The effect of surface chemistry modification of titanium alloy on signalling pathways in human osteoblasts

Establishing and maintaining mature bone at the bone–device interface is critical to the long-term success of prosthesis. Poor cell adhesion to orthopaedic and dental implants results in implant failure. Considerable effort has been devoted to alter the surface characteristics of these biomaterials in order to improve the initial interlocking of the device and skeleton. We investigated the effect of surface chemistry modification of titanium alloy (Ti–6Al–4V) with zinc, magnesium or alkoxide-derived hydroxy carbonate apatite (CHAP) on the regulation of key intracellular signalling proteins in human bone-derived cells (HBDC) cultured on these modified Ti–6Al–4V surfaces. Western blotting demonstrated that modifying Ti–6Al–4V with CHAP or Mg results in modulation of key intracellular signalling proteins. We showed an enhanced activation of Shc, a common point of integration between integrins and the Ras/Mapkinase pathway. Mapkinase pathway was also upregulated, suggesting its role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the Mg and CHAP modified Ti–6Al–4V. Thus surface modification with CHAP or Mg may contribute to successful osteoblast function and differentiation at the skeletal tissue–device interface.     

Sutureless re-anastomosis by laparoscopy versus microsurgical re-anastomosis by laparotomy for sterilization reversal: a matched cohort study

BACKGROUND: Sutureless re-anastomosis per laparoscopy is an alternative for microsurgical re-anastomosis by laparotomy in the treatment of sterilized women with renewed child wish. Our aim was to compare pregnancy rates after both surgical techniques. METHODS: We performed a retrospective cohort study in which consecutive women who underwent sutureless re-anastomosis per laparoscopy were compared to women who underwent microsurgical re-anastomosis by laparotomy. Both procedures were performed in neighbouring hospitals in Northern-Brabant, The Netherlands, and women were matched for age. The primary outcome was time to ongoing pregnancy. RESULTS: Overall, we included 41 women who had sutureless re-anastomosis by laparoscopy, and 41 age-matched women who underwent microsurgical re-anastomosis by laparotomy. The number of women who conceived was 20 (15 ongoing pregnancies) in the sutureless laparoscopic group versus 26 (24 ongoing pregnancies) in the laparotomic group, a difference due to a longer follow-up period in the laparotomic group. Time to ongoing pregnancy was comparable in both groups (P=0.46), with 3 year cumulative ongoing pregnancy rates of 45 and 52% respectively. After adjustment for other prognostic factors, the fecundity rate ratio was 0.97 (95% CI 0.26-3.6), indicating a similar performance of the two techniques. CONCLUSION: The simplified stitchless laparoscopic procedure for reversal of tubal sterilization with the use of a tubal splint, clip fixation of the muscularis and fibrin glue resulted in a promising pregnancy rate, which was similar to the pregnancy rate obtained with the microsurgical re-anastomosis per laparotomy.     

A deficiency in Drak2 results in a T cell hypersensitivity and an unexpected resistance to autoimmunity

DRAK2 is a member of the death-associated protein (DAP)-like family of serine/threonine kinases. Members of this family induce apoptosis in various cell types. DRAK2, in particular, is specifically expressed in T cells and B cells, and it is differentially regulated during T cell development. To determine whether DRAK2 regulates lymphocyte apoptosis, we produced Drak2(-/-) mice. Contrary to our expectations, Drak2(-/-) T cells did not demonstrate any defects in apoptosis or negative selection; however, T cells from Drak2(-/-) mice exhibited enhanced sensitivity to T cell receptor-mediated stimulation with a reduced requirement for costimulation. These results provide evidence that DRAK2 raises the threshold for T cell activation by negatively regulating signals through the TCR. In contrast to other models of T cell hypersensitivity, Drak2(-/-) mice were remarkably resistant to experimental autoimmune encephalomyelitis (EAE). These results expose a new pathway regulating T cell activation and highlight the intricacies of induced autoimmune disease.     

Human eosinophils express and release IL-13 following CD28-dependent activation

Human eosinophils produce a large number of cytokines, including immunoregulatory cytokines. Given that eosinophils store and release interleukin (IL)-4, a key cytokine in the pathogenesis of allergic inflammation, and that IL-4 and IL-13 share common biological functions, we investigated the possibility that IL-13 may be synthesized by these cells. Using flow cytometry and immunocytochemistry, we show that eosinophils synthesize and store IL-13. Granule localization was demonstrated after subcellular fractionation, and IL-13 immunoreactivity was localized to crystalloid, granule-enriched fractions. Furthermore, electron microscopic analyses specifically localized IL-13 to the dense cores of bicompartmental secondary granules. Upon CD28 ligation, IL-13 was released by eosinophils, whereas a combination of CD28 and immunoglobulin A complexes resulted in decreased IL-13 secretion. Furthermore, eosinophil-derived IL-13 exerts a biological effect, inducing CD23 expression on B cells. By having the capacity to synthesize and release IL-13, eosinophils may participate in the development and maintenance of the T helper cell type 2 response, a prominent feature of allergic diseases.     

Reticulocyte counts before and after exercise: Trained vs. sedentary

Summary Reticulocyte count comparisons were made on ten trained and ten sedentary college males before and immediately after heavy exercise and following 15 min of recovery. No significant differences occurred within or between groups; in fact, all means were within the normal range. Previous findings were discussed. It was concluded that a physiologically significant increase in reticulocytes does not occur as a result of exercise or training and therefore can not be a mechanism for increased maximal oxygen uptake.     

