Optimizing protein crosslinking control: Synergistic quenching effects of glycine, histidine, and lysine on glutaraldehyde reactions.

Glutaraldehyde (GA) is a protein crosslinker widely used in biochemical and pharmaceutical research because it can rapidly stabilize and immobilize substrates via amine group interactions. However, controlling GA crosslinking is challenging owing to its swift reactivity and the influence of various solution conditions, such as pH and concentrations of the substrate and crosslinker. Although extensive research has focused on GA cross-linking mechanisms, studies on quenching, which is critical for preventing non-specific aggregation during prolonged storage, remain sparse. This study examines the quenching efficiency of a combined amino acid mixture of glycine, histidine, and lysine, which are commonly used as individual quenchers. Our findings, confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis, demonstrate that this amino acid blend offers superior quenching compared to single amino acids, enhancing quenching activity across a wide pH spectrum. These results provide a novel approach for mitigating the high reactivity of GA with implications for improving sample preservation and stabilization in a range of biochemical applications, including microscopy and cell fixation.

Effects of dexmedetomidine on A549 non-small cell lung cancer growth in a clinically relevant surgical xenograft model.

The perioperative milieu following curative lung cancer surgery is accompanied by a stress response. Inflammasomes mediate inflammation resulting in the unfavorable immunomodulation of natural killer (NK) cell activity, thus promoting cancer progression. This study aimed to investigate the effects of dexmedetomidine (DEX) on the innate immune system, chronic inflammation, and lung cancer progression in a clinically relevant human-to-mouse xenograft model. The human lung cancer cell line A549-luc was subcutaneously injected into BALB/c nude mice. Saline or dexmedetomidine was administered for 2 weeks via an implanted osmotic minipump. After 4 weeks, the tumor size and weight were measured. NK cell activity, serum interferon-γ, interleukin (IL)-1ß and tumor necrosis factor (TNF)-α levels were also measured. IL-10, IL-18, and inflammasome expression levels were assessed in the tumor tissues. DEX caused a decrease in tumor size, tumor weight, and IL-1ß and TNF-α levels and an increase in NK cell activity and IFN-γ level. IL-10 and IL-18 expression was significantly decreased in the DEX-treated group. NLRP3, CTP1A, TXNIP, ASC, IL-1ß, and caspase-1 protein levels were decreased in the DEX-treated group. In conclusion, the use of DEX for 2 weeks inhibited lung cancer progression by suppressing inflammasome- and IL-1ß signaling-induced inflammation and enhancing NK cell activity.

Hemodynamic management during off-pump coronary artery bypass surgery: a narrative review of proper targets for safe execution and troubleshooting.

Off-pump coronary surgery requires mechanical cardiac displacement, which results in bi-ventricular systolic and diastolic dysfunction. Although transient, subsequent hemodynamic deterioration can be associated with poor prognosis and, in extreme cases, emergency conversion to on-pump surgery, which is associated with high morbidity and mortality. Thus, appropriate decision-making regarding whether the surgery can be proceeded based on objective hemodynamic targets is essential before coronary arteriotomy. For adequate hemodynamic management, avoiding myocardial oxygen supply-demand imbalance, which includes maintaining mean arterial pressure above 70 mmHg and preventing an increase in oxygen demand beyond the patient's coronary reserve, must be prioritized. Maintaining mixed venous oxygen saturation above 60%, which reflects the lower limit of adequate global oxygen supply-demand balance, is also essential. Above all, severe mechanical cardiac displacement incurring compressive syndromes, which cannot be overcome by adjusting major determinants of cardiac output, should be avoided. An uncompromising form of cardiac constraint can be ruled out as long as the central venous pressure is not equal to or greater than the pulmonary artery diastolic (or occlusion) pressure, as this would reflect tamponade physiology. In addition, transesophageal echocardiography should be conducted to rule out mechanical cardiac displacement-induced ventricular interdependence, dyskinesia, severe mitral regurgitation, and left ventricular outflow tract obstruction with or without systolic motion of the anterior leaflet of the mitral valve, which cannot be tolerated during grafting. Finally, the ascending aorta should be carefully inspected for gas bubbles to prevent hemodynamic collapse caused by a massive gas embolism obstructing the right coronary ostium.

