Platelet interactions with calcium-phosphate-coated surfaces

Many studies have shown that calcium-phosphate (CaP)-coated endosseous implants exhibit more peri-implant bone formation and bone contact at early healing times than uncoated implants. Since the rate of healing is influenced by blood/implant interactions and possibly the degree of blood platelet activation, the aim of this study was to determine whether the topography, microtopography, or the presence of calcium (Ca) and phosphate (PO(4)) ions in the implant surface plays a predominant role in platelet activation. We define the threshold between topography and microtopography as the limit of the scale range of platelets themselves; thus, a microtopographic surface is defined by one which exhibits features 3mum. With the help of four international collaborating laboratories, we prepared 11 titanium and CaP-modified titanium surfaces each with different (micro)topographies and interrogated these surfaces with both platelet adhesion (lactate dehydrogenase activity) and platelet activation (microparticle formation and P-selectin expression) assays. Our results show that: calcium (Ca)- and phosphate (PO(4))-containing surfaces of increasing surface microtopographical complexity exhibit increasing platelet activation; surfaces with similar surface microtopographies show similar levels of platelet activation regardless of the presence of Ca and PO(4) in the surface; and that surface microtopography is responsible for platelet activation rather than the presence of Ca and PO(4) in the surface.     

The effect of immunotherapy on eosinophil accumulation and production of eosinophil chemotactic activity in the lung of subjects with asthma during natural pollen exposure

Two groups of birch pollen--allergic patients with seasonal rhinoconjunctivitis and asthma were followed during two consecutive birch-pollen seasons, one group, N = 10, during a season with high pollen load, and one group, N = 15, during a season of low pollen load. Half the patients were treated with immunotherapy (IT) for 3 and 4 years, respectively. The other half of the patients served as control group (non-IT). Bronchoalveolar lavage (BAL) was performed once before each season and once during the pollen season. Eosinophil (EOS) numbers in BAL were increased (p less than 0.01) during the season with high pollen load but not in the season with a low pollen load, and this increment was absent in the IT-treated group. Also, the EOS cationic protein levels were raised in the non-IT-treated group during the season with a high pollen load. The levels of EOS and neutrophil chemotactic activity were raised in BAL in both seasons in the non-IT-treated group compared with the IT-treated group (p less than 0.02, p less than 0.003, p less than 0.04, and p less than 0.005 in high- and low-load pollen season, respectively). Serum and BAL eosinophil chemotactic activity (ECA) were positively correlated (p less than 0.001). We conclude that there is an influx of active EOSs into the lung of pollen-allergic patients with asthma during a pollen season, which may be abrogated by IT. Furthermore, the generation of ECA appears to be an extremely sensitive marker of antigenic exposure, and the potent inhibition of the generation of ECA by IT may provide a clue as to the mechanism of this treatment.     

Failure of primary breast cancer neoangiogenesis to predict pattern of distant metastasis

In the present study, the primary tumor angiogenesis characteristics of 81 stage IV previously untreated breast cancers with synchronous metastasis to different distant sites (10 patients with soft tissue metastases, 31 with bone metastases, and 40 with visceral metastases) were analyzed. The primary intratumor microvessel density was assessed by immunohistochemical assay on paraffin-embedded primary tumor samples, using a monoclonal anti-CD34 antibody. The mean primary intratumor microvessel density (at 400× fields) was 78±39 (SD) microvessels per field. The microvessel density was not significantly related to the main clinical/pathological features of the tumor (age, cytohistological grade, DNA ploidy, diameter, and receptor status). The percentage of tumor cases with high primary intratumor microvessel density (cut-off median value of the series 73±39 microvessels/field) did not significantly differ in patients with bone, soft tissue, or visceral metastatic disease. Aanalysis of clinical outcome showed a significantly shorter time to progression and overall survival for patients with visceral metastases (P<0.001 and P<0.0002 by log-rank, respectively). Presence of visceral metastases was confirmed to be the only independent prognostic factor related to a worse TTP (hazard risk 2.15, 95% confidence interval 1.14–4.03, P<0.02) and overall survival (hazard risk 1.81, 95% confidence interval 0.98–3.35, P<0.06) by multivariate analysis. In conclusion, the assessment of neoangiogenesis of primary breast cancer by CD34 expression does not provide information predictive of different distant sites of metastasis. Received: 15 June 2001 / Accepted: 12 September 2001     

