mediated production of inositol-1,4,5-trisphosphate (IP3), which in turn releases Ca2+ from the intracellular stores through IP3 receptor channels. In contrast, the mechanisms controlling Ca2+ entry and the significance of this process for platelet activation have been elucidated only very recently. In platelets, as in other non-excitable cells, the major way of Ca2+ entry involves the agonist-induced release of cytosolic sequestered Ca2+ followed by Ca2+ influx through the PM, a process referred to as store-operated calcium entry (SOCE). It is now clear that stromal interaction molecule 1 (STIM1), a Ca2+ sensor molecule in intracellular stores, and the four transmembrane channel protein Orai1 are the key players in platelet SOCE. The other major Ca2+ entry mechanism is mediated by the direct receptor-operated calcium (ROC) channel, P2X1. Besides these, canonical transient receptor potential channel (TRPC) 6 mediates Ca2+ entry through the PM. This review summarizes the current knowledge of platelet Ca2+ homeostasis with a focus on the newly identified Ca2+ entry mechanisms.

Individual addressing of trapped ions and coupling of motional and spin states using RF radiation

Individual electrodynamically trapped and laser cooled ions are addressed in frequency space using radio-frequency radiation in the presence of a static magnetic field gradient. In addition, an interaction between motional and spin states induced by an rf field is demonstrated employing rf optical double resonance spectroscopy. These are two essential experimental steps towards realizing a novel concept for implementing quantum simulations and quantum computing with trapped ions.

[No influence of physiotherapy on outcome after open repair of achilles tendon ruptures?]

AIM

Many studies have been performed to analyse the influence of surgical techniques and the postoperative aftercare after Achilles tendon ruptures on the outcome. However, there is no study investigating the influence of physiotherapy on outcome after surgical repair and standardised early functional rehabilitation of Achilles tendon rupture, so that this was the objective of the present study.

PATIENTS AND METHODS

In this retrospective study, 104 patients with Achilles tendon ruptures, all treated by open repair followed by a standardised early rehabilitation, were evaluated by the Thermann score. The average age was 42 years. We could identify 3 patient groups. Group I (n=23) did not receive any physiotherapy. Group II (n=41) received physiotherapy for 3-6 weeks, and group III (n=40) received more than 6 weeks of physiotherapy. Physiotherapy consisted of 3 units per week. Each unit lasted for 30 min. All groups were compared statistically via variance analysis.

RESULTS

Group I scored on average 88.8 points, group II 88.6 and group III 87.0 points. There were no statistically significant differences between the three groups (p=0.50). The age of patients had also no relevant influence on the outcome (p=0.48).

CONCLUSIONS

Physiotherapy and age of the patients involved were not found to influence the outcome after open augmented repair of Achilles tendon ruptures followed by a standardised early rehabilitation. These results should be confirmed by a prospective randomised trial. Also elderly patients participating in demanding sport activities should receive a surgical repair.

Children with absent surfactant protein D in bronchoalveolar lavage have more frequently pneumonia

Surfactant protein D (SP-D) is an important component of the pulmonary host defense system. We hypothesized that bronchoalveolar lavage (BAL) SP-D levels are lower in children presenting with recurrent bronchitis, providing evidence for a role of SP-D in human respiratory diseases. SP-D levels in BAL were measured in 45 children, who suffered from recurrent bronchitis for an average of 2-3 yr. Clinical outcome was assessed 2 yr after BAL. For comparison, BAL fluids from 15 control children without respiratory symptoms were evaluated. Among the 45 children with recurrent bronchitis, 12 had no SP-D in their BAL at the time of investigation. These SP-D-deficient patients had more frequently pneumonias and their long-term outcome was worse than that of the children with detectable SP-D. No genetic cause could be identified for the SP-D deficiency. Among the children with recurrent bronchitis and SP-D clearly detectable in BAL, those with the diagnosis of allergic asthma had threefold elevated levels compared with controls. In accordance with animal and in vitro data, elevated SP-D concentrations in BAL may represent an up-regulation due to allergic airway inflammation. In contrast, SP-D deficiency due to consumption or failure to up-regulate SP-D may be linked to pulmonary morbidity in children.

