Saddle to Incision Relationship: A Novel Approach to Localizing the Incision for Direct Anterior Hip Arthroplasty.

The direct anterior approach for total hip arthroplasty has grown in popularity over the last decade. Incision for this approach is often based on a standardized distance from the anterior superior iliac spine. Despite this method, wound complications remain a known complication during direct anterior approach. We describe a simple and reproducible technique using fluoroscopy to identify the incision during direct anterior total hip arthroplasty. This method allows for accurate placement of incision while adding only a minimal amount of time to the procedure. Using this technique helps minimize proximal skin maceration and lessens the need for extension of incision intraoperatively.

Distal fibular excision: A review of the literature and presentation of our reconstruction technique case series.

Distal fibula resection is a procedure that has been described as early as 1938 for the treatment of neoplastic lesions. There have been several techniques described for the reconstruction of the remaining tibiotalar joint to prevent deformity and maintain as much function as possible. While these reconstruction techniques provide an option for limb salvage with the removal of disease, patients are faced with chronic pain, loss of function, valgus instability, need for long term orthosis, early arthritis, or significant morbidity related to proximal dissection and disruption of native knee anatomy. We present a case series that is compliant with PROCESS1 criteria to demonstrate the effective treatment with distal fibular excision and a reconstruction technique inspired by the original Tommy John procedure of the elbow. This procedure has allowed these two patients long-term stability of the ankle, maintenance of full function, and high levels of function. The first case is a 23-year-old female with high-grade osteosarcoma and the second patient is a 19-year-old female with Ewing sarcoma. Details of the procedure as well as clinical and radiographic follow up of these two patients will be described.

Primary Repair of the Medial Collateral Ligament with a Double Row Suture Technique and Suture Tape Augmentation for Acute Tibial-Sided Injuries.

The management of medial collateral ligament (MCL) injuries has evolved during the past 30 years. Most heal reliably with conservative management. The treatment of MCL sprains with concomitant other ligamentous injuries continues to be controversial. Surgical management of chronic laxity of the medial structures can be quite difficult, and therefore anatomic repair of the medial support structures in the acute setting is preferred when indicated. Complete avulsion of the superficial and deep MCL from the tibia with disruption of the meniscal coronary ligament have a poor prognosis with non-operative treatment and may be optimally managed with acute surgical repair for improved valgus stability. A recent review demonstrated that there is a role for primary MCL repair for select patients. This technique addresses complete avulsions from the tibia, using multiple anchors for anatomic reattachment of the deep and superficial MCL, SutureBridge construct to enhance footprint compression, and suture tape to augment the MCL repair. Advantages of this technique include utilization of suture tape augmentation to allow for early range of motion, maintenance of the native MCL to preserve proprioception, and repair in the acute setting for faster recovery.

SCoPE-MS: mass spectrometry of single mammalian cells quantifies proteome heterogeneity during cell differentiation.

Some exciting biological questions require quantifying thousands of proteins in single cells. To achieve this goal, we develop Single Cell ProtEomics by Mass Spectrometry (SCoPE-MS) and validate its ability to identify distinct human cancer cell types based on their proteomes. We use SCoPE-MS to quantify over a thousand proteins in differentiating mouse embryonic stem cells. The single-cell proteomes enable us to deconstruct cell populations and infer protein abundance relationships. Comparison between single-cell proteomes and transcriptomes indicates coordinated mRNA and protein covariation, yet many genes exhibit functionally concerted and distinct regulatory patterns at the mRNA and the protein level.

Single cell protein analysis for systems biology.

The cellular abundance of proteins can vary even between isogenic single cells. This variability between single-cell protein levels can have regulatory roles, such as controlling cell fate during apoptosis induction or the proliferation/quiescence decision. Here, we review examples connecting protein levels and their dynamics in single cells to cellular functions. Such findings were made possible by the introduction of antibodies, and subsequently fluorescent proteins, for tracking protein levels in single cells. However, in heterogeneous cell populations, such as tumors or differentiating stem cells, cellular decisions are controlled by hundreds, even thousands of proteins acting in concert. Characterizing such complex systems demands measurements of thousands of proteins across thousands of single cells. This demand has inspired the development of new methods for single-cell protein analysis, and we discuss their trade-offs, with an emphasis on their specificity and coverage. We finish by highlighting the potential of emerging mass-spec methods to enable systems-level measurement of single-cell proteomes with unprecedented coverage and specificity. Combining such methods with methods for quantitating the transcriptomes and metabolomes of single cells will provide essential data for advancing quantitative systems biology.

Regional alterations in purkinje cell density in patients with autism.

