Ian Hollyer

All Publications

• Acetabular labral reconstruction with medial meniscal allograft: preliminary results of a new surgical technique. European journal of orthopaedic surgery & traumatology : orthopedie traumatologie Chen, M. J., Hollyer, I., Pun, S. Y., Bellino, M. J. 2021

  Abstract

  PURPOSE: Reconstruction of the acetabular labrum during femoroacetabular impingement (FAI) surgery is accepted when the labrum is deficient and irreparable. Here we describe a novel technique using fresh-frozen medial meniscal allograft for labral reconstruction during surgical hip dislocation for correction of pincer FAI due to acetabular overcoverage.METHODS: The results from seven hips (six patients) that underwent this procedure with 1 year minimum follow-up, and radiographs are presented.RESULTS: Six of the seven hips had improvements in pain, hip flexion, hip abduction, and Merle d'Aubigne-Postel scores. Only one patient with pre-existing osteoarthritis underwent reoperation with conversion to total hip arthroplasty. All digastric trochanteric osteotomies healed, and there were no cases of femoral head osteonecrosis or progression of Tonnis grades.CONCLUSIONS: The medial meniscus is a morphologically and clinically suitable option for labral reconstruction and effectively restores the hip fluid seal.

  View details for DOI 10.1007/s00590-021-02986-2

  View details for PubMedID 34028622

• Management of the posterior wall fracture in associated both column fractures of the acetabulum. European journal of orthopaedic surgery & traumatology : orthopedie traumatologie Chen, M. J., Hollyer, I. n., Wadhwa, H. n., Tigchelaar, S. S., Van Rysselberghe, N. L., Bishop, J. A., Bellino, M. J., Gardner, M. J. 2021

  Abstract

  The primary aim of this study was to compare clinical outcomes in patients with associated both column (ABC) acetabular fractures with fracture of the posterior wall (PW), in which the PW underwent reduction and fragment-specific fixation versus those that were treated with column fixation alone. Secondary aims were to assess PW fracture incidence and morphology, as well as to compare radiographic outcomes including fracture healing and interval displacement of the PW in those that did and did not undergo fragment-specific fixation of the PW.This was a retrospective series of ABC acetabular fractures treated at a single Level I trauma center. Separate fractures of the PW were identified, and associated features were assessed. Associated both column fractures that underwent reduction and fragment-specific fixation of the PW where then compared to ABC fractures with PW involvement that underwent column reconstruction alone. Radiographic and clinical outcomes were compared.Fractures of the PW occurred in 55.7% of ABC fractures and were associated with central displacement of the femoral head. The majority of PW fractures were large and involved the acetabular roof. All PW fractures healed without displacement by 3 months, regardless of whether or not reduction and stabilization was performed. Mid-term outcomes at 1-year were similar regardless of whether or not the PW was reduced and stabilized, with regards to Tönnis grade, Merle d'Aubigné-Postel score, and conversion to total hip arthroplasty.Reduction and fragment-specific fixation of the PW component of ABC acetabular fractures did not improve outcomes in this small comparative study. Posterior wall fractures associated with ABC patterns are frequently large-sized fragments that involve the acetabular roof and are rendered stable after reconstruction of the columns.

  View details for DOI 10.1007/s00590-020-02850-9

  View details for PubMedID 33386470

• Safety and efficacy of methenamine hippurate for the prevention of recurrent urinary tract infections in adult renal transplant recipients: A single center, retrospective study. Transplant infectious disease : an official journal of the Transplantation Society Hollyer, I., Varias, F., Ho, B., Ison, M. G. 2019; 21 (3): e13063

  Abstract

  Recurrent urinary tract infections (UTI) are an important cause of morbidity and mortality in renal transplant recipients (RTR).In this retrospective study we gathered clinical data from patients prescribed methenamine hippurate to prevent recurrent UTI pre- and post-intervention. Thirty-eight RTR ≥18 years old at Northwestern Memorial Hospital from 2006-2017 were included in the final analysis.The median and range for follow-up days were 365 (299-365) pre- vs 314 (105-365) post-methenamine. Total UTI frequency (9.16 vs 5.01/1000 patient follow-up days), days of antibiotic therapy to treat UTI (215 vs 132/1000 patient follow-up days), and hospitalization due to UTI (2.64 vs 1.07/1000 patient follow-up days) decreased while patients took methenamine. Escherichia coli and Klebsiella pneumoniae were the most commonly identified cause of UTI both pre- and post-intervention. Drug resistant bacteria (ESBL-producing or VRE) affected 3 patients pre- and recurred in 1 of those patients plus 3 new patients post-methenamine. Methenamine had few adverse side effects for patients. One patient had nausea and 1 was intolerant.We found that methenamine is well tolerated and is useful in reducing UTI, antibiotic prescriptions, and hospitalization in RTR with recurrent UTI. Larger prospective studies are needed to confirm these findings.

