The geodynamic origin of Los Humeros volcanic field in Mexico: insights from numerical simulations.

Compared to normal arc-related volcanic eruptions, the formation of a volcanic caldera is a relatively atypical event. During caldera formation a series of large volumes of magma are erupted, reducing the structural support for the rock above the magma chamber and creating a large depression at the surface called caldera. Los Humeros volcanic field (LHVF) represents one of the largest volcanic calderas in Mexico. It is located some 400 km from the trench at the eastern edge of the Trans Mexican Volcanic Belt where the depth to the Cocos slab is more than 300 km. In this study we employ high-resolution two-dimensional thermomechanical numerical simulations of magma intrusions and a horizontal tectonic strain rate to better understand the influence of crustal deformation for the formation of Los Humeros caldera. A minimum number of three thermal anomaly pulses of hydrated mantle material (with diameter of 15 km or more) and a regional strain rate of 7.927 × 10-16 s-1 are required for magma to reach the surface. Modeling results show that regional extension coupled with deep thermal anomalies (with a temperature excess of ΔT ≥ 100 °C) that come in a specific chain-type sequence produce surface deformation patterns similar to LHVF. We propose an asthenospheric sub-slab deep source (> 300 km depth) for the thermal anomalies where previous studies showed the existence of a gap or tear in the Cocos slab.

Numerical modeling of subduction and evaluation of Philippine Sea Plate tectonic history along the Nankai Trough.

The subduction of the Philippine Sea (PHS) plate along the Nankai Trough in in southwest Japan is a relatively recent process compared with subduction along the Japan Trench in northeast Japan. However, the tectonic evolution of the PHS plate along the Nankai Trough is still controversial and not fully understood. There are several competing hypotheses based on different estimates for the time variations of convergence rate and plate age. Our study employs numerical modelling of subduction in order to evaluate the slab evolution for the last 15 Myr and aims to evaluate each tectonic scenario against the present-day slab geometry along a profile passing through the Shikoku and Chugoku regions. The modelling strategy involves a parameter study where subduction initiation and various subduction parameters are analyzed in terms of subduction geometry evolution. Two-dimensional visco-elasto-plastic numerical simulations of spontaneous bending subduction predict that convergence rate and plate age variations play an important role in the evolution of subduction geometry. Modeling results after 15 Myr of evolution reveal that the tectonic model based on a high convergence rate between ~ 15 Ma and ~ 3 Ma produces a slab geometry that agrees well with the observed present-day slab shape specific for the Shikoku and Chugoku regions.

A combination of subscapularis tendon transfer and small-head hemiarthroplasty for cuff tear arthropathy: a pilot study.

This pilot study reports the clinical outcomes of a combination of partial subscapularis tendon transfer and small-head hemiarthroplasty in patients with rotatator cuff arthropathy. A total of 30 patients (30 shoulders; eight men and 22 women) with a mean age of 74 years (55 to 84) were assessed at a mean follow-up of 31 months (24 to 60). The inclusion criteria were painful cuff tear arthropathy with normal deltoid function and a non-degenerative subscapularis muscle and tendon and a preserved teres minor. Outcome was assessed using the University of California Los Angeles score, the Japanese Orthopaedic Association score, and the Oxford Shoulder Score. Radiographic measurements included the centre of rotation distance and the length of the deltoid. All clinical scores were significantly improved post-operatively. The active flexion and external rotation improved significantly at the most recent follow-up (p < 0.035). Although the mean centre of rotation distance changed significantly (p < 0.001), the mean length of the deltoid did not change significantly from the pre-operative value (p = 0.29). The change in the length of the deltoid with < 100° flexion was significantly less than that with > 100° (p < 0.001). Progressive erosion of the glenoid was seen in four patients. No patient required revision or further surgery. A combination of partial subscapularis tendon transfer and small-head hemiarthroplasty effectively restored function and relieved pain in patients with rotator cuff arthropathy.

Triceps-sparing ulnar approach for total elbow arthroplasty.

