Open Foveal Repair of the Triangular Fibrocartilage Complex Tears Associated with Symptomatic Ulnar Styloid Non-union.

Background: Symptomatic ulnar styloid non-union can be treated by excision of the ulnar styloid fragment. For combined triangular fibrocartilage complex (TFCC) tears, several repair techniques such as arthroscopic repair, open repair to the fracture site or reconstruction using a tendon graft have been introduced. This study reports the technique and outcomes of open foveal repair of the TFCC with excision of the ulnar styloid fragment in patients with symptomatic ulnar styloid non-union and distal radioulnar joint (DRUJ) instability. Methods: Consecutive patients with symptomatic ulnar styloid non-union with TFCC tears and DRUJ instability who underwent excision of the ulnar styloid fragment and open foveal repair of the TFCC were retrospectively reviewed. After excising the ulnar styloid fragment, a capsular window was created between the triquetrum and TFCC, followed by attaching the TFCC to the fovea using three sutures through a bone tunnel from the ulnar cortex to the fovea. Additional ulnar shortening osteotomies were performed in patients with positive ulnar variance and ulnar impaction test. The outcomes were evaluated in terms of DRUJ stability and the Quick Disabilities of the Arm, Shoulder and Hand (DASH) scores. Results: In total, 21 patients with a mean age of 40 were enrolled in the study. All patients demonstrated DRUJ stability at a mean follow-up duration of 14 months. The mean Quick DASH score significantly improved from 18.9 ± 11.7 to 2.5 ± 4.1 (p < 0.05). Eleven patients underwent combined ulnar shortening osteotomies, and no difference in the Quick DASH score was found between patients who underwent ulnar shortening osteotomy and those who did not. Conclusions: This study demonstrates that open foveal repair of the TFCC with ulnar styloid fragment excision is an effective strategy to surgically treat patients with symptomatic ulnar styloid non-union with TFCC tear and DRUJ instability. Level of Evidence: Level III (Therapeutic).

Fast skeletal myosin-binding protein-C regulates fast skeletal muscle contraction.

Fast skeletal myosin-binding protein-C (fMyBP-C) is one of three MyBP-C paralogs and is predominantly expressed in fast skeletal muscle. Mutations in the gene that encodes fMyBP-C, MYBPC2, are associated with distal arthrogryposis, while loss of fMyBP-C protein is associated with diseased muscle. However, the functional and structural roles of fMyBP-C in skeletal muscle remain unclear. To address this gap, we generated a homozygous fMyBP-C knockout mouse (C2-/-) and characterized it both in vivo and in vitro compared to wild-type mice. Ablation of fMyBP-C was benign in terms of muscle weight, fiber type, cross-sectional area, and sarcomere ultrastructure. However, grip strength and plantar flexor muscle strength were significantly decreased in C2-/- mice. Peak isometric tetanic force and isotonic speed of contraction were significantly reduced in isolated extensor digitorum longus (EDL) from C2-/- mice. Small-angle X-ray diffraction of C2-/- EDL muscle showed significantly increased equatorial intensity ratio during contraction, indicating a greater shift of myosin heads toward actin, while MLL4 layer line intensity was decreased at rest, indicating less ordered myosin heads. Interfilament lattice spacing increased significantly in C2-/- EDL muscle. Consistent with these findings, we observed a significant reduction of steady-state isometric force during Ca2+-activation, decreased myofilament calcium sensitivity, and sinusoidal stiffness in skinned EDL muscle fibers from C2-/- mice. Finally, C2-/- muscles displayed disruption of inflammatory and regenerative pathways, along with increased muscle damage upon mechanical overload. Together, our data suggest that fMyBP-C is essential for maximal speed and force of contraction, sarcomere integrity, and calcium sensitivity in fast-twitch muscle.

Postoperative Intravenous Iron Supplementation Does Not Improve Hemoglobin Level and Transfusion Rate Following Staged Bilateral Total Knee Arthroplasty.