Improved mouse models of allergy and allergic asthma--chances beyond ovalbumin

Allergic asthma is defined as a hypersensitivity reaction of the lung towards per se harmless antigens, e.g. pollen and house dust mite, accompanied with a chronic eosinophilic inflammation of the lung. During the course of the disease, physiological and structural changes in the lung occur, i.e. airway hyperresponsiveness, restricted airflow and airway remodelling. In addition to ovalbumin-induced mouse models of acute asthma, recently new models were developed, which show a closer resemblance to human asthma, both regarding the induction of characteristics of chronic allergic inflammation and the use of clinical relevant allergens. Moreover, attention is paid on the influence of adjuvants or the route of sensitisation on the protocol outcomes. The effort spent in development of these new models will be worthwhile, especially for research in the field of immuno-therapy. These improved animal models may broaden the knowledge of the disease and thereby provide new strategies for preventive and therapeutic interventions.

Flexible, intensive insulin therapy and dietary freedom in adolescents and young adults with Type 1 diabetes: a prospective implementation study

AIMS

To assess the outcome of a Diabetes Treatment and Teaching Programme (DTTP) on glycated haemoglobin (HbA1c), severe hypoglycaemia (SH) and severe ketoacidosis (SKA) in adolescents and young adults with Type 1 diabetes.

METHODS

Quality-assurance project with assessment of participants 1 year after participation in a DTTP (5-day inpatient course, groups < or = 10 patients, fixed curriculum of education/training, introduction of dietary freedom). Before-after analyses of participants aged 12-15, 15-18, 18-21 and 21-24 years. Main outcome measures were HbA1c, SH and SKA.

RESULTS

For the 1592 participants, aged 12 to 24 years, mean age at enrolment was 19 +/- 3 years, mean duration of diabetes was 7.3 +/- 5.4 (range 0.3-24) years, mean baseline HbA1c declined from 8.8 +/- 2.3% to 8.1 +/- 2.0%. The incidence of SH was 0.31 vs. 0.11 events/patient/year; the incidence of SKA 0.17 vs. 0.07 events/patient/year. In mixed effects models taking into account effects of centres, age and diabetes duration, the mean difference was -0.64%[P < 0.001, 95% confidence interval (CI) -0.79 to -0.5] for HbA1c, -0.2 events/patient/year (P < 0.0001, 95% CI -0.28 to -0.12) for SH and -0.1 events/patient/year (P < 0.0001, 95% CI -0.14 to -0.06) for SKA.

CONCLUSIONS

Adolescents and young adults with Type 1 diabetes benefit from participation in a standard DTTP for flexible, intensive insulin therapy and dietary freedom.

Ex vivo testing of immune responses in precision-cut lung slices

The aim of this study was the establishment of precision-cut lung slices (PCLS) as a suitable ex vivo alternative approach to animal experiments for investigation of immunomodulatory effects. For this purpose we characterized the changes of cytokine production and the expression of cell surface markers after incubation of PCLS with immunoactive substances lipopolysaccharide (LPS), macrophage-activating lipopeptide-2 (MALP-2), interferon gamma (IFNgamma), and dexamethasone. Viability of PCLS from wild-type and CD11c-enhanced yellow fluorescent protein (CD11-EYFP)-transgenic mice was controlled by measurement of lactate dehydrogenase (LDH) enzyme activity and live/dead fluorescence staining using confocal microscopy. Cytokines and chemokines were detected with Luminex technology and ELISA. Antigen presenting cell (APC) markers were investigated in living mouse PCLS in situ using confocal microscopy. LPS triggered profound pro-inflammatory effects in PCLS. Dexamethasone prevented LPS-induced production of cytokines/chemokines such as interleukin (IL)-5, IL-1alpha, TNFalpha, IL-12(p40), and RANTES in PCLS. Surface expression of MHC class II, CD40, and CD11c, but not CD86 was present in APCs of naive PCLS. Incubation with LPS enhanced specifically the expression of MHC class II on diverse cells. MALP-2 only failed to alter cytokine or chemokine levels, but was highly effective in combination with IFNgamma resulting in increased levels of TNFalpha, IL-12(p40), RANTES, and IL-1alpha. PCLS showed characteristic responses to typical pro-inflammatory stimuli and may thus provide a suitable ex vivo technique to predict the immunomodulatory potency of inhaled substances.

Encoding, rehearsal, and recall in signers and speakers: shared network but differential engagement

Short-term memory (STM), or the ability to hold verbal information in mind for a few seconds, is known to rely on the integrity of a frontoparietal network of areas. Here, we used functional magnetic resonance imaging to ask whether a similar network is engaged when verbal information is conveyed through a visuospatial language, American Sign Language, rather than speech. Deaf native signers and hearing native English speakers performed a verbal recall task, where they had to first encode a list of letters in memory, maintain it for a few seconds, and finally recall it in the order presented. The frontoparietal network described to mediate STM in speakers was also observed in signers, with its recruitment appearing independent of the modality of the language. This finding supports the view that signed and spoken STM rely on similar mechanisms. However, deaf signers and hearing speakers differentially engaged key structures of the frontoparietal network as the stages of STM unfold. In particular, deaf signers relied to a greater extent than hearing speakers on passive memory storage areas during encoding and maintenance, but on executive process areas during recall. This work opens new avenues for understanding similarities and differences in STM performance in signers and speakers.