Ratio of shear to load ground-reaction force may underlie the directional tuning of the automatic postural response to rotation and translation

This study sought to identify the sensory signals that encode perturbation direction rapidly enough to shape the directional tuning of the automatic postural response. We compared reactions to 16 directions of pitch and roll rotation and 16 directions of linear translation in the horizontal plane in freely standing cats. Rotations and translations that displaced the center of mass in the same direction relative to the feet evoked similar patterns of muscle activity and active ground-reaction force, suggesting the presence of a single, robust postural strategy for stabilizing the center of mass in both rotation and translation. Therefore we postulated there should be a common sensory input that encodes the direction of the perturbation and leads to the directional tuning of the early electromyographic burst in the postural response. We compared the mechanical changes induced by rotations and translations prior to the active, postural response. The only consistent feature common to the full range of rotation and translation directions was the initial change in ground-reaction force angle. Other variables including joint angles, ground-reaction force magnitudes, center of pressure, and center of mass in space showed opposite or nonsignificant changes for rotation and translation. Change in force angle at the paw reflects the ratio of loading force to slip force, analogous to slips during finger grip tasks. We propose that cutaneous sensors in the foot soles detect change in ground-reaction force angle and provide the critical input underlying the directional tuning of the automatic postural response for balance.     

Gene profiling reveals increased expression of uteroglobin and other anti-inflammatory genes in glucocorticoid-treated nasal polyps

BACKGROUND: Treatment with local glucocorticoids (GCs) decreases symptoms and the size of nasal polyps. This might depend on the downregulation of proinflammatory genes, as well as the upregulation of anti-inflammatory genes. OBJECTIVE: We sought to identify GC-regulated anti-inflammatory genes in nasal polyps. METHODS: Affymetrix DNA microarrays were used to analyze the expression of 22,283 genes in 4 nasal polyps before and after local treatment with fluticasone (400 microg/d). Expression of uteroglobin and mammaglobin B was analyzed with real-time PCR in 6 nasal polyps and in nasal biopsy specimens from 6 healthy control subjects. RESULTS: Two hundred three genes had changed in expression in treated polyps, and 139 had known functions: 54 genes were downregulated, and 85 were upregulated. Genes associated with inflammation constituted the largest single functional group. These genes affected key steps in inflammation (eg, immunoglobulin production; antigen processing and presentation; and the chemoattraction and activation of granulocytes, T cells, and B cells). Several proinflammatory genes were downregulated. In contrast, some anti-inflammatory genes were upregulated. The gene that increased most in terms of expression was uteroglobin. This was confirmed with real-time PCR. By contrast, expression of uteroglobin was lower in untreated polyps than in healthy nasal mucosa. Immunohistochemical investigation showed staining of uteroglobin in the epithelium and in seromucous glands in control subjects and in nasal polyps. CONCLUSION: Upregulation of anti-inflammatory genes, such as uteroglobin, might contribute to the effects of local treatment with GCs in nasal polyps.     

Locating sequence on FPC maps and selecting a minimal tiling path

This study discusses three software tools, the first two aid in integrating sequence with an FPC physical map and the third automatically selects a minimal tiling path given genomic draft sequence and BAC end sequences. The first tool, FSD (FPC Simulated Digest), takes a sequenced clone and adds it back to the map based on a fingerprint generated by an in silico digest of the clone. This allows verification of sequenced clone positions and the integration of sequenced clones that were not originally part of the FPC map. The second tool, BSS (Blast Some Sequence), takes a query sequence and positions it on the map based on sequence associated with the clones in the map. BSS has multiple uses as follows: (1) When the query is a file of marker sequences, they can be added as electronic markers. (2) When the query is draft sequence, the results of BSS can be used to close gaps in a sequenced clone or the physical map. (3) When the query is a sequenced clone and the target is BAC end sequences, one may select the next clone for sequencing using both sequence comparison results and map location. (4) When the query is whole-genome draft sequence and the target is BAC end sequences, the results can be used to select many clones for a minimal tiling path at once. The third tool, pickMTP, automates the majority of this last usage of BSS. Results are presented using the rice FPC map, BAC end sequences, and whole-genome shotgun from Syngenta.     