BACKGROUND: We determined whether postoperative intravenous (IV) iron supplementation could reduce transfusion rate in patients undergoing staged bilateral total knee arthroplasty (TKA). Furthermore, we examined whether hemoglobin (Hb) levels and iron profile differed between patients with and without postoperative IV iron supplementation. METHODS: This retrospective, comparative cohort study included 126 patients who underwent primary staged bilateral TKA during a single hospitalization. The second TKA was performed at a week's interval. Group iron (n = 65) received IV iron immediately after each surgery, while patients in group no-iron (n = 61) received no iron after surgery. Transfusion rate, change in Hb levels, and iron profile including serum iron, ferritin, total iron binding capacity, and transferrin saturation were evaluated preoperatively; on postoperative days 1, 2, and 4 after the first TKA; and postoperative days 1, 2, 4, and 7, 6 weeks, and 3 months after the second TKA. RESULTS: There were no significant differences in Hb levels and transfusion rate following staged bilateral TKA between patients with and without postoperative IV iron supplementation although serum iron profiles were improved in patients with IV iron supplementation. CONCLUSION: Postoperative IV iron supplementation immediately after acute blood loss caused by TKA was not effective in improving the transfusion rate. Therefore, surgeons should use protocols other than postoperative IV iron supplementation for reducing the transfusion rate in patients undergoing staged bilateral TKA in a single hospitalization. LEVEL OF EVIDENCE: III.

Is Thumb Proprioception Decreased in Patients With Trapeziometacarpal Joint Osteoarthritis?

Proprioception is thought to be essential for normal joint homeostasis, and its decreased function has been associated with an increased risk of joint diseases. However, only a few studies have been performed on the association between proprioceptive function in the trapeziometacarpal joint (TMCJ) and osteoarthritis. The purpose of this study was to compare TMCJ proprioceptive function in elderly women with radiographic TMCJ osteoarthritis relative to age-matched control women without osteoarthritis. We enrolled 19 women (mean age, 66 years) with symptomatic, radiographic Eaton and Littler grade 2, 3, and 4 TMCJ osteoarthritis and 19 age-matched control women without osteoarthritis. We evaluated thumb proprioception by using a joint-position reproduction test and compared the reposition error (RE) between the groups. We carried out a multivariate analysis for factors potentially associated with increased RE, such as age, body mass index, hand dominance, the presence of diabetes, pain level, and the presence of osteoarthritis. Also, a logistic regression analysis was performed for factors associated with the occurrence of TMCJ osteoarthritis. Patients with TMCJ osteoarthritis had greater RE than did the control patients in the joint-position reproduction test at 20°, 30°, and 40° of thumb palmar abduction. The multivariate analysis indicated that increased RE was associated with the presence of osteoarthritis, but not with the other factors assessed. The occurrence of TMCJ osteoarthritis was associated with increased RE at 20°, 30°, and 40° of thumb palmar abduction. This study showed that decreased proprioceptive function was associated with the presence of osteoarthritis in the TMCJ, although the causality remains unknown. Further studies on the role of proprioception in the pathogenesis of TMCJ osteoarthritis and the potential role of its training for disease prevention or treatment are required.

The myosin interacting-heads motif present in live tarantula muscle explains tetanic and posttetanic phosphorylation mechanisms.

Striated muscle contraction involves sliding of actin thin filaments along myosin thick filaments, controlled by calcium through thin filament activation. In relaxed muscle, the two heads of myosin interact with each other on the filament surface to form the interacting-heads motif (IHM). A key question is how both heads are released from the surface to approach actin and produce force. We used time-resolved synchrotron X-ray diffraction to study tarantula muscle before and after tetani. The patterns showed that the IHM is present in live relaxed muscle. Tetanic contraction produced only a very small backbone elongation, implying that mechanosensing-proposed in vertebrate muscle-is not of primary importance in tarantula. Rather, thick filament activation results from increases in myosin phosphorylation that release a fraction of heads to produce force, with the remainder staying in the ordered IHM configuration. After the tetanus, the released heads slowly recover toward the resting, helically ordered state. During this time the released heads remain close to actin and can quickly rebind, enhancing the force produced by posttetanic twitches, structurally explaining posttetanic potentiation. Taken together, these results suggest that, in addition to stretch activation in insects, two other mechanisms for thick filament activation have evolved to disrupt the interactions that establish the relaxed helices of IHMs: one in invertebrates, by either regulatory light-chain phosphorylation (as in arthropods) or Ca2+-binding (in mollusks, lacking phosphorylation), and another in vertebrates, by mechanosensing.

