Observation of the effect of gravity on the motion of antimatter.

Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.

Bleeding reduction after topical application of tranexamic acid together with Betadine solution in total knee arthroplasty. A randomised controlled study.

INTRODUCTION: Topical application of tranexamic acid to the knee joint before closure in total knee arthroplasty reduces postoperative bleeding without increase in complication. However, it is unknown the effectiveness of topic TXA performed with other topical medications, like povidone-iodine solution. MATERIALS AND METHODS: One hundred and twenty-five patients were randomized to receive 100mL of povidone-iodine solution (control: group A) or 1.5 (group B) and 3.0 g (group C) of topical TXA in povidone-iodine solution applied into the knee before closure in total knee arthroplasty. RESULTS: The patients in the TXA groups had higher mean postoperative hemoglobin levels (P=0.01 and P=0.03 in groups B and C, respectively) and a reduced postoperative blood loss in the TXA groups (P=0.07 and P=0.09 in groups B and C, respectively). No significant complications were observed. DISCUSSION: In this study, topical application of tranexamic acid after total knee arthroplasty together with povidone-iodine solution results in higher postoperative hemoglobin levels and lower blood loss compared with those in the control group without other complications. LEVEL OF EVIDENCE: I - I: high-powered prospective randomized trial.

Retinoic acid receptor-α signalling antagonizes both intracellular and extracellular amyloid-ß production and prevents neuronal cell death caused by amyloid-ß.

Alzheimer's disease (AD) is characterized by amyloid-ß (Aß) deposition in the brain, neuronal cell loss and cognitive decline. We show here that retinoic acid receptor (RAR)α signalling in vitro can prevent both intracellular and extracellular Aß accumulation. RARα signalling increases the expression of a disintegrin and metalloprotease 10, an α-secretase that processes the amyloid precursor protein into the non-amyloidic pathway, thus reducing Aß production. We also show that RARα agonists are neuroprotective, as they prevent Aß-induced neuronal cell death in cortical cultures. If RARα agonists are given to the Tg2576 mouse, the normal Aß production in their brains is suppressed. In contrast, neither RARß nor γ-agonists affect Aß production or Aß-mediated neuronal cell death. Therefore, RARα agonists have therapeutic potential for the treatment of AD.

Monostotic fibrous dysplasia of the clivus: image-guided endoscopic endonasal transsphenoidal surgery.

INTRODUCTION: Fibrous dysplasia is a non-heritable, congenital disease involving the bones. Its diagnosis relies on image examination and pathology. Treatment is usually conservative, but in cases of cranial nerve impingement or extension to the condyles, surgery should be considered. In this paper, we describe a singular case of monostotic fibrous dysplasia of the clivus in a child. CASE REPORT: A 14-year-old boy presented with chronic headache and diplopia. A neurological examination revealed palsy of the right VIth cranial nerve. The radiological findings were consistent with fibrous dysplasia, with a hypointense and isointense clival lesion on T (1)- and T (2)-weighted images, respectively. Surgical treatment was indicated by cranial nerve impairment. An endoscopic endonasal approach with an image-guided system was used. The patient was discharged four days after surgery and his diplopia improved postoperatively. DISCUSSION: A variety of surgical approaches have been used in the treatment of midline extra-axial cranial base tumors. Fibrous dysplasia of the clivus without expansion to the condylus can be removed with a transsphenoidal endonasal endoscopic approach. Preoperative imaging reveals the individual patient's anatomy and improves the intraoperative orientation. CONCLUSION: Image-guided transsphenoidal endoscopic surgery is recommended for its safety and minimal invasiveness.

Agnathia and associated malformations in a male rhesus monkey.

BACKGROUND: Agnathia is a rare malformation characterized by the absence of the mandible. METHODS: A male rhesus monkey with malformations was found dead and studied by internal examination, radiographs and histopathology. RESULTS: A case of a rare first branchial arch anomaly with agenesis of the mandible and tongue is presented. The animal also had visceral deformities. However, ears were normal in shape and only slightly low in position. The craniofacial malformations may reflect incomplete separation of the first branchial arch into its maxillary and mandibular processes. CONCLUSIONS: The association between the craniofacial and other corporal anomalies is unclear.

Endovascular treatment of carotid-cavernous fistulas: review of 12 cases.

Carotid-cavernous fistulas (CCFs) are an uncommon pathology in current neurosurgical practice. Furthermore, they generally present a challenge to the neurosurgeon because of both their deep location and the major neurovascular structures that surround them. CCFs consist of a vascular anomaly in which blood flows from meningeal branches of the internal and external carotid arteries, or directly from the internal carotid artery, into the venous circulation around and in the cavernous sinus. Twelve patients with direct and indirect/dural CCFs who underwent examination and treatment between July 2003 and February 2006 are reported here. All patients of this retrospective evaluation were symptomatic at the time of diagnosis, which was confirmed by cerebral angiography. The patients were treated by endovascular approaches and the CCFs were occluded. From our evaluation, we concluded that the endovascular procedure is safe, effective and minimally invasive in patients with CCF.

Work activities of practical nurses and risk factors for the development of musculoskeletal disorders.

Musculoskeletal and emotional disorders are important causes of reported diseases, causing medical absences, and eventually earlier decrease of work ability. This paper reports the results of a study carried out among practical nurses working at the Orthopedics and Trauma Institute. The objectives of the study were: (a) to describe the routine activities performed during day and night shifts, and (b) to compare the work activities performed in different wards during these shifts. A Brazilian version of the Work Ability Index--WAI (TUOMI et al., 1994) was answered by 83 practical nurses. Forty-three of them (52%) reported pains or musculoskeletal diseases, either based on their own opinion or diagnosed by a physician. These nurses were invited to join the second phase of the study and twenty-nine accepted it. All work activities performed in 29 shifts were observed and recorded. The results showed that day shifts were far more demanding in terms of the number of activities related to patients' care than afternoon and night shifts. Also, body postures associated with day work activities demanded important physical efforts. The number of nurses in charge during night shifts was substantially lower than during day shifts. This could lead to an overload and affect the health of the nurses.