Enhanced North Pacific deep-ocean stratification by stronger intermediate water formation during Heinrich Stadial 1.

The deglacial history of CO2 release from the deep North Pacific remains unresolved. This is due to conflicting indications about subarctic Pacific ventilation changes based on various marine proxies, especially for Heinrich Stadial 1 (HS-1) when a rapid atmospheric CO2 rise occurs. Here, we use a complex Earth System Model to investigate the deglacial North Pacific overturning and its control on ocean stratification. Our results show an enhanced intermediate-to-deep ocean stratification coeval with intensified North Pacific Intermediate Water (NPIW) formation during HS-1, compared to the Last Glacial Maximum. The stronger NPIW formation causes lower salinities and higher temperatures at intermediate depths. By lowering NPIW densities, this enlarges vertical density gradient and thus enhances intermediate-to-deep ocean stratification during HS-1. Physically, this process prevents the North Pacific deep waters from a better communication with the upper oceans, thus prolongs the existing isolation of glacial Pacific abyssal carbons during HS-1.

Knee osteochondral fractures in skeletally immature patients: French multicenter study.

INTRODUCTION: Femoral or patellar osteochondral fractures complicating patellar dislocation are more frequently observed in adolescents than in adults. These incidental lesions of vulnerable joint cartilage are often neglected in the initial phase, which is regrettable given their good capacity for healing after repositioning. The objective of this study was to investigate the characteristics and analyze the results of repositioning these fractures in skeletally immature patients. MATERIAL AND METHODS: This retrospective multicenter study grouped 14 patients and knees (seven females). The mean age at the time of the accident was 12.9 years (range, 11.2-14.9 years) for the girls and 14 years (range, 12.2-15 years) for the boys. These fractures involved the lateral condyle in nine cases and the patella in five cases. The injury mechanism was secondary to demonstrated patellar dislocation (n=9) or a direct impact (n=4). In nine cases out of 14, a leisure sports accident was the cause. The injury was treated a mean 5.2 days (range, 0-20 days) after the accident. All of the detached fragments were repositioned surgically with screw fixation (n=5), resorbable pins (n=5), or pull-out suture (n=4). Biological glue was added for six patients. Patellar stabilization was associated during the same procedure in two cases. RESULTS: No postoperative complications were observed. The results at the mean follow-up of 30 months (range, 15-89 months) showed no revision for failure, with all of the fractures demonstrating union at the final examination. The mean IKDC 2000 subjective score was 88±6 (range, 79-98) out of 100 points. The subjective satisfaction level was very satisfied in two cases and satisfied in the 12 others. The final IKDC score was A for eight patients, B for five patients, and C for one patient. Three patients underwent secondary patellar stabilization surgery. CONCLUSION: Better knowledge of this fracture and attentive reading of the radiographic images of a knee with hemarthrosis should result in more frequent diagnosis of this condition and adapted treatment. Unexplained hemarthrosis in a context of trochlear dysplasia should be considered to be associated with an OCF until proof of the contrary. A fragment released in a weightbearing zone should ideally be repositioned within 10 days but remains possible at 2 months. It regularly provides bone union and good results in children.

Type IV-D thumb duplication: A new reconstruction method.

INTRODUCTION: In the Wassel type IV classification category, the thumb is duplicated from the metacarpophalangeal joint; this abnormality accounts for approximately 50% of the cases of thumb duplication. Type IV is divided into four subtypes in which the IV-D type, or convergent (9% of cases), is the most complex form because both thumbs are hypoplastic with a divergent metacarpophalangeal joint and a convergent interphalangeal joint. Reconstruction is prone to axis deformity and ligament laxity, whereas the Bilhaut-Cloquet technique's main pitfall is nail dystrophy. We propose a modified Bilhaut-Cloquet procedure to avoid these complications. MATERIAL AND METHOD: Four males (mean age: 11 months; range: 10-12 months) with IV-D thumb duplication were operated on using a modified Bilhaut-Cloquet procedure. SURGICAL TECHNIQUE: The skin is preliminarily marked, taking into account the excision of the central skin and the more hypoplastic nail of the two (most often the radial nail). Both proximal phalanges are split longitudinally and the central halves discarded. An oblique osteotomy is performed at the base of the distal phalanx of the ulnar thumb duplicate (the less hypoplastic) and the radial wedge is excised. The same osteotomy is applied to the distal phalanx of the radial thumb duplicate, but the radial wedge is preserved. The proximal phalanx and the bases of the distal phalanx are joined by bone suture. Axis correction and ligament stability are thus achieved without nail surgery. RESULTS: The patients were examined with a mean 24 months of follow-up (range: 12-36 months). The result was good in all four cases according to the Horii score. DISCUSSION AND CONCLUSION: This procedure combines an excision of the central part of the proximal phalanx and partial excision of the base of the distal phalanx. It provides axis correction and stabilization of the interphalangeal joint while avoiding subsequent nail dystrophy because a single nail is preserved. Preliminary results are encouraging: no axis deformity, instability or nail dystrophy has been noted. Nonetheless, the long-term results need to be evaluated. LEVEL OF EVIDENCE: IV retrospective study.