Toward distinguishing woodsmoke and diesel exhaust in ambient particulate matter

Particulate matter (PM) from biomass burning and diesel exhaust has distinct X-ray spectroscopic, carbon specific signatures, which can be employed for source apportionment. Characterization of the functional groups of a wide selection of PM samples (woodsmoke, diesel soot, urban air PM) was carried out using the soft X-ray spectroscopy capabilities at the synchrotron radiation sources in Berkeley (ALS) and Brookhaven (NSLS). The spectra reveal that diesel exhaust particulate (DEP) matter is made up from a semigraphitic solid core and soluble organic matter, predominantly with carboxylic functional groups. Woodsmoke PM has no or a less prevalent, graphitic signature, instead it contains carbon-hydroxyl groups. Using these features to apportion the carbonaceous PM in ambient samples we estimate that the relative contribution of DEP to ambient PM in an urban area such as Lexington, KY and St. Louis, MO is 7% and 13.5%, respectively. These values are comparable to dispersion modeling data from nonurban and urban areas in California, and with elemental carbon measurements in urban locations such as Boston, MA, Rochester, NY, and Washington, DC.

Bicontact Plasmacup THA in patients with staged bilateral hip replacement

AIM

In a retrospective study, all patients with bilateral cementless Bicontact-Plasmacup total hip arthroplasty in the period May 1993 to June 2000 were followed up clinically and radiologically.

METHOD

Out of 537 hip replacements performed in this period with this combination of implants, 46 patients had bilateral surgery. At follow-up, the Harris Hip Score, the radiological changes between primary implantation and most recent follow-up and the radiologically visible wear of the polyethylene cup component were studied.

RESULTS

Thirty-seven patients were followed up. One patient had died and 8 patients could not be contacted. The average age at the first hip replacement was 57.8 years and it was 59.1 years at the second operation. The follow-up period was 6.5 years (min 4.8 and max 9.8 years). The average Harris Hip Score at the time of follow-up was 91 points. Up to the time of follow-up, no stem or cup implant had to be revised. There were no radiological signs of stem loosening. In the case of the cup components, increased linear wear values of more than 0.15 mm/year were found in 4 THAs that used a 28-mm ceramic-polyethylene bearing. In two of these cases, the cup was in a markedly steep position. One of these cup components was assessed as loosened.

CONCLUSION

The results of this study have confirmed the biomechanical concept of the implant system employed. In contrast to the stem design, the cup design and slide bearing options have been supplemented in the meantime. The ceramic bearing was only available from 1997 and was used less often in this group of patients than would be indicated today for patients of the same age and degree of activity.

Neurotrophic factors--a tool for therapeutic strategies in neurological, neuropsychiatric and neuroimmunological diseases?

Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) belong to the protein family of neurotrophins. They both display profound neuromodulatory functions and are essentially involved in the survival and homeostatic maintenance of central and peripheral neurons during development and adulthood. Moreover, NGF and BDNF are known to modulate immune cell function and thus serve as mediators in the reciprocal cross talk between neurons and immune cells. Neurotrophic factors have been implicated in pathophysiological mechanisms of many diseases of the nervous and the immune system, such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), neuropathy, pain, allergic bronchial asthma (BA) and neurotrophic keratitis. For all these diseases research has reached the point of creating strategies for therapeutic intervention with neurotrophins. In this review, we present an overview of the pathophysiology, therapeutic interventions and strategies concerning NGF and BDNF in the mentioned diseases.

Anti-chromatin and anti-C1q antibodies in systemic lupus erythematosus compared to other systemic autoimmune diseases

OBJECTIVE

To evaluate the prevalence, sensitivity, and specificity of anti-chromatin and anti-C1q antibodies in systemic lupus erythematosus (SLE) and lupus nephritis compared to small vessel vasculitis and other connective tissue diseases. To provide long-term follow-up data for anti-chromatin antibodies in lupus nephritis.

METHODS

We determined the significance of anti-nuclear antibodies (ANA), anti- double-stranded DNA (anti-dsDNA), anti-chromatin, and anti-C1q antibodies, as well as complement factors C3 and C4, in relation to disease activity in SLE patients with (n = 47; long-term follow-up data for 33 patients) and without (n = 31) biopsy-confirmed lupus nephritis, microscopic polyangiitis (n = 37), Wegener's granulomatosis (n = 66), primary Sjögren's syndrome (n = 17), limited scleroderma (CREST syndrome) (n = 6), and progressive systemic scleroderma (PSS) (n = 11).

