Implant fixation in knee replacement: Preliminary in vitro comparison of ceramic and metal cemented femoral components

Improved wear resistance in total knee replacement (TKR) is a suitable goal. Whereas the use of metal components is well established, mechanical loosening in recently introduced ceramic components are a cause of concern. The scope of this work was to test in vitro whether ceramic TKR femoral components are more prone to mechanical loosening than metal ones. Composite femurs were implanted with commercially available TKR metal components, and with ceramic components having identical shape to the metal ones. Implanted femurs were tested on a knee simulator for up to 5 × 10^–6 cycles. Inducible micromotions and permanent migrations were recorded throughout the test. The cement layers were inspected for signs of damage or fracture. Micromotions and migrations were similar for metal and ceramic components: their magnitude and trend over time indicated that no implant was becoming loose. When there were statistically significant differences, the ceramic components were more stable than the metal ones. When the cement layers were inspected, a few short cracks were observed; most such cracks appeared during the first cycles, while no further damage occurred in the rest of the test. The type of damage found for both the metal and the ceramic components is compatible with well-fixed implants after long-term cycling. Altogether, no remarkable difference was found between the metal and ceramic components. Therefore, this study rejects the hypothesis that ceramic TKR femoral components are more prone to mechanical loosening. Although this study had a limited sample size, it provides novel pre-clinical indications about the potential of ceramic TKR femoral components.     

Resident alveolar macrophages are master regulators of arrested alveolarization in experimental bronchopulmonary dysplasia

Trophic functions for macrophages are emerging as key mediators of developmental processes, including bone, vessel, and mammary gland development. Yolk sac‐derived macrophages mature in the distal lung shortly after birth. Myeloid‐lineage macrophages are recruited to the lung and are activated under pathological conditions. These pathological conditions include bronchopulmonary dysplasia (BPD), a common complication of preterm birth characterized by stunted lung development, where the formation of alveoli is blocked. No study has addressed causal roles for immune cells in lung alveolarization. We employed antibody‐based and transgenic death receptor‐based depletion approaches to deplete or prevent lung recruitment of immune cell populations in a hyperoxia‐based mouse model of BPD. Neither neutrophils nor exudate macrophages (which might include lung interstitial macrophages) contributed to structural perturbations to the lung that were provoked by hyperoxia; however, cells of the Csf1r‐expressing monocyte/macrophage lineage were implicated as causal mediators of stunted lung development. We propose that resident alveolar macrophages differentiate into a population of CD45⁺ CD11c⁺ SiglecF⁺ CD11b⁺ CD68⁺ MHCII⁺ cells, which are activated by hyperoxia, and contribute to disturbances to the structural development of the immature lung. This is the first report that causally implicates immune cells in pathological disturbances to postnatal lung organogenesis. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Expression patterns in feline blood and tissues of α<Subscript>1</Subscript>-acid glycoprotein (AGP) and of an AGP-related protein (AGPrP)

