Structural arrangement of crystalline/amorphous phases of polyethylene-block-polystyrene copolymer as induced by orientation techniques

A polyethylene-block-polystyrene copolymer film having a bicontinuous crystalline/amorphous phases was tensile-drawn under various conditions for the structural arrangement of these phases. The prepared film could be drawn below the melting temperature of the polyethylene component, with the highest drawability obtained at 60ｰC. However, the initial bicontinuous structure was gradually destroyed with increasing strain because the drawing temperature was lower than the glass-transition temperature of the polystyrene component. Correspondingly, a necking phenomenon was clearly recognizable when samples were drawn. In contrast, drawing near the melting temperature of the polyethylene component produced less orientation of both the crystalline and amorphous phases, resulting in homogeneous deformation with lower drawing stress. These results indicated that the modification of the lower ductility of the polystyrene component was key to the effective structural arrangement of both phases by tensile drawing. Here, a solvent-swelling technique was applied to improve polystyrene deformability even below its glass-transition temperature. Tensile drawing after such a treatment successfully induced the orientation of both the crystalline and amorphous phases while retaining their initial continuities. A change in the deformation type from necking to homogeneous deformation was also confirmed for the stress-strain behavior

Osteosynthesis for Geriatric Acetabular Fractures: An Epidemiological and Clinico-Radiological Study Related to Marginal or Roof Impaction

This retrospective study sought to elucidate the incidence rates of roof impaction (RI) and marginal impaction (MI) and radiological and clinical outcomes of open reduction and internal fixation (ORIF) for RI and MI in geriatric acetabular fractures. The cases of 68 patients aged ≥ 65 years (mean 71 years) treated with ORIF were analyzed. MI was present in 12 fractures (67%) and an RI of the weight-bearing surface was present in 24 (46%) of the potential fracture types. Regarding the reduction quality, 54% of the reductions were graded as anatomical, 37% as imperfect, and 9% as poor. In the clinical evaluations of the 45 patients who had > 1-year follow-up (follow-up rate: 66.2%), 18% were graded as excellent, 53% as good, 16% as fair, and 13% as poor. An anatomic reduction was strongly associated with good or excellent clinical and radiological outcomes. CT was superior to radiographs for detecting the residual displacement postoperatively. Postoperative deep infection occurred in four patients. Three patients (6.7%) underwent a total hip arthroplasty conversion due to secondary osteoarthritis of the hip. We recommend ORIF as the preferred surgical treatment option for displaced acetabular fractures in elderly patients

The Masquelet technique for septic arthritis of the small joint in the hands: Case reports

Septic arthritis in distal interphalangeal (DIP) joints sometimes occurs in association with mucous cysts or after the surgical treatment of mallet fingers. Recently, several studies have demonstrated the effectiveness of the Masquelet technique in the treatment of bone defects caused by trauma or infection. However, only few studies have reported the use of this technique for septic arthritis in small joints of the hand, and its effectiveness in treating septic arthritis in DIP joints remains unclear. We report the clinical and radiological outcomes of three patients who were treated with the Masquelet technique for septic arthritis in DIP joints. One patient had uncontrolled diabetes and another had rheumatoid arthritis treated with methotrexate and prednisolone. The first surgical stage involved thorough debridement of the infection site, including the middle and distal phalanx. We placed an external fixator from the middle to the distal phalanx and then packed the cavity of the DIP joint with antibiotic cement bead of polymethylmethacrylate (40 g) including 2 g of vancomycin and 200 mg of minocycline. At 4-6 weeks after the first surgical stage, the infection had cleared, and the second surgical stage was performed. The external fixator and cement bead were carefully removed while carefully preserving the surrounding osteo-induced membrane. The membrane was smooth and nonadherent to the cement block. In the second surgical stage, an autogenous bone graft was harvested from the iliac bone and inserted into the joint space, within the membrane. The bone graft, distal phalanx, and middle phalanx were fixed with Kirschner wires and/or a soft wire. Despite the high risk of infection, bone union was achieved in all patients without recurrence of infection. Although the Masquelet technique requires two surgeries, it can lead to favorable clinical and radiological outcomes for infected small joints of the hand.Septic arthritis in distal interphalangeal (DIP) joints sometimes occurs in association with mucous cysts or after the surgical treatment of mallet fingers. Recently, several studies have demonstrated..