Haplotype analysis of the BRCA2 9254delATCAT recurrent mutation in breast/ovarian cancer families from Spain

A frame-shift 9254del5 mutation was independently identified in 12 families, eleven of them with Spanish ancestors, in a BRCA2 screening performed in 841 breast and/or ovarian cancer families and in 339 women with breast cancer diagnosed before the age of 40 at different centers in France and Spain. We sought to analyze in detail the haplotype and founder effects of the 9254del5 and to estimate the time of origin of the mutation. Eight polymorphic microsatellite markers and two BRCA2 polymorphisms were used for the haplotype analyses. The markers were located flanking the BRCA2 gene spanning a region of 6.1 cM. Our results suggest that these families shared a common ancestry with BRCA2 9254del5, which is a founder mutation originating in the Northeast Spanish, with an estimated age of 92 (95% CI 56-141) generations.     

Determining optimal two-beam axial orientations for heart sparing in left-sided breast cancer patients

BACKGROUND AND PURPOSE: The optimal intensity fluence profile of a beam depends on the profiles of other beams but most optimizations assume fixed beam orientations, a priori. Breast cancer radiotherapy attempts to cover the target and to spare critical structures such as the heart and lungs. The study aims are (1) to determine and document the optimal two-beam orientation that best spares the heart for left-sided breast cancer patients and (2) to investigate the influence of the treatment technique (i.e., conformal versus intensity modulation) on the optimal objective cost function. MATERIAL AND METHODS: Ten left-sided breast cancer patients were planned using a conformal (3DCRT) and a simplified intensity modulated (sIMRT) technique using predefined segments and different two-beam orientations. Optimal segment weights were determined exhaustively for all axial two-beam combinations, in 5 degree increments, by minimizing a quadratic objective cost function. The resulting objective cost function was analyzed with respect to target geometry and treatment technique. RESULTS: The sIMRT plans are generally less sensitive to beam orientation compared to 3DCRT plans. Optimal two-beam orientations for 3DCRT and sIMRT plans exist and they correspond to a hinge angle of approximately 188 degrees and 160 degrees or 210 degrees (the latter is bimodal), respectively. CONCLUSIONS: The optimization software is a useful tool that can test many different beam combinations and estimate their associated objective cost values. Afterwards, the most promising beam orientations could be re-optimized under the TPS to fine-tune and verify the dose distributions. Optimal uniform two-beam orientations for the breast consist of opposing tangential medial and lateral beams. Optimal nonuniform two-beam orientations for left-sided breast cancers are bimodal, containing hinge angles around 160 degrees and 210 degrees. Nonuniform beam techniques are less sensitive to beam orientation compared to uniform beam techniques and result in significantly improved heart sparing but at a cost of slightly compromised planning target volume coverage.     

Properties of a Hemolysin Produced by Group B Streptococci

A hemolysin that appears to be responsible for the zones of beta-hemolysis surrounding colonies of group B streptococci (Streptococcus agalactiae) on blood agar plates has been isolated and partially purified. No soluble hemolysin was detectable in the supernatants of streptococcal cultures grown in several types of media. However, hemolytic activity was detected when streptococci were incubated with erythrocytes, and soluble hemolysin was isolated when bacterial suspensions were incubated in the presence of a variety of agents, including calf serum, albumin, Tween 80, and starch. Glucose and other fermentable carbohydrates stimulated hemolysin production, and metabolic inhibitors greatly reduced the titer of hemolysin that could be recovered, suggesting that cellular metabolism is necessary for hemolysin production or release. The soluble hemolysin was concentrated by ammonium sulfate precipitation and partially purified by gel filtration. Agents known to inhibit other streptococcal hemolysins, including phospholipids, trypan blue, proteases, and cholesterol, were tested for their effect on the group B hemolysin. Only the phospholipids inhibited hemolysin activity. The group B streptococcal hemolysin appears to be similar to, but distinct from, streptolysin S produced by Streptococcus pyogenes.     

Ellis‐van Creveld syndrome in a patient from Tanzania

We report an African infant with Ellis‐van Creveld (EVC) syndrome. EVC syndrome is a chondral and ectodermal dysplasia with autosomal recessive transmission. The baby presented with polydactyly, short limbs and atrioventricular septal defect, but was withdrawn from clinical follow up for the first year of life. Initial hematological abnormalities could not be explained and normalized later. EVC syndrome was confirmed by genetic analysis that showed two pathogenic mutations in the EVC2 gene, c.653_654del, p.Val218Glyfs*12 in exon 5, and c.2710C>T, p.Gln904* in exon 16. The variant c.653_654del; p.Val218Glyfs*12 in exon 5 has not been described before. Our review of medical literature suggested this is the first molecularly confirmed case of EVC syndrome in sub‐Saharan Africa.     

Mitochondrial DNA Heterogeneity in Tunisian Berbers

Berbers live in groups scattered across North Africa whose origins and genetic relationships with their neighbours are not well established. The first hypervariable segment of the mitochondrial DNA (mtDNA) control region was sequenced in a total of 155 individuals from three Tunisian Berber groups and compared to other North Africans. The mtDNA lineages found belong to a common set of mtDNA haplogroups already described in North Africa. Besides the autochthonous North African U6 haplogroup, a group of L3 lineages characterized by the transition at position 16041 seems to be restricted to North Africans, suggesting that an expansion of this group of lineages took place around 10500 years ago in North Africa, and spread to neighbouring populations. Principal components and the coordinate analyses show that some Berber groups (the Tuareg, the Mozabite, and the Chenini‐Douiret) are outliers within the North African genetic landscape. This outlier position is consistent with an isolation process followed by genetic drift in haplotype frequencies, and with the high heterogeneity displayed by Berbers compared to Arab samples as shown in the AMOVA. Despite this Berber heterogeneity, no significant differences were found between Berber and Arab samples, suggesting that the Arabization was mainly a cultural process rather than a demographic replacement.