To prevent insufficiency of the triceps after total elbow arthroplasty, we have, since 2008, used a triceps-sparing ulnar approach. This study evaluates the clinical results and post-operative alignment of the prosthesis using this approach. We reviewed 25 elbows in 23 patients. There were five men and 18 women with a mean age of 69 years (54 to 83). There were 18 elbows with rheumatoid arthritis, six with a fracture or pseudoarthrosis and one elbow with osteoarthritis. Post-operative complications included one intra-operative fracture, one elbow with heterotopic ossification, one transient ulnar nerve palsy, and one elbow with skin necrosis, but no elbow was affected by insufficiency of the triceps. Patients were followed for a mean of 42 months (24 to 77). The mean post-operative Japanese Orthopaedic Association Elbow Score was 90.8 (51 to 100) and the mean Mayo Elbow Performance score 93.8 (65 to 100). The mean post-operative flexion/extension of the elbow was 135°/-8°. The Manual Muscle Testing score of the triceps was 5 in 23 elbows and 2 in two elbows (one patient). The mean alignment of the implants examined by 3D-CT was 2.8° pronation (standard deviation (sd) 5.5), 0.3° valgus (sd 2.7), and 0.7° extension (sd 3.2) for the humeral component, and 9.3° pronation (sd 9.7), 0.3° valgus (sd 4.0), and 8.6° extension (sd 3.1) for the ulnar component. There was no radiolucent line or loosening of the implants on the final radiographs. The triceps-sparing ulnar approach allows satisfactory alignment of the implants, is effective in preventing post-operative triceps insufficiency, and gives satisfactory short-term results.

Radial osteotomy for late-stage Kienböck's disease. Wedge osteotomy versus radial shortening.

We have reviewed 20 patients with stage-IIIB and stage-IV Kienböck's disease in order to examine the efficacy of two forms of radial osteotomy, namely radial wedge osteotomy and radial shortening. Lateral closing wedge osteotomies and radial shortenings were carried out on 11 and nine patients, respectively. There were no preoperative differences with respect to age, gender, and radiological stage. After a mean follow-up of 29 months, all patients, in both groups, had either a good or an excellent outcome. After the lateral closing wedge osteotomy, the radioscaphoid angle significantly increased and the Ståhl index significantly decreased. Progression of the degenerative changes at the radioscaphoid joint was found in two patients in this group. By contrast, there were no significant changes in any radiological parameters after radial shortening. Both procedures gave acceptable clinical results in stage-IIIB and stage-IV Kienböck's disease.

Homophilic complex formation of MT1-MMP facilitates proMMP-2 activation on the cell surface and promotes tumor cell invasion.

Activation of proMMP-2 by MT1-MMP is considered to be a critical event in cancer cell invasion. In the activation step, TIMP-2 bound to MT1-MMP on the cell surface acts as a receptor for proMMP-2. Subsequently, adjacent TIMP-2-free MT1-MMP activates the proMMP-2 in the ternary complex. In this study, we demonstrate that MT1-MMP forms a homophilic complex through the hemopexin-like (PEX) domain that acts as a mechanism to keep MT1-MMP molecules close together to facilitate proMMP-2 activation. Deletion of the PEX domain in MT1-MMP, or swapping the domain with the one derived from MT4-MMP, abolished the ability to activate proMMP-2 on the cell surface without affecting the proteolytic activities. In addition, expression of the mutant MT1-MMP lacking the catalytic domain (MT1PEX-F) efficiently inhibited complex formation of the full-length enzymes and activation of pro MMP-2. Furthermore, expression of MT1PEX-F inhibited proMMP-2 activation and Matrigel invasion activity of invasive human fibrosarcoma HT1080 cells. These findings elucidate a new function of the PEX domain: regulating MT1-MMP activity on the cell surface, which accelerates cellular invasiveness in the tissue.

Thr226 is a key residue for bioluminescence spectra determination in beetle luciferases.

The comparison of click beetle and railroadworm luciferases (pH-insensitive) with firefly luciferases (pH-sensitive) showed a set of conserved residues differing between the two groups which could be involved with the bioluminescence spectra pH sensitivity. The substitution C258V in Pyrocoelia miyako (Pml) firefly luciferase and V255C in Ragophthalmus ohbai railroad worm luciferase (Rol) had no effect on the bioluminescence spectra. Substitution of Thr226 in the green-light-emitting luciferases of Rol and Pyrearinus termitilluminans (Pyt) click beetle luciferases resulted in red-shifts (12 to 35 nm), whereas the substitution T226N in the red-light-emitting luciferase of Phrixothrix hirtus (PhRE) railroadworm resulted in a 10 nm blue-shift. In PmL the substitution N230S resulted in a typical red mutant (lambda(max) = 611 nm). The bioluminescence spectrum of all these luciferase mutants did not show altered pH-sensitivity nor considerably changed half-bandwidth in relation to the wild-type luciferases. Altogether present data suggest that Thr226 is an important residue for keeping active-site core in both groups of beetle luciferases. The mechanism for bioluminescence color determination between pH-sensitive and pH-insensitive luciferases could be different.