  View details for DOI 10.1111/tid.13063

  View details for PubMedID 30776166

  View details for PubMedCentralID PMC6551271

• The challenge of urinary tract infections in renal transplant recipients. Transplant infectious disease : an official journal of the Transplantation Society Hollyer, I., Ison, M. G. 2018; 20 (2): e12828

  Abstract

  Urinary tract infections (UTI) are an important cause of morbidity and mortality in renal transplant patients. These infections are quite common, and the goal of care is to identify and reduce risk factors while providing effective prophylaxis and treatment. Better understanding of long-term outcomes from these infections has led to the distinctions among UTI, recurrent UTI, and asymptomatic bacteriuria (ASB), and that each requires a different therapeutic approach. Specifically, new research has supported the perspective that asymptomatic bacteriuria should not be treated. Symptomatic UTI, on the other hand, requires intervention and remains an ongoing challenge for infectious disease clinicians. Many bacteria species are responsible for UTI in renal transplant patients, and in recent years there has been a global rise in infection caused by bacteria with newly acquired antibacterial resistance genes. Many renal transplant patients who experience UTI will also have multiple recurring episodes, which likely has a distinct pathophysiological mechanism leading to chronic colonization of the urinary tract. In these cases, long-term management includes bacterial suppression, which aims to reduce rather than eliminate bacteria to levels below the threshold for symptomatic infection. This review will address the current understanding of UTI epidemiology, pathogenesis, and risk factors in the renal transplant community, and also focus on current prevention and treatment strategies for patients who face an environment of increasingly antibiotic-resistant bacteria.

  View details for DOI 10.1111/tid.12828

  View details for PubMedID 29272071

• The human cytoplasmic dynein interactome reveals novel activators of motility. eLife Redwine, W. B., DeSantis, M. E., Hollyer, I., Htet, Z. M., Tran, P. T., Swanson, S. K., Florens, L., Washburn, M. P., Reck-Peterson, S. L. 2017; 6

  Abstract

  In human cells, cytoplasmic dynein-1 is essential for long-distance transport of many cargos, including organelles, RNAs, proteins, and viruses, towards microtubule minus ends. To understand how a single motor achieves cargo specificity, we identified the human dynein interactome by attaching a promiscuous biotin ligase ('BioID') to seven components of the dynein machinery, including a subunit of the essential cofactor dynactin. This method reported spatial information about the large cytosolic dynein/dynactin complex in living cells. To achieve maximal motile activity and to bind its cargos, human dynein/dynactin requires 'activators', of which only five have been described. We developed methods to identify new activators in our BioID data, and discovered that ninein and ninein-like are a new family of dynein activators. Analysis of the protein interactomes for six activators, including ninein and ninein-like, suggests that each dynein activator has multiple cargos.

  View details for DOI 10.7554/eLife.28257

  View details for PubMedID 28718761

  View details for PubMedCentralID PMC5533585

• Cytoplasmic dynein is required for the spatial organization of protein aggregates in filamentous fungi. Cell reports Egan, M. J., McClintock, M. A., Hollyer, I. H., Elliott, H. L., Reck-Peterson, S. L. 2015; 11 (2): 201-9

  Abstract

  Eukaryotes have evolved multiple strategies for maintaining cellular protein homeostasis. One such mechanism involves neutralization of deleterious protein aggregates via their defined spatial segregation. Here, using the molecular disaggregase Hsp104 as a marker for protein aggregation, we describe the spatial and temporal dynamics of protein aggregates in the filamentous fungus Aspergillus nidulans. Filamentous fungi, such as A. nidulans, are a diverse group of species of major health and economic importance and also serve as model systems for studying highly polarized eukaryotic cells. We find that microtubules promote the formation of Hsp104-positive aggregates, which coalesce into discrete subcellular structures in a process dependent on the microtubule-based motor cytoplasmic dynein. Finally, we find that impaired clearance of these inclusions negatively impacts retrograde trafficking of endosomes, a conventional dynein cargo, indicating that microtubule-based transport can be overwhelmed by chronic cellular stress.

  View details for DOI 10.1016/j.celrep.2015.03.028

  View details for PubMedID 25865884

  View details for PubMedCentralID PMC4465048