Protective and Risk Factors for Humerus Head Necrosis After Proximal Humerus Fracture Treated with Internal Locking Plate

BackgroundProximal humerus fractures (PHF) are common and lead to post-traumatic humerus head necrosis (HHN) in 3–35% after ORIF with an internal locking plate. Few studies focus on this condition and risk factors remain a discussion topic. Hertel’s criteria for initial head ischemia right after fracture (fracture complexity, medial hinge displacement and short metaphyseal head extension) have recently been correlated to HHN, but there is still a clear lack of evidence on the topic. Due to its anatomical similarities to the proximal femur, some authors argue that PHF may as well benefit from early surgery to avoid head necrosis.MethodsIn this 10-year retrospective study, we assessed 305 patients from a single center. All cases were treated with a PHILOS plate through a deltopectoral approach. The mean follow-up time was 467 days. The primary endpoint was HHN.ResultsHHN was diagnosed in 12 patients (4%), 10 of which were diagnosed within the first year and one case 4 years after surgery. A positive correlation (p < 0.04) was found between HHN and fracture type (both in AO and Neer’s classification), initial neck-shaft-angle (NSA) and metaphyseal head extension (MHE). Medial hinge displacement (MHD) occurred in all HHN cases. Achieving perfect reduction (< 2 mm dislocation) was relevant to avoiding HHN (p = 0.035). Although HHN developed in 32% of the high risk cases (four-part fractures with a short MHE), it was completely avoided (0%) when perfect reduction was achieved. Time until surgery after admission was neither a protective nor a risk factor for HHN.ConclusionWe conclude that fracture complexity (four-part and C-fractures) as well as disruption of the medial hinge with a metaphyseal head extension smaller than 8 mm are relevant risk factors for humerus head necrosis. A combination of these criteria generated an high risk pattern with a 32% rate of HHN. Though often difficult to achieve, perfect reduction was a clear protective factor and reduced HHN to 0%. Perfect reduction may be key to inosculation and, therefore, salvage of the humerus head, especially in high risk cases. Surgery timing did not correlate with HHN.Level of EvidenceLevel 3, retrospective cohort study.     

Inflammatory myofibroblastic tumor of the pancreas with regional lymph node involvement

Inflammatory myofibroblastic tumors (IMT) can be found in virtually any location of the human body. Histologically a mesenchymal aspect predominates and makes these mostly benign tumors apt to be erroneously diagnosed as a soft tissue sarcoma. Cases showing infiltrative growth and local recurrence further complicate the assessment. Localization of an IMT in the pancreas is extremely rare. Clinical investigations regularly lead to the putative diagnosis of a malignant tumor and only subsequent histological examination can establish the correct tumor classification. We present the case of a 62-year-old woman with IMT of the pancreas. Evidence of lymph node involvement has not yet been reported in this setting.     

Gene conversion is a likely cause of mutation in PKD1

Approximately 70% of the gene responsible for the most common form of autosomal dominant polycystic kidney disease ( PKD1 ) is replicated in several highly homologous copies located more proximally on chromosome 16. We recently have described a novel technique for mutation detection in the duplicated region of PKD1 that circumvents the difficulties posed by these homologs. We have used this method to identify two patients with a nearly identical cluster of base pair substitutions in exon 23. Since pseudogenes are known to be reservoirs for mutation via gene conversion events for a number of other diseases, we decided to test whether these sequence differences in PKD1 could have arisen as a result of this mechanism. Using changes in restriction digest patterns, we were able to show that these sequence substitutions are also present in N23HA, a rodent-human somatic cell hybrid that contains only the PKD1 homologs. Moreover, these changes were also detected in total DNA from several affected and unaffected individuals that did not harbor this mutation in their PKD1 gene copy. This is the first example of gene conversion in PKD1 , and our findings highlight the importance of using gene-specific reagents in defining PKD1 mutations.      

Alternative methods for validation of cell culture infection with duck hepatitis B virus

Hepatitis B virus (HBV) is an important virus used in disinfection procedures for blood spillage. However, validation of HBV inactivation is difficult, since there are no feasible infectivity assays. In some countries, the duck HBV (DHBV) is recognized as a suitable model for testing antiviral activity of chemical biocides against HBV. Currently, DHBV-infected ducks are required for preparation of the test virus as well as eggs from DHBV-free flocks for testing DHBV infectivity. To improve the practicality of the system, we suggested to use commercially available embryonated duck eggs for preparation of DHBV-susceptible hepatocyte cultures and to exclude infected hepatocytes by pre-screening with qualitative detection of DHBV DNA using polymerase chain reaction (PCR). A standardized DHBV test virus was prepared from the DHBV DNA-transfected hepatoma cell line D2, which contained 10(11)DHBV DNA molecules per mL detected by light cycler real-time PCR. Infection of cell cultures was most efficient 4 days after plating. The best identification of infected cultures was possible 6 days after infection with immunofluorescence using an antiserum against DHBV surface antigen.     

