Catastrophic Femoral Head-Stem Trunnion Dissociation Secondary to Corrosion.

BACKGROUND: Modular femoral heads provide procedural enhancement by allowing accurate restoration of hip offset and limb-length equalization. However, corrosion may lead to adverse local tissue reactions. Severe trunnion corrosion can also lead to femoral head dissociation and catastrophic implant failure following primary total hip arthroplasty. METHODS: We describe 5 cases, from our institution, in which the femoral head became dissociated from the femoral stem trunnion secondary to severe corrosion. Possible causes are evaluated. RESULTS: Demographic commonalities among the 5 patients included a body mass index (BMI) of ≥30 kg/m(2) and male sex. All femoral heads were made of cobalt-chromium alloy and were larger-diameter implants (≥36 mm). Four of the 5 patients had a femoral head that increased the neck length above the default on a so-called standard head and 3 of the 5 had a stem with a 127° neck-shaft angle. CONCLUSIONS: Although dissociation of the femoral head from the femoral trunnion following total hip arthroplasty is exceedingly rare, the prevalence may increase with longer follow-up. The dissociation is likely related to multiple factors, including a BMI of ≥30 kg/m(2), male sex, and corrosion resulting from the use of a larger metal head with a neck length of greater than the default and a stem with high offset. It is critical that surgeons be able to recognize this mode of implant failure and appropriately prepare to remove the femoral component during revision surgery. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence

Reactive scoliosis: a challenging phenomenon in adolescent patients with hip arthritis

Functional limb length discrepancy (LLD) in adolescents can result from soft tissue contracture following long-standing hip disease. We present a case of a 13-year-old girl with difficulty in ambulation due to right hip pain and LLD. Radiographs revealed severe arthritis of right hip with signs of avascular necrosis of the femoral head. The patient had developed reactive scoliosis of lumbar spine along with pelvic obliquity. After failing conservative management, total hip arthroplasty (THA) without attempting to equalize LLD was performed. At 6-month follow-up, patient was pain free with full range of motion and her functional LLD was completely resolved. In such adolescent patients, reactive scoliosis of spine is reversible, and with no evidence of true LLD, THA without correcting LLD should be the right choice

Reconstruction of a polyclonal ADCC antibody repertoire from an HIV-1 non-transmitting mother

Summary: Human natural history and vaccine studies support a protective role of antibody dependent cellular cytotoxicity (ADCC) activity against many infectious diseases. One setting where this has consistently been observed is in HIV-1 vertical transmission, where passively acquired ADCC activity in HIV-exposed infants has correlated with reduced acquisition risk and reduced pathogenesis in HIV+ infants. However, the characteristics of HIV-specific antibodies comprising a maternal plasma ADCC response are not well understood. Here, we reconstructed monoclonal antibodies (mAbs) from memory B cells from late pregnancy in mother MG540, who did not transmit HIV to her infant despite several high-risk factors. Twenty mAbs representing 14 clonal families were reconstructed, which mediated ADCC and recognized multiple HIV Envelope epitopes. In experiments using Fc-defective variants, only combinations of several mAbs accounted for the majority of plasma ADCC of MG540 and her infant. We present these mAbs as evidence of a polyclonal repertoire with potent HIV-directed ADCC activity

PhyloMagnet : fast and accurate screening of short-read meta-omics data using gene-centric phylogenetics

Motivation: Metagenomic and metatranscriptomic sequencing have become increasingly popular tools for producing massive amounts of short-read data, often used for the reconstruction of draft genomes or the detection of (active) genes in microbial communities. Unfortunately, sequence assemblies of such datasets generally remain a computationally challenging task. Frequently, researchers are only interested in a specific group of organisms or genes; yet, the assembly of multiple datasets only to identify candidate sequences for a specific question is sometimes prohibitively slow, forcing researchers to select a subset of available datasets to address their question. Here, we present PhyloMagnet, a workflow to screen meta-omics datasets for taxa and genes of interest using genecentric assembly and phylogenetic placement of sequences. Results: Using PhyloMagnet, we could identify up to 87% of the genera in an in vitro mock community with variable abundances, while the false positive predictions per single gene tree ranged from 0 to 23%. When applied to a group of metagenomes for which a set of metagenome assembled genomes (MAGs) have been published, we could detect the majority of the taxonomic labels that the MAGs had been annotated with. In a metatranscriptomic setting, the phylogenetic placement of assembled contigs corresponds to that of transcripts obtained from transcriptome assembly