Tonic descending facilitation from the rostral ventromedial medulla mediates opioid-induced abnormal pain and antinociceptive tolerance.

Many clinical case reports have suggested that sustained opioid exposure can elicit unexpected, paradoxical pain. Here, we explore the possibility that (1) opioid-induced pain results from tonic activation of descending pain facilitation arising in the rostral ventromedial medulla (RVM) and (2) the presence of such pain manifests behaviorally as antinociceptive tolerance. Rats implanted subcutaneously with pellets or osmotic minipumps delivering morphine displayed time-related tactile allodynia and thermal hyperalgesia (i. e., opioid-induced "pain"); placebo pellets or saline minipumps did not change thresholds. Opioid-induced pain was observed while morphine delivery continued and while the rats were not in withdrawal. RVM lidocaine, or bilateral lesions of the dorsolateral funiculus (DLF), did not change response thresholds in placebo-pelleted rats but blocked opioid-induced pain. The intrathecal morphine antinociceptive dose-response curve (DRC) in morphine-pelleted rats was displaced to the right of that in placebo-pelleted rats, indicating antinociceptive "tolerance." RVM lidocaine or bilateral DLF lesion did not alter the intrathecal morphine DRC in placebo-pelleted rats but blocked the rightward displacement seen in morphine-pelleted animals. The subcutaneous morphine antinociceptive DRC in morphine-pelleted rats was displaced to the right of that in placebo-pelleted rats; this right shift was blocked by RVM lidocaine. The data show that (1) opioids elicit pain through tonic activation of bulbospinal facilitation from the RVM, (2) increased pain decreases spinal opioid antinociceptive potency, and (3) blockade of pain restores antinociceptive potency, revealing no change in antinociceptive signal transduction. These studies offer a mechanism for paradoxical opioid-induced pain and allow the development of approaches by which the loss of analgesic activity of opioids might be inhibited.

Coracoacromial arch decompression in rotator cuff surgery.

In rotator cuff surgery it is important to obtain adequate decompression of the coracoacromial arch. However, it is difficult to localize the impingement site preoperatively. Based on histological and morphological studies and the clinical findings in 45 patients and 15 cadavers, we have tried to determine the impingement site. In addition, as a part of these investigations, we assessed the clinical outcome for 100 patients. Soft tissue decompression was indicated in 12 shoulders, anterior acromioplasty in 67 and anterior acromioplasty with coracoplasty in 21. According to Neer's criteria there were 92 satisfactory and 8 unsatisfactory results. The mean postoperative UCLA score was 33.4 points and the results were rated excellent in 78, good in 18 and fair in 4.

Postoperative subcoracoid impingement syndrome in patients with rotator cuff tear.

Impingement of the tendinous rotator cuff on the coracoid process (subcoracoid impingement syndrome) has rarely been reported as a cause of pain after surgery for rotator cuff tear. We evaluated clinical features, surgical results, and histopathology findings of resected coracoid processes in patients with subcoracoid impingement syndrome after anterior acromioplasty and management of rotator cuff tear. Pain at the anterior aspect of the shoulder, localized tenderness of the coracoid process, anterior shoulder pain on horizontal adduction testing, and positive subcoracoid block suggest subcoracoid impingement syndrome. Postoperative subcoracoid impingement syndrome was investigated in 11 of 216 cases with rotator cuff surgery. The average patient age at the time of surgery was 61.2 y (range, 28-78 y). Coracoplasty (partial resection of the posterolateral side of the coracoid process) was performed in 9 shoulders that had not responded to a 6-month regimen of conservative treatment. Complete pain relief was achieved in all cases. Histopathologic findings revealed hypertrophic changes of the fibrocartilage layer at the posterior aspect of the resected coracoid process. We concluded that subcoracoid impingement syndrome was an important factor in unsuccessful rotator cuff surgery and recommend that coracoplasty be performed on patients with symptoms of subcoracoid impingement syndrome after management of the rotator cuff tear.

Distally-based free vascularized tissue grafts in the lower leg.