A retrospective comparative study of infection control rate and clinical outcome between open debridement using antibiotic-impregnated cement beads and a two-stage revision in acute periprosthetic knee joint infection.

The aim of this study was to determine whether the infection control rate of a modified debridement, antibiotics, and implant retention (DAIR) protocol (DAIR with antibiotic-impregnated cement beads) is comparable to that of 2-stage revision for acute periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). We also aimed to determine whether this modified DAIR technique produced better clinical results than those obtained using 2-stage revision in terms of functional outcome, range of motion (ROM), and patient satisfaction at 2 years after surgery.This retrospective comparative study included patients who underwent modified DAIR (7 patients, 9 knees) or 2-stage revision (8 patients, 9 knees) for acute PJI of the knee joint. Infection control rate, functional outcome measured using Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, ROM and patient satisfaction were compared between the two groups.There was no difference in infection control rates between the modified DAIR and 2-stage revision groups (78% vs 78%, respectively). In contrast, surgical outcome in the modified DAIR group was tended to be better than 2-stage revision group, but it did not reach statistical significance. Median maximal range of flexion was 103° in the modified DAIR group and it was 90° in the 2-stage group (P = .191). In addition, the median WOMAC function score was 24 in the modified DAIR group and it was 30 in the 2-stage group (P = .076). Median patient satisfaction measured using visual analogue scale was 8 in the modified DAIR group and 5 in the 2-stage group (P = .069).The infection control rates of the modified DAIR protocol and 2-stage revision protocol were similar for the treatment of acute PJI of the knee joint. However, the modified DAIR protocol could not provide substantially increased functional outcomes and patient satisfaction compared to 2-stage revision. Therefore, the modified DAIR technique should be considered to be of limited use in patients with high surgical morbidity.

Different Strategies in Making Transseptal Portal for the Different Purposes.

The purpose of this study was to find the most suitable and safe position of the transseptal portal in anatomic anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstructions. The hypothesis of this study was that area and position of the transseptal portal are different between ACL and PCL reconstructions for the observation of native footprint. A matched-pair comparison study was conducted on the arthroscopic images of 100 consecutive patients who underwent ACL reconstruction and 50 consecutive patients who underwent PCL reconstruction. The transseptum was divided into six compartments. The opened compartments for each surgery were then evaluated to find which anatomical structures are well seen. The anterior middle and upper parts were necessary for the ACL reconstruction, whereas middle and lower portions of the anterior and posterior compartments were necessary for the PCL reconstruction. A larger opening was necessary for PCL reconstruction than that for ACL reconstruction. The ACL posterior one-third, ACL femoral attachment, and apex of the deep cartilage margin (DCM) were viewed in 100% of the patients during ACL reconstruction. The PCL posterior one-third, PCL tibial attachment, PCL fovea margin, and medial meniscus around posterior margin were always viewed during PCL reconstruction. The anterior part of the septum, from the middle to the upper portions of the transseptum, was necessary to be opened for visualization of the femoral footprint and DCM of the lateral femoral condyle during ACL reconstruction. The anterior and posterior parts of the septum, from the middle to the lower portions of the transseptum, were necessary for excellent visualization of the PCL tibial footprint during PCL reconstruction. These paths of the transseptal portal for each surgery will help surgeons obtain both anatomic footprint restoration and maximal remnant preservation through the most suitable and safe means. This is a case-control study; level of evidence is 3.