₁-Acid glycoprotein (AGP) is an acute-phase protein (APP) that modulates immune responses, probably – at least in humans – owing to the modification of its glycosylation pattern. On this perspective, feline AGP can be a useful comparative model, as it has different concentrations in cats susceptible or resistant to some disease. As a preliminary approach to the study of feline AGP (fAGP) we have purified this protein from feline serum by HPLC using human AGP (hAGP) as a model. Immunoblotting with a polyclonal antibody against fAGP and with a monoclonal antibody against hAGP was performed on serum from healthy cats, from cats exposed to feline coronavirus (FCoV) infection and from cats with purulent inflammations, such as feline infectious peritonitis (FIP), feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV). Immunohistochemistry on tissues from healthy cats and from cats with different diseases (FIP, FIV, FeLV, locally extensive inflammation) was also performed with the same antibodies. Both hAGP and fAGP have been purified to homogenity as determined by SDS-PAGE. fAGP did not react with the anti-hAGP antibody which, in contrast, detected in feline serum a low MW protein that we called fAGP-related protein (fAGPrP). This protein was underexpressed in cats with FeLV and FIP. Both fAGP and fAGPrP were immunohistochemically detected in plasma and hepatocytes with a stronger intensity in cats with FIP and some inflammatory conditions. Moreover, fAGPrP was detected in the cytoplasm of tissue cells, most likely identifiable with plasma cells. These cells were rarely detectable in cats with FIV and FeLV, and numerous in cats with FIP and with locally extensive inflammation. In conclusion, purified fAGP has physicochemical characteristics similar to those of hAGP, but does not cross-react with anti-hAGP antibodies. In contrast, the anti-hAGP detected an AGP-related protein whose blood concentration and tissue distribution was not related to that of fAGP. Moreover, both fAGP and fAGPrP were differently expressed in cats with pathologic conditions compared to controls. Further study of these proteins by analysing their structural characteristics is required.Abbreviations AGP ₁-Acid glycoprotein - APP acutephase protein - FC0V feline coronavirus - FeLV feline leukemia virus - FIP feline infectious peritonitis - FIV feline immunodeficiency virus Originally presented at the ACCA meeting 2002, Sandwich, Kent, UK.     

Maternal uniparental disomy of chromosome 4 in a patient with limb-girdle muscular dystrophy 2E confirmed by SNP array technology

The limb-girdle muscular dystrophies (LGMDs) are a heterogenous group of diseases characterized by shoulder-girdle and pelvic muscle weakness and wasting. LGMD 2E is an autosomal recessively inherited form of the disease caused by mutations in the β-sarcoglycan (SGCB) gene located at 4q12. In this report, we describe a patient who demonstrates non-Mendelian inheritance of a homozygous missense mutation in SGCB resulting in disease expression. A combination of single-nucleotide polymorphism (SNP) array technology and microsatellite analysis revealed the occurrence of maternal uniparental disomy (UPD) for chromosome 4 in the patient. As a consequence of segmental isodisomy at 4q12, the patient inherited two identical SGCB alleles carrying a missense mutation predicted to result in abnormal protein function. SNP array technology proved to be an elegant means to determine the most probable mechanism of UPD formation in this case, and enabled us to determine the location of recombination events along chromosome 4. In our patient, UPD likely arose from a trisomy rescue event due to maternal meiotic non-disjunction that we speculate may have been caused by abnormal recombination at the pericentromeric region. Maternal UPD 4 is a rare finding, and to our knowledge this is the first reported case of UPD in association with LGMD.     

KSHV DNA viremia correlates with low CD4+ cell count in Italian males at the time of diagnosis of HIV infection

To evaluate the relevance and the virological and immunological markers of Kaposi sarcoma herpesvirus 8 (KSHV) viremia in Italian male patients at the time of diagnosis of infection with HIV‐1, 481 men infected with HIV were recruited consecutively. The presence of KSHV DNA was evaluated in peripheral blood mononuclear cells (PBMCs) and in plasma and correlated with demographic and viro‐immunological parameters. Seventy‐four patients had KSHV DNA detected in PBMCs. By univariate analysis, the presence of KSHV DNA was associated significantly with unprotected homosexual relationships (P = 0.003) and it was significantly higher in patients with CD4+ cell <350 (P = 0.025). By multivariate analysis, homosexual relationships were associated independently with KSHV DNA in PBMCs (OR: 3.25; 95% CI: 1.1–9.7; P = 0.035). Among the 74 patients with KSHV DNA detected in PBMCs, plasma samples from 60 were analyzed and 33 were positive for KSHV DNA. The CD4+ cell counts and percentages were significantly lower in patients with KSHV DNA in both PBMCs and plasma as compared to patients with only KSHV DNA in PBMCs (P = 0.006 and P = 0.019, respectively). Among the patients with KSHV DNA detected in PBMCs, all 13 patients with CD4+ cells count <200 had detectable levels of KSHV in their plasma. By multivariate analysis adjusted for the epidemiologic and virological parameters, low CD4+ cell count was the only independent variable associated with the presence of KSHV DNA in plasma (OR, 0.001; 95% CI: <0.001–0.001; P = 0.03). In HIV‐positive antiretroviral therapy‐naïve males, KSHV active replication as detected by KSHV DNA in plasma was associated significantly with low CD4+ cell count. J. Med. Virol. 83:384–390, 2011. © 2011 Wiley‐Liss, Inc.     