[Arthroscopic anterior capsular release in medial contracture of the shoulder secondary to brachial plexus birth palsy. Preliminary results]. / Arthrolyse antérieure de l'épaule sous arthroscopie dans les séquelles de paralysie obstétricale du plexus brachial. Résultats préliminaires.

PURPOSE OF THE STUDY: Retraction of the shoulder in internal rotation is observed in 25% of children with brachial plexus birth palsy (C5, C6 +/- C7). Early bone and joint deformities affecting the glenohumeral joint are the consequences. The stiff internal rotation requires surgical release which can involve the capsule and ligaments, muscles, or both. Internal release can be combined with muscle transfer to improve active external rotation. We report the results obtained with arthroscopic anterior capsular release combined with latissimus dorsi transfer. MATERIAL AND METHODS: From 1999 through 2006, fourteen children with a stiff shoulder in internal rotation secondary to brachial plexus birth palsy were managed in our unit. All had recovered biceps function six months after surgery. The glenohumeral dysplasia was analyzed on the preoperative magnetic resonance imaging. Pre- and postoperative passive external rotation (RE) were measured with the arm along the body and at 90 degrees elbow flexion. Internal rotation was measured using the Mallet score (hand-back test). Combined active abduction antepulsion was measured when the child was playing. Mean age at surgery was three years six months. Arthroscopic internal release was performed for eight children. All had an associated latissimus dorsi transfer. RESULTS: Among the 14 children managed in the unit, arthrolysis was not be performed in six, either because of the lack of an adequate electrode (two patients) or because the child presented posterior glenohumeral dislocation making it impossible to introduce the optic channel (four patients). Arthroscopic anterior release was performed for the eight other patients. These eight patients were reviewed at a mean three-year follow-up. Passive external rotation was improved, with a mean gain of 60 degrees with no recovery of passive internal rotation. The abduction antepulsion movement was also improved, mean gain 90 degrees . DISCUSSION: A stiff shoulder in internal rotation can develop during the first two years of life. Several techniques have been proposed for internal release. The origin of the progressive limitation of passive external rotation remains a subject of debate. Is it due to retraction of the internal rotators, or to capsule-ligament retraction, or both? In 1992, Harryman et al. demonstrated the role of the capsule and the coracohumeral ligament in limiting external rotation. Consequently, we have opted for early release (less than two years of age) using an arthroscopic method limited to the capsule and ligaments. Our results for passive external rotation are comparable to those reported by others. However, this technique enables preserved mobility for internal rotation. CONCLUSION: Arthroscopic anterior release limited to the capsule and the ligaments is an effective, minimally invasive technique. Leaving the internal rotator muscles intact preserves internal rotation of the shoulder and reduces the risk of anterior instability.

Gallium-pyridoxal isonicotinoyl hydrazone (Ga-PIH), a novel cytotoxic gallium complex. A comparative study with gallium nitrate.

The anti-proliferative activity of gallium-pyridoxal isonicotinoyl hydrazone (Ga-PIH), a novel gallium complex was compared with that of gallium nitrate, a known anti-tumor agent. At 50 microM, Ga-PIH inhibited CCRF-CEM cell growth by 45% compared to < 10% inhibition with gallium nitrate or PIH. The IC50s for Ga-PIH, gallium nitrate and PIH were 60, 84 and 68 microM respectively. The addition of exogenous iron as transferrin-iron to the culture medium reversed the cytotoxicity of gallium nitrate and PIH in a dose-dependent manner but had only minor effects on the cytotoxicity of Ga-PIH. The effect of these compounds on cellular iron uptake was measured since prior studies have shown that gallium perturbs iron transport into cells. Fifty micromolar Ga-PIH, gallium nitrate or PIH inhibited the cellular uptake of 59Fe-transferrin over 24 h by 65%, 32%, and 78% respectively. Although all three compounds inhibited iron uptake, only Ga-PIH produced a significant upregulation of cellular transferrin receptors. Since the cytotoxicity of Ga-PIH appears to be less influenced by extracellular iron and cellular transferrin receptor expression, it may have potential as an antineoplastic agent and should be further evaluated in animal tumor models.