In the field of orthopaedic surgery, the lower leg is often treated by free vascularized tissue grafts. In performing these grafts for reconstruction of the lower leg, the anterior tibial artery and its venae comitantes are frequently selected as anastomosing recipient vessels. However, due to the deep location of the anterior tibial vessels, it is extremely difficult to accomplish antegrade microsurgical anastomoses between the donor vessels and the anterior tibial vessels. This technical difficulty often leads to the possibility of immediate postoperative arterial and venous occlusion. To resolve this problem, the idea of a reverse-flow island flap has been applied to the free vascularized tissue grafts for reconstruction of the lower leg, based on both artery and vein reconstructed with retrograde blood flow. To evaluate clinical outcomes of the procedure mentioned, the postoperative results of 14 patients were reviewed. The free vascularized grafts consisted of seven vascularized fibular grafts with peroneal flaps, six vascularized latissimus dorsi myocutaneous flaps, and one vascularized groin flap. Venous congestion of the flap was not observed and all flaps survived. Bone union was obtained in seven patients treated with vascularized fibular grafts. There were no serious postoperative complications. Distally-based free vascularized tissue grafts in the lower leg are useful procedures in reconstruction of massive bone defects and osteomyelitis of the tibia, and for skin defects on the anterior aspect of the lower leg.

Long-term results of multiple muscle transfer to reconstruct shoulder function in patients with birth palsy: eleven-year follow-up.

We evaluated the long-term clinical results of multiple muscle transfer for reconstruction of shoulder function in 10 patients with birth palsy. Multiple muscle transfer consists mainly of Harmon's deltoid shift, Ober's biceps muscle transfer, and Hoffer's latissimus dorsi muscle transfer. The follow-up ranged from 5 to 14 years with an average of 10.5 years. Two of the 10 patients showed no improvement, one due to severely atrophied latissimus dorsi muscle, and the other who had not received Hoffer's latissimus dorsi muscle transfer. Except for these two patients, an averaged flexion and external angles were 114 degrees and 25 degrees, respectively. Harmon's deltoid shift and Hoffer's latissimus dorsi muscle transfer for reconstruction of shoulder function in patients with birth palsy have proven to be a useful method in reconstructing and maintaining the function of active elevation and external rotation of the shoulder.

Electromyographic study during isometric exercise of the shoulder in head-out water immersion.

Water exercises are used for early rehabilitation programs after shoulder injury such as rotator cuff tear, yet no literature discusses the muscle activity of such rehabilitation programs in water. The purpose of this study was to analyze the electromyographic activity from 8 volunteers during isometric exercises in water and on land. Nine isometric exercises were studied: with 30 degrees, 60 degrees, and 90 degrees shoulder flexion and abduction, and 3 positions of shoulder rotation at 0 degrees abduction (both maximal internal and external rotation and mid-position). Nine parts of 6 muscles were studied: the supraspinatus, infraspinatus, subscapularis, 2 parts of the pectoralis major (clavicular and costal), 3 parts of the deltoid (anterior, middle, and posterior), and the latissimus dorsi. The electromyographic signals were low-pass filtered, full-wave rectified, and integrated for 5 seconds. The electromyographic activity was quantified as a percentage of the maximal manual muscle test. The results showed that supraspinatus activity at 90 degrees abduction significantly decreased from 22.3+/-15.8 on land to 3.9+/-3.3% manual muscle test in water (P < .01). Other muscle activities in water also decreased remarkably compared with those on land. These results provide valuable information for the safety of water exercise for early rehabilitation programs after shoulder injury such as rotator cuff tear.

[Clinical study of MRSA carrier in sputum].

We studied the clinical aspects of 25 patients (17 male, 8 female, median age 79.4 y.o.) whom MRSA was colonized in sputum from 1989 January to 1994 December. Main underlying diseases were 16 chronic bronchitis and 15 Cerebrovascular damage. Nineteen cases (76%) had catheters, for example 15 urinary tract catheters and 8 nasogastric tube. Twenty-two cases (88%) used previous antimicrobial agent. Fifteen cases (60%) were dead during previous period, and that 14 cases were dead because of respiratory failure within a year after MRSA was colonized in sputum. Nine cases (36%) were able to remove MRSA in sputum, but mortality rate was not different whether MRSA disappear or continue, MIC50 against MRSA (19 strains) were minocycline 12.5 micrograms/ml, arbekacin 6.25 micrograms/ml, vancomycin 0.78 microgram/ml and 16 cases (84.2%) were coagulase type II.

Effect of caffeine on the mental calculation.