Microseparation and stripe wear in alumina-on-alumina hip implants

The combination of materials that still has highest wear resistance for total hip replacement is ceramic-on-ceramic. However, brittleness is a major concern for ceramics: in vivo and in vitro studies on ceramic hip prostheses correlate microseparation with hip noise, ceramic wear, or ceramic liner damage. Ceramic microseparation can lead to edge load, ceramic head wear, and squeaking. The aim of this in vitro study was to investigate whether different angles of inclination influence the wear pattern of alumina-on-alumina hip joints with micro-separation during the swing phase. We also evaluated the wear rate obtained from this in vitro investigation with retrieval specimens obtained at 13 years' mean follow-up. The study was performed using a 12-station hip joint wear simulator (Shore Western, Monrovia, CA, USA) under bovine calf serum used as lubricant. Wear was evaluated by the gravimetric method and the test length was set at two million cycles. After two million cycles, a volumetric loss of 0.11 ±0.03 mm3 and 0.12 ±0.06 mm3 was observed, respectively, for 23° and 63° angles of inclination. In particular, the results obtained in this work revealed an increase of about 12-fold compared to previous results without microseparation conditions. No significant differences were observed between the two different inclinations on the wear patterns of the acetabular cups with a level of significance of a = 0.5. The location and general shape of the stripes wear were similar for the retrieved and simulator balls.     

Citation classics in periodontology: a controlled study

AIM: The aims of this study were to identify the most cited articles in Periodontology published from January 1990 to March 2005; and to analyse the differences between citation Classics and less cited articles. MATERIAL AND METHODS: The search was carried out in four international periodontal journals: Journal of Periodontology, Journal of Clinical Periodontology, International Journal of Periodontics and Restorative Dentistry and Journal of Periodontal Research. The Classics, that are articles cited at least 100 times, were identified using the Science Citation Index database. From every issue of the journals that contained a Classic, another article was randomly selected and used as a Control. RESULTS: Fifty-five Classics and 55 Controls were identified. Classic articles were longer, used more images, had more authors, and contained more self-references than Controls. Moreover Classics had on the average a bigger sample size, often dealt with etiopathogenesis and prognosis, but were rarely controlled or randomized studies. CONCLUSIONS: Classic articles play an instructive role, but are often non-Controlled studies.     

Short- and long-term periodontal evaluation of impacted canines treated with a closed surgical-orthodontic approach

AIM: The aims were to evaluate and compare the periodontal status of unilateral impacted maxillary canines treated by a combined surgical-orthodontic technique with that of normally erupted controlateral canines. MATERIAL AND METHODS: One hundred and twenty-five patients, consecutively enrolled, aged between 12.8 and 52.0 years, 31 males and 94 females, presented one impacted maxillary canine (test group) and the controlateral canine normally erupted (control group). All cases were treated by a surgical flap and orthodontic traction directed to the centre of the crest and evaluated periodontally at the end of treatment. Fifty-eight patients were followed up for a mean of 3.4 +/- 0.5 years. Pocket depth (PD), keratinized tissue width (KT) and gingival recession were recorded. Multilevel models were created. RESULTS: At the end of the orthodontic treatment, PD and KT of the 125 impacted canines were slightly, but statistically significantly higher than controls. Only one treated canine showed a recession (1 mm). At follow-up (58 patients), this difference decreased and the two groups were not significantly different. CONCLUSIONS: The combined technique permitted the traction of the impacted canines to the centre of the crest, thus simulating a physiological eruption pattern. Correct alignment and good periodontal status were obtained.