Phenotype and functional analysis of human monocyte-derived dendritic cells loaded with biodegradable poly(lactide-co-glycolide) microspheres for immunotherapy

Dendritic cells (DC) are increasingly explored as cellular vaccines for tumor immunotherapy. In most reported DC-based cancer vaccine trials, DC have been pulsed with soluble tumor antigen-derived peptide ligands of MHC molecules. Considering that the half-life of peptide/MHC complexes on the cell surface is relatively short and that soluble exogenous protein antigens cannot be efficiently processed via the MHC class I-processing pathway, the current vaccination procedure is not optimal for the induction of strong T cell responses aiming at tumor rejection. Recently, we have shown that antigen presentation can be prolonged when synthetic peptides were encapsulated in biodegradable poly(D,L-lactide-co-glycolide) (PLGA) microspheres (MS) for uptake by DC. In the present study, we investigated the phenotypic and functional consequences of MS uptake by human monocyte-derived dendritic cells (MoDC) in vitro. We found that immature MoDC that were prepared in serum free media suitable for clinical application were able to phagocytose high numbers of MS, while matured MoDC showed a reduced capacity for phagocytosis of MS. The ingestion of MS did not change the cell surface expression of CD80, CD83, CD86 and HLA-DR of immature and mature DC, suggesting that MS uptake did not induce DC maturation but that maturation by cytokines or LPS was unaltered in the presence of MS. Furthermore, MS-loaded mature MoDC expressed normal levels of the chemokine receptor CCR7 and migrated as efficiently towards CCL19 or CCL21 as unloaded MoDC. DC viability and the secretion of TNF-alpha and IL-12 was not significantly changed by MS loading. Taken together, our data indicate that PLGA-MS loading has no negative effects on the pivotal properties of MoDC in vitro. It should therefore be feasible to further develop this antigen loading strategy for clinical use in immunotherapy against viral infections and tumors.     

Coxsackievirus B3-induced myocarditis in MHC class II-deficient mice

OBJECTIVES: The pathogenesis of coxsackievirus B3 (CVB3)-induced myocarditis was investigated in immunocompetent C57BL/6 and MHC class II knockout mice with identical genetic backgrounds. STUDY DESIGN/METHODS: We analyzed the histology and immunohistology of myocardial injury, the replicating virus titer, and antibody response in the early and late phase of disease. RESULTS: CVB3-infected C57BL/6 mice showed acute myocarditis, with spontaneous healing, virus elimination, anti-CVB3 IgM/IgG production, and neutralizing antibody response. In contrast, MHC class II knockout mice developed less severe acute myocarditis, persistence of infiltrations and strong fibrosis, virus persistence, and weak IgG response, with absence of virus neutralizing antibodies. CONCLUSIONS: Immunodeficient organisms are more susceptible to long-term heart muscle injuries after infection with CVB3. The presence of CD4+ T cells are necessary to prevent the development of chronic disease.     

Endoplasmic reticulum chaperone gp96 in macrophages is essential for protective immunity during Gram‐negative pneumonia

Klebsiella pneumoniae is among the most common Gram‐negative bacteria that cause pneumonia. Gp96 is an endoplasmic reticulum chaperone that is essential for the trafficking and function of Toll‐like receptors (TLRs) and integrins. To determine the role of gp96 in myeloid cells in host defence during Klebsiella pneumonia, mice homozygous for the conditional Hsp90b1 allele encoding gp96 were crossed with mice expressing Cre‐recombinase under control of the LysM promoter to generate LysMcre‐Hsp90b1‐flox mice. LysMcre‐Hsp90b1‐flox mice showed absence of gp96 protein in macrophages and partial depletion in monocytes and granulocytes. This was accompanied by almost complete absence of TLR2 and TLR4 on macrophages. Likewise, integrin subunits CD11b and CD18 were not detectable on macrophages, while being only slightly reduced on monocytes and granulocytes. Gp96‐deficient macrophages did not release pro‐inflammatory cytokines in response to Klebsiella and displayed reduced phagocytic capacity independent of CD18. LysMcre‐Hsp90b1‐flox mice were highly vulnerable to lower airway infection induced by K. pneumoniae, as reflected by enhanced bacterial growth and a higher mortality rate. The early inflammatory response in Hsp90b1‐flox mice was characterized by strongly impaired recruitment of granulocytes into the lungs, accompanied by attenuated production of pro‐inflammatory cytokines, while the inflammatory response during late‐stage pneumonia was not dependent on the presence of gp96. Blocking CD18 did not reproduce the impaired host defence of LysMcre‐Hsp90b1‐flox mice during Klebsiella pneumonia. These data indicate that macrophage gp96 is essential for protective immunity during Gram‐negative pneumonia by regulating TLR expression. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.