Infection and Mortality Rate in Hepatitis C and Cirrhotic Patients Undergoing Hip and Knee Replacement.

Liver disease carries significant risk in total joint arthroplasty (TJA). The authors sought to investigate the complications in hepatitis C virus (HCV) and cirrhosis patients after TJA. PRISMA guidelines extracted ten studies and meta-analytic analysis was performed. Five hundred and twenty-seven patients with liver disease underwent TJA. The complication rate was 38.9%, with 8% infection at 57 months. Cirrhotic patients had higher complication and infection rates compared to HCV patients (p < 0.001, p < 0.039, respectively). Mortality in cirrhosis patients was 17.8% at 36 months. Studies suggested Child Pugh Class A patients had significantly lower complications than Class B or C. One study revealed lower MELD (Model for End-Stage Liver Disease) scores < 10 carry a low mortality risk of 9.8% compared with 32% mortality if MELD score 10 or above. Cirrhosis has significant infection and mortality risk in total hip and knee arthroplasty. Surgeons can risk stratify these patients by MELD score and Child Pugh Class. (Journal of Surgical Orthopaedic Advances 31(1):001-006, 2022).

Highly Porous Metaphyseal Cones in Revision Total Knee Arthroplasty: A Case Series.

Highly porous metaphyseal cones are used for the management of large bone defects in revision total knee arthroplasty. These cones fill defects and allow bony ongrowth while providing several sizing and offset options. In this case series, we evaluated three patients who received these latest generation metaphyseal cones. Specifically, these cases will be explored in detail with respect to history, indications, operative technique, and short-term outcomes. Overall, these newer generation porous coated cones are excellent options for large contained bone loss in the absence of infection, and they have demonstrated good clinical and radiological outcomes at short-term follow-up.

Tantalum Cones in Revision Total Knee Arthroplasty.

The best strategy to address large bony defects in revision total knee arthroplasty has yet to be determined. The relatively recent development of porous tantalum cones and their use to address massive bone loss in knee arthroplasty has shown promising short- and intermediate-term results. The purpose of this review is to present the current literature on: (1) basic science of porous tantalum, (2) classification and treatment for bone loss, (3) clinical results, and (4) evolution of newer generation cones.

3D silicon neural probe with integrated optical fibers for optogenetic modulation.

Optogenetics is a powerful modality for neural modulation that can be useful for a wide array of biomedical studies. Penetrating microelectrode arrays provide a means of recording neural signals with high spatial resolution. It is highly desirable to integrate optics with neural probes to allow for functional study of neural tissue by optogenetics. In this paper, we report the development of a novel 3D neural probe coupled simply and robustly to optical fibers using a hollow parylene tube structure. The device shanks are hollow tubes with rigid silicon tips, allowing the insertion and encasement of optical fibers within the shanks. The position of the fiber tip can be precisely controlled relative to the electrodes on the shank by inherent design features. Preliminary in vivo rat studies indicate that these devices are capable of optogenetic modulation simultaneously with 3D neural signal recording.

The microfluidic multitrap nanophysiometer for hematologic cancer cell characterization reveals temporal sensitivity of the calcein-AM efflux assay.

Cytometric studies utilizing flow cytometry or multi-well culture plate fluorometry are often limited by a deficit in temporal resolution and a lack of single cell consideration. Unfortunately, many cellular processes, including signaling, motility, and molecular transport, occur transiently over relatively short periods of time and at different magnitudes between cells. Here we demonstrate the multitrap nanophysiometer (MTNP), a low-volume microfluidic platform housing an array of cell traps, as an effective tool that can be used to study individual unattached cells over time with precise control over the intercellular microenvironment. We show how the MTNP platform can be used for hematologic cancer cell characterization by measuring single T cell levels of CRAC channel modulation, non-translational motility, and ABC-transporter inhibition via a calcein-AM efflux assay. The transporter data indicate that Jurkat T cells exposed to indomethacin continue to accumulate fluorescent calcein for over 60 minutes after calcein-AM is removed from the extracellular space.

Marinobufagenin stimulates fibroblast collagen production and causes fibrosis in experimental uremic cardiomyopathy.

We have observed recently that experimental renal failure in the rat is accompanied by increases in circulating concentrations of the cardiotonic steroid, marinobufagenin (MBG), and substantial cardiac fibrosis. We performed the following studies to examine whether MBG might directly stimulate cardiac fibroblast collagen production. In vivo studies were performed using the 5/6th nephrectomy model of experimental renal failure (PNx), MBG infusion (MBG), PNx after immunization against MBG, and concomitant PNx and adrenalectomy. Physiological measurements with a Millar catheter and immunohistochemistry were performed. In vitro studies were then pursued with cultured isolated cardiac fibroblasts. We observed that PNx and MBG increased MBG levels, blood pressure, heart size, impaired diastolic function, and caused cardiac fibrosis. PNx after immunization against MBG and concomitant PNx and adrenalectomy had similar blood pressure as PNx but less cardiac hypertrophy, diastolic dysfunction, and cardiac fibrosis. MBG induced increases in procollagen-1 expression by cultured cardiac fibroblasts at 1 nM concentration. These increases in procollagen expression were accompanied by increases in collagen translation and increases in procollagen-1 mRNA without any demonstrable increase in procollagen-1 protein stability. The stimulation of fibroblasts with MBG could be prevented by administration of inhibitors of tyrosine phosphorylation, Src activation, epidermal growth factor receptor transactivation, and N-acetyl cysteine. Based on these findings, we propose that MBG directly induces increases in collagen expression by fibroblasts, and we suggest that this may be important in the cardiac fibrosis seen with experimental renal failure.