Neuropathological studies, using a variety of techniques, have reported a decrease in Purkinje cell (PC) density in the cerebellum in autism. We have used a systematic sampling technique that significantly reduces experimenter bias and variance to estimate PC densities in the postmortem brains of eight clinically well-documented individuals with autism, and eight age- and gender-matched controls. Four cerebellar regions were analyzed: a sensorimotor area comprised of hemispheric lobules IV-VI, crus I & II of the posterior lobe, and lobule X of the flocculonodular lobe. Overall PC density was thus estimated using data from all three cerebellar lobes and was found to be lower in the cases with autism as compared to controls, an effect that was most prominent in crus I and II (p<0.05). Lobule X demonstrated a trend towards lower PC density in only the males with autism (p = 0.05). Brain weight, a correlate of tissue volume, was found to significantly contribute to the lower lobule X PC density observed in males with autism, but not to the finding of lower PC density in crus I & II. Therefore, lower crus I & II PC density in autism is more likely due to a lower number of PCs. The PC density in lobule X was found to correlate with the ADI-R measure of the patient's use of social eye contact (R²â€Š= -0.75, p = 0.012). These findings support the hypothesis that abnormal PC density may contribute to selected clinical features of the autism phenotype.

Acute metabolic decompensation due to influenza in a mouse model of ornithine transcarbamylase deficiency.

The urea cycle functions to incorporate ammonia, generated by normal metabolism, into urea. Urea cycle disorders (UCDs) are caused by loss of function in any of the enzymes responsible for ureagenesis, and are characterized by life-threatening episodes of acute metabolic decompensation with hyperammonemia (HA). A prospective analysis of interim HA events in a cohort of individuals with ornithine transcarbamylase (OTC) deficiency, the most common UCD, revealed that intercurrent infection was the most common precipitant of acute HA and was associated with markers of increased morbidity when compared with other precipitants. To further understand these clinical observations, we developed a model system of metabolic decompensation with HA triggered by viral infection (PR8 influenza) using spf-ash mice, a model of OTC deficiency. Both wild-type (WT) and spf-ash mice displayed similar cytokine profiles and lung viral titers in response to PR8 influenza infection. During infection, spf-ash mice displayed an increase in liver transaminases, suggesting a hepatic sensitivity to the inflammatory response and an altered hepatic immune response. Despite having no visible pathological changes by histology, WT and spf-ash mice had reduced CPS1 and OTC enzyme activities, and, unlike WT, spf-ash mice failed to increase ureagenesis. Depression of urea cycle function was seen in liver amino acid analysis, with reductions seen in aspartate, ornithine and arginine during infection. In conclusion, we developed a model system of acute metabolic decompensation due to infection in a mouse model of a UCD. In addition, we have identified metabolic perturbations during infection in the spf-ash mice, including a reduction of urea cycle intermediates. This model of acute metabolic decompensation with HA due to infection in UCD serves as a platform for exploring biochemical perturbations and the efficacy of treatments, and could be adapted to explore acute decompensation in other types of inborn errors of metabolism.

Mitochondrial dysfunction in skeletal muscle of amyloid precursor protein-overexpressing mice.

Inclusion body myositis, the most common muscle disorder in the elderly, is partly characterized by abnormal expression of amyloid precursor protein (APP) and intracellular accumulation of its proteolytic fragments collectively known as ß-amyloid. The present study examined the effects of ß-amyloid accumulation on mitochondrial structure and function of skeletal muscle from transgenic mice (MCK-ßAPP) engineered to accumulate intramyofiber ß-amyloid. Electron microscopic analysis revealed that a large fraction of myofibers from 2-3-month-old MCK-ßAPP mice contained numerous, heterogeneous alterations in mitochondria, and other cellular organelles. [(1)H-decoupled](13)C NMR spectroscopy showed a substantial reduction in TCA cycle activity and indicated a switch from aerobic to anaerobic glucose metabolism in the MCK-ßAPP muscle. Isolated muscle fibers from the MCK-ßAPP mice also exhibited a reduction in cytoplasmic pH, an increased rate of ROS production, and a partially depolarized plasmalemma. Treatment of MCK-ßAPP muscle cells with Ru360, a mitochondrial Ca(2+) uniporter antagonist, reversed alterations in the plasmalemmal membrane potential (V(m)) and pH. Consistent with altered redox state of the cells, treatment of MCK-ßAPP muscle cells with glutathione reversed the effects of ß-amyloid accumulation on Ca(2+) transient amplitudes. We conclude that structural and functional alterations in mitochondria precede the reported appearance of histopathological and clinical features in the MCK-ßAPP mice and may represent key early events in the pathogenesis of inclusion body myositis.