Lattice arrangement of myosin filaments correlates with fiber type in rat skeletal muscle.

The thick (myosin-containing) filaments of vertebrate skeletal muscle are arranged in a hexagonal lattice, interleaved with an array of thin (actin-containing) filaments with which they interact to produce contraction. X-ray diffraction and EM have shown that there are two types of thick filament lattice. In the simple lattice, all filaments have the same orientation about their long axis, while in the superlattice, nearest neighbors have rotations differing by 0° or 60°. Tetrapods (amphibians, reptiles, birds, and mammals) typically have only a superlattice, while the simple lattice is confined to fish. We have performed x-ray diffraction and electron microscopy of the soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat and found that while the EDL has a superlattice as expected, the SOL has a simple lattice. The EDL and SOL of the rat are unusual in being essentially pure fast and slow muscles, respectively. The mixed fiber content of most tetrapod muscles and/or lattice disorder may explain why the simple lattice has not been apparent in these vertebrates before. This is supported by only weak simple lattice diffraction in the x-ray pattern of mouse SOL, which has a greater mix of fiber types than rat SOL. We conclude that the simple lattice might be common in tetrapods. The correlation between fiber type and filament lattice arrangement suggests that the lattice arrangement may contribute to the functional properties of a muscle.

Altered C10 domain in cardiac myosin binding protein-C results in hypertrophic cardiomyopathy.

AIMS: A 25-base pair deletion in the cardiac myosin binding protein-C (cMyBP-C) gene (MYBPC3), proposed to skip exon 33, modifies the C10 domain (cMyBP-CΔC10mut) and is associated with hypertrophic cardiomyopathy (HCM) and heart failure, affecting approximately 100 million South Asians. However, the molecular mechanisms underlying the pathogenicity of cMyBP-CΔC10mutin vivo are unknown. We hypothesized that expression of cMyBP-CΔC10mut exerts a poison polypeptide effect leading to improper assembly of cardiac sarcomeres and the development of HCM. METHODS AND RESULTS: To determine whether expression of cMyBP-CΔC10mut is sufficient to cause HCM and contractile dysfunction in vivo, we generated transgenic (TG) mice having cardiac-specific protein expression of cMyBP-CΔC10mut at approximately half the level of endogenous cMyBP-C. At 12 weeks of age, significant hypertrophy was observed in TG mice expressing cMyBP-CΔC10mut (heart weight/body weight ratio: 4.43 ± 0.11 mg/g non-transgenic (NTG) vs. 5.34 ± 0.25 mg/g cMyBP-CΔC10mut, P < 0.05). Furthermore, haematoxylin and eosin, Masson's trichrome staining, as well as second-harmonic generation imaging revealed the presence of significant fibrosis and a greater relative nuclear area in cMyBP-CΔC10mut hearts compared with NTG controls. M-mode echocardiography analysis revealed hypercontractile hearts (EF: 53.4%±2.9% NTG vs. 66.4% ± 4.7% cMyBP-CΔC10mut; P < 0.05) and early diastolic dysfunction (E/E': 28.7 ± 3.7 NTG vs. 46.3 ± 8.4 cMyBP-CΔC10mut; P < 0.05), indicating the presence of an HCM phenotype. To assess whether these changes manifested at the myofilament level, contractile function of single skinned cardiomyocytes was measured. Preserved maximum force generation and increased Ca2+-sensitivity of force generation were observed in cardiomyocytes from cMyBP-CΔC10mut mice compared with NTG controls (EC50: 3.6 ± 0.02 µM NTG vs. 2.90 ± 0.01 µM cMyBP-CΔC10mut; P < 0.0001). CONCLUSION: Expression of cMyBP-C protein with a modified C10 domain is sufficient to cause contractile dysfunction and HCM in vivo.

Effects of lifetime cumulative ginseng intake on cognitive function in late life.