RESULTS

Anti-chromatin antibodies were more specific and sensitive than anti-C1q antibodies in distinguishing SLE patients from those with other systemic autoimmune diseases [anti-chromatin: sensitivity 64.1%, specificity 99.2%, odds ratio (OR) 219.6; anti-C1q: sensitivity 50%, specificity 72.6%, OR 2.65]. Anti-C1q antibodies were present in 75% of patients with Sjögren's syndrome and 35.1% of patients with microscopic polyangiitis. Anti-chromatin antibodies could identify SLE in patients with positive ANA but negative anti-dsDNA antibodies. Persisting anti-chromatin antibodies indicated SLE disease activity, even if anti-dsDNA antibodies had become negative. In long-term follow-up, those SLE patients with negative anti-dsDNA antibodies but persisting ANA and anti-chromatin antibodies relapsed if immunosuppression had been tapered. Anti-chromatin antibodies correlated with the SLE disease activity index (SLEDAI) as a marker of disease activity.

CONCLUSIONS

The measurement of anti-chromatin, but not anti-C1q, antibodies in patients with systemic autoimmune diseases increases diagnostic sensitivity and specificity for SLE and assists in treatment decisions in anti-dsDNA-negative patients.

Beta-globin gene cluster polymorphisms are strongly associated with severity of HbE/beta(0)-thalassemia

We evaluated the contribution of 67 single nucleotide polymorphisms (SNPs) within the beta-globin gene cluster to disease severity in groups of 207 mild- and 305 severe unrelated patients from Thailand with Hemoglobin E (HbE)/beta(0)-thalassemia and normal alpha-globin genes. Our analysis showed that these SNPs comprise two distinct linkage disequilibrium blocks, one containing the beta-globin gene and the other extending from the locus control region (LCR) to the delta gene, which are separated by a recombination hotspot in the narrow region of the beta-globin gene promoter. Forty-five SNPs within the interval including the LCR region and the delta gene showed strong association with disease severity. The strongest association was observed with the XmnI polymorphism located 158-bp upstream to the G gamma gene (p = 4.6E-12). Carriers of the T allele of XmnI were more likely to have a milder disease course and higher level of fetal hemoglobin (HbF) in both the mild (p = 0.005) and severe (p = 8.7E-06) patient groups. Haplotype analysis revealed that the T allele of XmnI was nearly always in cis with the HbE allele. The high frequency of this haplotype may be favored by positive selection against malarial infection. Further studies are needed to validate this hypothesis and determine whether XmnI or another closely linked variant modulates severity and HbF levels in patients with beta(0)-thalassemia/HbE disease.

Penetration depth of a dye marker into dentine using a novel hydrodynamic system (RinsEndo�)

AIM

To investigate the efficiency of a hydrodynamic irrigation system compared with conventional cleansing techniques in root canals.

METHODOLOGY

Forty-five freshly extracted single-rooted teeth were de-coronated and their root canals were enlarged to size 30 at the apex. The teeth were randomly divided into three groups (n = 15) for the final rinsing sequence using 2% NaOCl plus acid fuchsin: group I: static application of irrigant, 3 min; group II: flushing with a syringe; 5-mL NaOCl, 1 min; group III: RinsEndo-system; 5-mL NaOCl, 50 s. Apical extrusion was documented photographically. The roots were sectioned at 2, 4, 6 and 8 mm from their apices and the penetration depths of dye into dentine measured, using a stereomicroscope. Wilcoxon's test and Pearson's chi-squared test were employed to prove statistic relevance.

RESULTS

Greater dye penetration depth into the dentinal tubules was achieved when employing hydrodynamic rinsing procedures. Using this technique, 23% of the specimens were penetrated for more than 50% of their dentine thickness, whereas the results for flushing with a syringe were 12% (static application, 7%). No penetration of dentine occurred in 63% of specimens with static application, 39% flushing with a syringe and 15% using the hydrodynamic system (P < 0.05 Pearson's chi-squared test). Apical extrusion occurred more frequently after hydrodynamic rinsing (extruded specimens: RinsEndo = 80%; static application/flushing with a syringe = 13%; P < 0.05 Pearson's chi-squared test).

CONCLUSIONS

Hydrodynamic rinsing demonstrated an improvement over conventional methods in terms of dentine penetration of a dye marker. A higher risk of apical extrusion with the RinsEndo-system was evident.