The double blind study of the effect of caffeine on the mental calculation has been carried out every year in the undergraduate course of Clinical Pharmacology, Medical School, Kyushu University. The results obtained from 1980 to 1996 are summarized and evaluated.

[Clinical study of 18 patients whom MRSA was detected from stool--especially about comparison enterocolitis with colonization].

We studied the clinical aspects of 18 patients from whom MRSA was detected from the stool and compared with 9 enterocolitis cases (7 male, 2 female, median age 72.4 y.o.) with 9 colonization cases (5 male, 4 female, median age 70.2 y.o.) from 1991 June to 1995 May. Cases of postoperative, use of anti-peptic ulcer drugs and administration of antibiotics for enterocolitis were more than that of colonization. On the other hand, eatable patients in the colonization group who could take food orally were more in number. Many patients of both enterocolitis and colonization were colonized in the respiratory tract. Drug sensitivity of MRSA in both cases were almost the same and the coagulase type were all that of II. Three courses on how MRSA enterocolitis occurs is considered. At first, colonization in the respiratory tract, second, proliferation of MRSA in the higher pH gastric juices as a result of gastrectomy or use of anti-peptic ulcer drugs, and third, selection of MRSA after administration of antibiotics.

Clinical results of treatment of triangular fibrocartilage complex tears by arthroscopic debridement.

In order to determine indications for arthroscopic debridement and the management of triangular fibrocartilage complex (TFCC) tears, we reviewed 16 wrists retrospectively. The mean patient age was 30 years, with a range of 20 to 53 years. The follow-up period averaged 35 months. Two groups were identified: post-traumatic tears (n = 11) and degenerative tears (n = 5). The results of arthroscopic debridement were compared and analyzed based on the preoperative and postoperative evaluation of pain, range of motion, grip strength, return to work, patient acceptance, and complications. Failures were further evaluated to determine identifiable lesions or anatomic defects associated with poor results. Patients with positive ulnar variance and lunotriquentral interosseous ligament tears had a poor clinical outcome. Good results correlated with grip strength; all patients with post-traumatic TFCC tears had excellent results, while those with degenerative TFCC tears did poorly.

The Sauvé-Kapandji procedure for osteoarthritis of the distal radioulnar joint.

The Sauvé-Kapandji procedure has been performed in 15 patients with primary and secondary osteoarthritis of the distal radioulnar joint. The average age of the patients was 45 years (range, 31-63 years). There were 12 men and 3 women. The follow-up period averaged 2 years and 11 months. Postoperative pain relief was good in all wrists. The preoperative range of motion of the wrist joint averaged 50 degrees extension and 44 degrees flexion. Forearm motion averaged 66 degrees pronation and 64 degrees supination. Postoperatively, the range of motion improved to 55 degrees extension and 51 degrees flexion at the wrist and forearm motion improved to 78 degrees pronation and 82 degrees supination. Although all wrists also showed an increased grip strength and improved range of motion over preoperative values, these did not have statistical significance. Postoperative x-ray evaluation showed an unstable proximal stump and radioulnar convergence in 12 wrists. Our clinical and x-ray film findings suggest that the Sauvé-Kapandji procedure is a satisfactory procedure for patients with osteoarthritis of the distal radioulnar joint.

Degradation of humoral host defense by Candida albicans proteinase.

The effect of an extracellular proteinase from the pathogenic yeast Candida albicans on the bactericidal and opsonizing activities of human serum was studied. The ability of human polymorphonuclear leukocytes to kill Staphylococcus aureus was greatly reduced when the bacteria were opsonized with human serum treated with the proteinase. The reduction in the opsonizing activity of human serum was attributed to degradation of the Fc portion of immunoglobulin G by the action of C. albicans proteinase as determined by immunoprecipitation reaction. However, the Fab portion of immunoglobulin G was resistant to proteolysis by the proteinase. A clear reduction in the bactericidal activity of human serum against Escherichia coli was observed when the serum was treated with C. albicans proteinase. The reduction of serum bactericidal activity was attributed to the degradation of complement C3 by proteolysis by the proteinase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while C5 resisted the action of the proteinase. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the proteinase also degrades endogenous proteinase inhibitors, such as alpha 2 macroglobulin and alpha 1 proteinase inhibitor, which are involved in regulating inflammation. These results suggest that destruction of a host's defense-oriented or regulatory proteins facilitates debilitation of the infected host.