Impact of transient decrease in mixed venous oxygen saturation on prognosis in off-pump coronary artery bypass surgery: a retrospective cohort study.

BACKGROUND: The prognostic consequences of transient hemodynamic deterioration due to cardiac displacement, which is most severe during left circumflex artery (LCX) grafting in off-pump coronary artery bypass surgery (OPCAB) are unknown. This study aimed to investigate the association between mixed venous oxygen saturation (SvO2) < 60% during LCX grafting and the occurrence of composite of morbidity endpoints. METHODS: Data of patients who underwent elective OPCAB between January 2010 and December 2019 were reviewed. Logistic regression analysis was performed to detect risk factors for the composite of morbidity endpoints, defined as 30-day or in-hospital mortality, postoperative myocardial infarction, prolonged mechanical ventilation > 24 h, cerebrovascular accident, and acute kidney injury. RESULTS: Among 1,071 patients, the composite of morbidity endpoints occurred in 303 (28%) patients. SvO2 < 60% during LCX grafting was significantly associated with the composite of morbidity (OR: 2.72, 95% CI [1.60, 4.61], P < 0.001) along with advanced age, chronic kidney disease, ratio of early mitral inflow velocity to mitral annular early diastolic velocity, and EuroSCORE II. Other major hemodynamic variables including the cardiac index were not associated with the outcome. Additional regression analysis revealed pre-operative anemia as a predictor of SvO2 < 60% during LCX grafting (OR: 2.09, 95% CI [1.33, 3.29], P = 0.001). CONCLUSIONS: A decrease in SvO2 < 60%, albeit confined to the period of cardiac displacement, was associated with a 2.7-fold increased risk of detrimental outcomes after OPCAB, implying the prognostic importance of this transient deterioration in oxygen supply-demand balance.

Studies of functional properties of espin 1: Its interaction to actin filaments.

Actin is a multifunctional biomolecule that forms not only basic structural bodies such as filopodia and lamellipodia, but also large microvilli-like organelles like stereocilia. Actin consists of four sub-domains (S1, S2, S3, and S4), and the "target-binding groove" formed between S1 and S3 is the major binding site for various actin binding proteins. Actin filament dynamics are regulated by numerous actin binding proteins with different mechanisms of actin binding, assembly, and disassembly such as actin severing, branching, and bundling. Ectoplasmic specialization protein 1 (espin 1) is an actin binding and bundling protein that is specifically implicated in the elongation and stabilization of stereocilia as a binding partner with myosin III. However, little is known about the molecular structure, actin bundling, and stabilizing mechanism of espin 1; hence, we investigated the interaction between actin and espin 1 through structural data. In this study, we first purified human espin 1 in an E. coli system following a new detergent-free approach and then demonstrated the 2D structure of full-length espin 1 using transmission electron microscopy along with Nickel nitrilotriacetic acid nanogold labeling and 2D averaging using SPIDER. Furthermore, we also determined the espin 1 binding domain of actin using a co-sedimentation assay along with gelsolin and myosin S1. These findings are not only beneficial for understanding the actin binding and bundling mechanism of espin 1, but also shed light on its elongation, stabilization, and tip-localization mechanisms with myosin III. This study thus provides a basis for understanding the molecular structure of espin 1 and can contribute to various hearing-related diseases, such as hearing loss and vestibular dysfunction.

Impact of preoperative nutritional scores on 1-year postoperative mortality in patients undergoing valvular heart surgery.