Associations among Preoperative Malnutrition, Muscle Loss, and Postoperative Walking Ability in Intertrochanteric Fractures: A Retrospective Study

Sarcopenia and malnutrition are increasing in older adults and are reported risk factors for functional impairment after hip fracture surgery. This study aimed to investigate the associations between skeletal muscle mass loss, malnutrition, and postoperative walking ability in patients with hip fracture. We retrospectively reviewed patients who underwent intertrochanteric fracture surgery at our institute. The psoas muscle index, controlling nutritional status score, and functional ambulation category (FAC) were used to evaluate skeletal muscle mass, nutritional status, and walking ability, respectively. Six months after surgery, walking ability was assessed as either “gait disturbance” or “independent gait”. Multivariate binomial logistic regression analysis, with skeletal muscle mass, nutritional status, and other factors, was used to predict the risk of being assigned to the gait disturbance group. This study included 95 patients (mean age, 85.2 years; 70 women). Sixty-six patients had low skeletal muscle mass, 35 suffered from malnutrition, and 28 had both. Malnutrition and low skeletal muscle mass were significantly associated with postoperative gait disturbance (FAC < 3). Preoperative low skeletal muscle mass and malnutrition were risk factors for postoperative poor walking ability. Further preventive interventions focusing on skeletal muscle mass and nutritional status are required

Bioavailability of prenyl quercetin

Prenyl flavonoids are widely distributed in plant foods and have attracted appreciable attention in relation to their potential benefits for human health. Prenylation may enhance the biological functions of flavonoids by introducing hydrophobic properties in their basic structures. Previously, we found that 8-prenyl naringenin exerted a greater preventive effect on muscle atrophy than nonprenylated naringenin in a mouse model. Here, we aimed to estimate the effect of prenylation on the bioavailability of dietary quercetin (Q). The cellular uptake of 8-prenyl quercetin (PQ) and Q in Caco-2 cells and C2C12 myotube cells was examined. Prenylation significantly enhanced the cellular uptake by increasing the lipophilicity in both cell types. In Caco-2 cells, efflux of PQ to the basolateral side was <15% of that of Q, suggesting that prenylation attenuates transport from the intestine to the circulation. After intragastric administration of PQ or Q to mice or rats, the area under the concentration-time curve for PQ in plasma and lymph was 52.5% and 37.5% lower than that of Q, respectively. PQ and its O-methylated form (MePQ) accumulated at much higher amounts than Q and O-methylated Q in the liver (Q: 3400%; MePQ: 7570%) and kidney (Q: 385%; MePQ: 736%) of mice after 18 d of feeding. These data suggest that prenylation enhances the accumulation of Q in tissues during long-term feeding, even though prenylation per se lowers its intestinal absorption from the diet

Actin turnover maintains actin filament homeostasis during cytokinetic ring contraction

Cytokinesis in many eukaryotes involves a tension-generating actomyosin-based contractile ring. Many components of actomyosin rings turn over during contraction, although the significance of this turnover has remained enigmatic. Here, using Schizosaccharomyces japonicus, we investigate the role of turnover of actin and myosin II in its contraction. Actomyosin ring components self-organize into ∼1-µm-spaced clusters instead of undergoing full-ring contraction in the absence of continuous actin polymerization. This effect is reversed when actin filaments are stabilized. We tested the idea that the function of turnover is to ensure actin filament homeostasis in a synthetic system, in which we abolished turnover by fixing rings in cell ghosts with formaldehyde. We found that these rings contracted fully upon exogenous addition of a vertebrate myosin. We conclude that actin turnover is required to maintain actin filament homeostasis during ring contraction and that the requirement for turnover can be bypassed if homeostasis is achieved artificially

頚椎椎弓根スクリューの合併症と挿入精度に関する臨床的検討

金沢大学医学部附属病院リハビリテーション部Tomita, Katsuro学会抄