BACKGROUND: We investigated the effects of lifetime cumulative ginseng intake on cognitive function in a community-dwelling population-based prospective cohort of Korean elders. METHODS: Community-dwelling elders (N = 6422; mean age = 70.2 ± 6.9 years, education = 8.0 ± 5.3 years, female = 56.8%) from the Korean Longitudinal Study on Cognitive Aging and Dementia were included. Among them, 3918 participants (61.0%) completed the 2-year and 4-year follow-up evaluations. Subjects were categorized according to cumulative ginseng intake at baseline evaluation; no use group, low use (< 5 years) group, and high use (≥ 5 years) group. One-way analysis of covariance (ANCOVA) was conducted to compare the impact of cumulative ginseng intake on baseline Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet neuropsychological battery total score (CERAD total score) and Mini-Mental State Examination (MMSE) score among the three groups while adjusting for potential covariates. A repeated-measures ANCOVA was performed to investigate the impacts on the changes in CERAD total scores and MMSE scores during the 4 years of follow-up. RESULTS: The high use group showed higher CERAD total scores compared to the no use group after controlling for age, sex, education years, socioeconomic status, smoking, alcohol intake, presence of hypertension, stroke history, Geriatric Depression Scale, Cumulative Illness Rating Scale, and presence of the APOE e4 allele (F(2, 4762) = 3.978, p = 0.019). The changes of CERAD total score for 2 or 4 years of follow-up did not differ according to the use of ginseng. CONCLUSIONS: Cumulative ginseng use for longer than 5 years may be beneficial to cognitive function in late life.

Interacting-heads motif has been conserved as a mechanism of myosin II inhibition since before the origin of animals.

Electron microscope studies have shown that the switched-off state of myosin II in muscle involves intramolecular interaction between the two heads of myosin and between one head and the tail. The interaction, seen in both myosin filaments and isolated molecules, inhibits activity by blocking actin-binding and ATPase sites on myosin. This interacting-heads motif is highly conserved, occurring in invertebrates and vertebrates, in striated, smooth, and nonmuscle myosin IIs, and in myosins regulated by both Ca2+ binding and regulatory light-chain phosphorylation. Our goal was to determine how early this motif arose by studying the structure of inhibited myosin II molecules from primitive animals and from earlier, unicellular species that predate animals. Myosin II from Cnidaria (sea anemones, jellyfish), the most primitive animals with muscles, and Porifera (sponges), the most primitive of all animals (lacking muscle tissue) showed the same interacting-heads structure as myosins from higher animals, confirming the early origin of the motif. The social amoeba Dictyostelium discoideum showed a similar, but modified, version of the motif, while the amoeba Acanthamoeba castellanii and fission yeast (Schizosaccharomyces pombe) showed no head-head interaction, consistent with the different sequences and regulatory mechanisms of these myosins compared with animal myosin IIs. Our results suggest that head-head/head-tail interactions have been conserved, with slight modifications, as a mechanism for regulating myosin II activity from the emergence of the first animals and before. The early origins of these interactions highlight their importance in generating the inhibited (relaxed) state of myosin in muscle and nonmuscle cells.

Diagnosis of Churg-Strauss Syndrome Presented With Neuroendocrine Carcinoma: A Case Report.

Churg-Strauss syndrome (CSS) is a rare systemic vasculitis that affect small and medium-sized blood vessels and is accompanied by asthma, eosinophilia, and peripheral neuropathy. This report describes a case of a 52-year-old man who had a history of sinusitis, asthma, and thymus cancer and who had complained of bilateral lower extremity paresthesia and weakness for a month. Peripheral neuropathy was detected by electrodiagnostic studies. Resection of a mediastinal mass, which was diagnosed as thymic neuroendocrine carcinoma, was performed five months before his visit. After thymectomy, peripheral blood tests revealed a gradual increase in eosinophils. Two months after surgery, he was admitted to the hospital for dyspnea, and nodules of focal consolidation were found in his chest X-ray. One month later, pyoderma occurred in the right shin, and the skin biopsy showed extravascular eosinophilic infiltration. He was diagnosed with CSS after thymectomy, and we report a very rare case of CSS presented with thymic neuroendocrine carcinoma.