OBJECTIVE: Malnutrition is a well-recognized risk factor for poor prognosis and mortality. We investigated whether preoperative malnutrition diagnosed with objective nutritional scores affects 1-year mortality in patients undergoing valvular heart surgery. METHODS: In this retrospective cohort observational study, we evaluated the association among the Controlling Nutritional Status score, Prognostic Nutritional Index, and Geriatric Nutritional Risk Index with 1-year mortality in 1927 patients undergoing valvular heart surgery. We identified factors for mortality using multivariable Cox proportional hazard analysis and investigated the utility of nutritional scores for risk stratification. RESULTS: Malnutrition, as identified by a high Controlling Nutritional Status score and low Prognostic Nutritional Index and Geriatric Nutritional Risk Index, was significantly associated with higher 1-year mortality. Kaplan-Meier survival curve showed that mortality significantly increased as the severity of malnutrition increased (log-rank test, P < .001). The predicted discrimination (C-index) was 0.79 with the Controlling Nutritional Status score, 0.77 with the Prognostic Nutritional Index, and 0.73 with the Geriatric Nutritional Risk Index. Each nutritional index (Controlling Nutritional Status; hazard ratio, 1.31, 95% confidence interval, 1.21-1.42, P < .001), the European System for Cardiac Operative Risk Evaluation II (hazard ratio, 1.07, 95% confidence interval, 1.04-1.09, P < .001), and chronic kidney disease (hazard ratio, 2.26, 95% confidence interval, 1.31-3.90, P = .003) were independent risk factors for mortality. The Controlling Nutritional Status score added to the European System for Cardiac Operative Risk Evaluation II significantly increased the predictive discrimination ability for mortality (C-index 0.82, 95% confidence interval, 0.78-0.87, P = .014) compared with the Controlling Nutritional Status or European System for Cardiac Operative Risk Evaluation II alone. CONCLUSIONS: Preoperative malnutrition as assessed by objective nutritional scores was associated with 1-year mortality after valvular heart surgery. The Controlling Nutritional Status score had the highest predictive ability and, when added to the European System for Cardiac Operative Risk Evaluation II, provided more accurate risk stratification.

Suture anchor fixation of comminuted inferior pole patella fracture-novel technique: suture bridge anchor fixation technique.

PURPOSE: Comminuted inferior pole fractures of the patella are notorious fractures where it is difficult to obtain rigid internal fixation by conventional tension band wiring. The purpose of this study is to evaluate the clinical and radiological outcomes of the suture bridge anchor fixation for these comminuted inferior pole fractures of the patella. METHODS: From March 2012 to December 2018, suture bridge anchor fixation for the inferior pole comminuted fracture of the patella was performed in 22 patients. There were 21 patients of inferior pole comminuted fracture and 1 patient of lower periosteal sleeve avulsion fracture. Clinical outcomes including SF-36 score, Knee injury and osteoarthritis outcome score (KOOS) and post-operative range of motion were evaluated. In all patients, suture bridge anchor fixation was performed and, tension band wiring with K wire was added for large fragment fixation in two patients. We evaluated bony union, the patellar height using Insall-Salvati ratio and its complications. RESULTS: Mean age was 46 ± 20 (15-82) years. Mean follow-up period was 25 ± 18 (11-74) months. In all patients, bony union was achieved at postoperative 4 months. At final follow-up, mean SF-36 score was 72 ± 15 (30-91) points and KOOS score was 66.7 ± 16 (43-97). The average range of motion was 134 ± 5 (125-140) degrees. As a complication, one patient developed a wound infection and subsequent osteomyelitis of inferior pole fracture fragment. Compared to the normal knee, the Insall-Salvati ratio of the injured knee averages 0.73 and this smaller ratio less than 0.8 meant patella baja. CONCLUSIONS: In the comminuted inferior pole fractures of the patella, suture bridge anchor fixation showed good bony union and satisfactory clinical outcomes at the short-term follow-up and could be a satisfactory alternative treatment option. Even though suture bridge anchor fixation in these fractures caused decreased Insall-Salvati ratio (patella height), any patellofemoral pain and limited range of motion was not developed. LEVEL OF EVIDENCE: Level IV.

Perioperative management of patients receiving non-vitamin K antagonist oral anticoagulants: up-to-date recommendations.