Impact of highly active antiretroviral therapy on anemia and relationship between anemia and survival in a large cohort of HIV-infected women: Women's Interagency HIV Study

BACKGROUND: Anemia is common in HIV-infected individuals and may be associated with decreased survival. OBJECTIVE: To ascertain the impact of highly active antiretroviral therapy (HAART) on anemia and the relationship between anemia and overall survival in HIV-infected women. METHODS: A prospective multicenter study of HIV-1 infection in women. Visits occurred every 6 months, including a standardized history, physical examination, and comprehensive laboratory evaluation. The setting was a university-affiliated clinic at 6 sites in the United States. Participants were 2056 HIV-infected women from the Women's Interagency HIV Study (WIHS). The outcome measure was anemia, defined as hemoglobin (Hb) <12 g/dL. Survival analysis was based on overall mortality during the follow-up period. RESULTS: Among HIV-infected women who were not anemic at baseline, 47% became anemic by 3.5 years of follow-up. On multivariate analysis, the use of HAART was associated with resolution of anemia even when used for only 6 months (odds ratio [OR] = 1.45; P < 0.05). In the multivariate model, a CD4 cell count <200 cells/microL (OR = 0.56; P < 0.001); HIV-1 RNA level > or =50,000 copies/mL (OR = 0.65; P < 0.001), and mean corpuscular volume (MCV) value <80 fL (OR = 0.40; P < 0.001) were also associated with an inability to correct anemia. Similarly, use of HAART for 12 months or more was associated with a protective effect against development of anemia (OR = 0.71; P < 0.001). Among HIV-infected women, anemia was independently associated with decreased survival (hazard ratio [HR] = 2.58; P < 0.001). Other factors associated with decreased survival included a CD4 cell count <200 cells/microL (HR = 5.83; P < 0.001), HIV-1 RNA level > or = 50,000 copies/mL (HR = 2.12; P < 0.001), and clinical diagnosis of AIDS (HR = 2.83; P < 0.001). CONCLUSIONS: Anemia is an independent risk factor for decreased survival among HIV-infected women. HAART therapy for as little as 6 months is associated with resolution of anemia.     

Nucleation of calcium phosphate by surface-bound extracellular matrix

The native extracellular matrix (ECM) laid down on silicon and titanium surfaces by osteoblast-like SAOS-2 cells was exposed by selective removal of cells. This type of material surface ECM-Si, ECM-Ti was shown to promote the nucleation of calcium phosphate from a simulated body fluid (SBF). Microscopic and spectroscopic results revealed the effect was associated with a collagen fiber-free extracellular matrix.     

Kinetic studies of neutrophil phagocytosis: V. Studies on the co-operation between the Fc and C3b receptors

The co-operation between the Fc and C3b receptors of PMNs (neutrophil granulocytes) during phagocytosis has been studied by the effect of interference with either of the receptors. The significance of the Fc receptor for the mediation of internalization proposed by previous investigators was confirmed by the inhibition of both Fc- and C3b-mediated phagocytosis by Fc fragments of IgG and by Fab fragments of antiserum against the Fc part of IgG. C3b-receptor-mediated phagocytosis was inhibited by trypsin, granulocyte elastase, myeloperoxidase and H₂O₂. High concentrations of elastase and the combined action of H₂O₂ and myeloperoxidase generated a C3b-receptor dysfunction, which implied that the destruction of C3b-receptor function also disturbed Fc-receptor function. The demonstrated C3b receptor dysfunction indicated that the Fc and C3b receptors were closely situated in the cellular membrane of the PMN. A hypothesis for co-operation between the two receptor types would be that the C3b receptor initially facilitates the adherence of an IgG-C3b-coated particle. Secondly, the C3b receptor would facilitate the IgG-Fc-receptor contact either by some kind of structural derangement to permit the entrance of the IgG-C3b complex or by removal of C3b from the Fc part of IgG.