Dispersion and reaggregation of nanoparticles in the polypropylene copolymer foamed by supercritical carbon dioxide.

For the preparation of nanocomposites, we conducted environmentally benign foaming processing on polypropylene (PP) copolymer/clay nanocomposites via a batch process in an autoclave. We investigated the dispersion and the exfoliation of the nanoclay particles. Full exfoliation was achieved by the foamability of the matrix PP copolymer using supercritical carbon dioxide (sc CO2) and subcritical carbon dioxide (sub CO2). More and smaller cells were observed when the clay was blended as heterogeneous nuclei and sc CO2 was used. Small angle X-ray scattering showed that highly dispersed states (exfoliation) of the clay particles were obtained by the foaming process. Since the clay particles provided more nucleating sites for the foaming of the polymer, a well dispersed (or fully exfoliated) nanocomposite exhibited a higher cell density and a smaller cell size at the same clay particle concentration. Expansion of the adsorbed CO2 facilitated the exfoliation of the clay platelets; thus, sc CO2 at lower temperature was more efficient for uniform foaming-cell production. Fully dispersed clay platelets were, however, re-aggregated when subjected to a further melting processing. The reprocessed nanocomposites still had some exfoliated platelets as well as some aggregated intercalates. The dual role of the nanoclay particles as foaming nucleus and a crystallization nucleus was confirmed by cell growth observation and nonisothermal crystallization kinetics analysis. A low foaming temperature and a high saturation pressure were more favorable for obtaining a uniform foam. The PP copolymer was found to be foamed more easily than polypropylene. A small amount of other olefin moieties in the backbone of the polymer facilitated better foamability than the neat polypropylene.

Acute respiratory failure associated with cryptococcal pneumonia and disseminated cryptococcosis in an AIDS patient.

A 36-year-old homosexual Mexican man was admitted to our hospital, with a 30-day history of fever and headache. Upon cerebrospinal fluid examination, the patient's white blood cell count was 1,580/L, total protein was 26 mg/dL, sugar was 17 mg/dL, and his intracranial pressure was 23 cmH2O. The patient was diagnosed with HIV (Human Immunodeficiency Virus) infection by serum Western blotting. Cryptococcus neoformans was isolated in cultures of the patient's blood and cerebrospinal fluids. Chest computerized tomography revealed diffuse reticulonodular infiltration and a ground-glass appearance in both perihilar regions, suggestive of either Pneumocystis carinii pneumonia or cryptococcal pneumonia. On the patient's 6th day in our hospital, bronchoalveolar lavage and transbronchial lung biopsy were conducted via bronchoscopy, and a pathologic examination of lung biopsy specimens revealed signs of cryptococcal pneumonia. This patient died on his 14th day in our hospital, as the result of acute respiratory failure, associated with cryptococcal pneumonia and disseminated cryptococcosis.

Hypersensitivity reactions to oxaliplatin.

Oxaliplatin is a third-generation platinum compound that is used as a single agent and in combination with fluorouracil (5-FU) to treat colorectal and gastric carcinoma. The patients treated with oxaliplatin may develop hypersensitivity and idiosyncratic reactions, although these complications are known to be rare. We report here on two patients who suffered with metastatic colorectal cancer and who underwent palliative combination chemotherapy with oxaliplatin; they then developed hypersensitivity reactions to oxaliplatin. The first case had an anaphylatic reaction immediately after the beginning of the 7(th) to 8(th) cycle infusion of oxaliplatin. The second case developed repeated febrile episodes from the 4(th) to 8(th) cycles of oxaliplatin infusion. With the increasing use of oxaliplatin in clinical practice, we are now encountering an increasing incidence of suspected hypersensitivity reactions. Physicians should keep their eyes wide open and carefully observe for the clinical manifestations of these hypersensitivity reactions.