Indications of non-vitamin K antagonist oral anticoagulants (NOACs), consisting of two types: direct thrombin inhibitor (dabigatran) and direct factor Xa inhibitor (rivaroxaban, apixaban, and edoxaban), have expanded over the last few years. Accordingly, increasing number of patients presenting for surgery are being exposed to NOACs, despite the fact that NOACs are inevitably related to increased perioperative bleeding risk. This review article contains recent clinical evidence-based up-to-date recommendations to help set up a multidisciplinary management strategy to provide a safe perioperative milieu for patients receiving NOACs. In brief, despite the paucity of related clinical evidence, several key recommendations can be drawn based on the emerging clinical evidence, expert consensus, and predictable pharmacological properties of NOACs. In elective surgeries, it seems safe to perform high-bleeding risk surgeries 2 days after cessation of NOAC, regardless of the type of NOAC. Neuraxial anesthesia should be performed 3 days after cessation of NOACs. In both instances, dabigatran needs to be discontinued for an additional 1 or 2 days, depending on the decrease in renal function. NOACs do not require a preoperative heparin bridge therapy. Emergent or urgent surgeries should preferably be delayed for at least 12 h from the last NOAC intake (better if > 24 h). If surgery cannot be delayed, consider using specific reversal agents, which are idarucizumab for dabigatran and andexanet alfa for rivaroxaban, apixaban, and edoxaban. If these specific reversal agents are not available, consider using prothrombin complex concentrates.

Short-term Outcomes of Ceramic Coated Metal-on-Metal Large Head in Total Hip Replacement Arthroplasty.

PURPOSE: This study characterizes the short-term outcomes of ceramic coated metal-on-metal (MoM) large head total hip arthroplasty (THA) in prospectively selected patients aged 70 to 75 years. MATERIALS AND METHODS: Eighteen patients (18 hips) between the ages of 70 and 75-years old with THA using ceramic-coated MoM large heads between June 2014 and December 2014 were evaluated. We prospectively selected patients younger than 70 years for bipolar hemiarthroplasty and older than 75 years for conventional THA. There were one case of osteoarthritis, 8 cases of femur neck fracture, and 9 cases of intertrochanteric fracture. All patients underwent clinical and radiological follow-up at 6 weeks, 6 and 12 months, and every year postoperatively. The mean duration of follow-up was 24.2 months (range, 18-34 months). RESULTS: The average Harris hip score at the final follow-up was 81.0, except one case which was ultimately converted to conventional THA due to acetabular cup loosening. Radiographically, mean acetabular cup inclination was 45.8°(range, 38-56°) and anteversion was 20.1° (range, 11-25°). The average femoral head size was 48.7 mm. All stems were neutral-positioned except 1 varus-positioned stem. There was 1 case of a soft tissue infection, 3 patients complained of persistent groin pain, and no dislocations occurred. CONCLUSION: Ceramic coated large MOM articulation (ACCIS) have many complications: cup loosening, groin pain, which can lead to fatal outcomes in the elderly patients. Especially in patients with communicated intertrochanter fracture (AO 31-A22, 23), careful attention should be paid to the choice of surgical option.

An anatomic and clinical study of the suprascapular and axillary nerve blocks for shoulder arthroscopy.

HYPOTHESIS: The combination of suprascapular nerve block (SSNB) and axillary nerve block (ANB) has been reported to provide safe and effective analgesia for arthroscopic shoulder surgery. This study was designed to identify anatomic landmarks of the suprascapular nerve (SSN) and axillary nerve (AN) and to evaluate the effects of SSNB and ANB using the identified landmarks. MATERIALS AND METHODS: This study included 52 cadaveric shoulders and 30 patients in the anatomic and clinical studies, respectively. After the exact location of the SSN and AN was identified from the cadavers, the clinical study at the end of the operation and at 8, 16, 24, 32, 40, and 48 hours postoperatively was performed in 2 groups: without both SSNB and ANB (group I) and with both SSNB and ANB (group II). RESULTS: The SSN was located at a length of one-half (2/5-3/5, 88%) from the anterior tip of the acromion to the superior angle of the scapula and at a length of two-fifths (1/3-1/2, 100%) from the anterior tip of the acromion to the medial border of the spine. The AN was located at a length of three-fifths (2/5-4/5, 98%) from the acromial angle to the inferior insertion of the teres major muscle. The depth from the skin was 3.20 ± 0.58 cm for the SSN and 2.07 ± 0.45 cm for the AN. The clinical study showed that the total amount of analgesic for patient-controlled anesthesia was markedly decreased at the end of the operation and at 8 hours postoperatively in group II compared with group I. CONCLUSIONS: The SSNB and ANB were considered to provide safe and effective analgesia in terms of early postoperative pain in arthroscopic shoulder surgery.